When a lot of aspects of farming are out of our control, we need to focus on what we can manage by minimising any risks coming on to farm.
Certain management decisions bring in yield resilience rather than fragility and this can include a number of things. For example, we need to minimise nutrient loss and application costs whilst maximising application accuracy, all whilst having environmental costs in mind too. Having good quality inputs can address some of the risks so that we are managing risk out and not in.
Dry weather in spring means that crops need to be even more resilient to cope with the lack of moisture and have a root system that is large and deep enough to access water further down the soil profile. We need to maintain growth momentum once crops start growing again in the spring, which can be at quite low temperatures, 5°C for cereals and oilseed. Our first fertiliser application is vital as it gives the crop the best chance of accessing the nutrients applied as they are will have started growing before you’ve been able to get onto the land.
This can affect the fertiliser choice because not all nitrogen-containing fertilisers are plant-available straight away. Nitrates are the most available form for plants to take up immediately, without any conversions needing to occur, therefore ammonium nitrate (AN) products provide immediately available nitrogen to the crop. If we look at urea-based fertilisers they have to undergo a conversion in the soil before they become plant-available and therefore the crop has delayed access to the nitrogen.
Depending on soil conditions this can take 6-8 weeks and therefore we could really be slowing down the crop momentum; which we don’t want to do at that key timing in the spring. So, if you are concerned about this delay stopping crop momentum, apply a nitrate based fertiliser, such as YaraMila 52 S or ACTYVA S, as your first spring top dressing. Aim to apply the first 50-70 kg N/ha with either of these products that will also supply fresh, immediately available PK&S to these crops.
If you remove straw then you also remove the nutrients that are contained in it, which is fine of course but then they won’t be available to the following crop.
Removing both grain and straw with cereal crops removes 8.0-8.5kg/t of P2O5 and 10.5-12kg/t of K2O, therefore is it important to take this into account when calculating next season’s fertiliser plan.
Post-harvest soil sampling will, of course, give a good indication of the P&K levels. If the indices are below 1 then an autumn application of P&K is justified. However if the indices are 1 or above then autumn P&K applications are not necessary. At those kind of levels there will be sufficient P&K in the soil to establish cereal crops and an application of foliar phosphate, such as YaraVita MAIZEBOOST, could be applied with a herbicide spray if required.
The real demand for phosphate comes in the spring from March to May when a typical crop of winter wheat will require 1-2kg per day for optimum growth. Any phosphate applied in the autumn is unlikely to still be present in the soil in a plant available form and therefore won’t be able to supply this daily demand.
Therefore when purchasing P and K products make sure you think about the timing of application to meet the demand from the plant, otherwise you will be feeding the soil and most of the phosphate applied will have been rendered unavailable for the following spring.
For more information on different options for P & K and other nutrient solutions please visit yara.co.uk/agronomy-advice/
When buying fertiliser for spring application, many people fall into the potential ‘trap’ of getting straight nitrogen without thinking about the knock-on effects of this. Whilst nitrogen (N) is the most important nutrient, without sulphur (S), phosphorus (P) and potassium (K) the crop won’t be able to grow effectively.
We know that levels of both N and S in the soil are limited, and therefore the deficit in requirement needs to come from manures or mineral fertilisers. With P and K, we rely on soil indices to tell us how much to apply, but even on index 2 and above, fresh applications give a better use efficiency due to availability in the soil at the time crops require the nutrients.
This leads on to a compound NPKS being a good option for cereals, not only for the first application in February, but all the way through for an easy approach to fertiliser. “Aren’t NPKS a lot more expensive?” I hear you ask. You might be surprised to find out that they are actually more cost effective than urea/straight AN products are, and here’s why.
If we look at straight N then we have to think of applying P, K and S separately into the programme, this means we have 3 extra passes and 6 in total. If we think of the price of fuel at the moment, then this soon adds up to a significant amount - approximately £15/ha each pass.
If we think of the NPKS compound fertiliser then the additional benefits are 0.3t/ha from the spring P&K, 0.77t/ha from applying sulphur little and often and the increased accuracy of spreading is another 0.3t/ha. So, overall the benefit from applying an NPKS compound over straights is approximately 1.37t/ha, which at ~£240/t equates to nearly £330/ha for wheat crops.
Therefore, for a simple and cost-effective approach to nutrition for 2023, then a product such as YaraMila EXTRAGRASS (27-5-5+ 6% SO3) is a really good option.
If you are aiming for protein spec with your milling wheat this year, then the timing of nitrogen is the key. In order to hit the protein target that millers are looking for, then a separate application of nitrogen is required after the flag leaf final dressing.
The application needs to be separate in order to ensure the nitrogen goes towards building up the protein level within the developing grain. As well as timing, nitrogen source and rate are also important when trying to boost the protein, to ensure the nitrogen is utilised correctly in the plant.
Applying about 40kgN/ha (e.g. 120kg/ha of YaraBela Extran) at growth stage 51 (which is the start of ear emergence) can increase grain protein levels by up to 1%. This is possible to achieve without then compromising the yield. Yara trials showed that the separate application later in the season gave a boost in both yield and protein when applied at end of booting/start of ear emergence. For those on liquid systems, then an application of foliar urea (such as Chafer Nufol 20) applied later, at the milky-ripe stage, is the ideal timing for the same 40kgN/ha.
However, if the plant is deficient in certain micronutrients you’re less likely to have a positive impact on protein levels. Manganese and zinc, in particular, are important in the metabolism of nitrogen. If nitrogen metabolism is improved, then this increases the amount of nitrogen that is incorporated into the developing protein in the grain. Trials work, again, has shown that an application of zinc at T2 timing can increase grain protein by up to 1.4%! Therefore, it is important to ensure there’s no zinc deficiency if aiming for the milling premium - an application of YaraVita Mancozin or straight YaraVita Zintrac 700 will prevent this.
A crop of maize can produce up to 50 t/ha of fresh weight in just 4 months. For this amount of growth over a short timeframe to happen there needs to be a healthy, extensive root system for nutrient uptake from the start.
Phosphate (P) is a very important nutrient, key for growing the root system the crop requires to sustain the rapid growth, as well as being part of the transfer of energy within the plant. Weather plays a role in the availability of P, if soils are cold and wet when the maize is planted then P in the soil will have a very low level of availability, which is why placing some at drilling helps this by providing immediately available forms.
Nutrient availability in general decreases in dry soils, as we’ve had recently, and this will restrict root growth and therefore the ability to support the crop later in the season.
So how do we get around this? A foliar application of phosphate is the best way to overcome these early deficiencies and give the crop a boost in energy levels, both of these will help the crop develop a better root system to support later growth. YaraVita Maize Boost contains foliar phosphate, together with useful amounts of zinc, magnesium and potash. Applying it at the 4-6 leaf stage is effective for fast, efficient uptake through the leaf.
Biostimulants can also help during periods of abiotic stress, such as dry conditions. Trial work carried out in 2021 showed that YaraVita Biotrac, a biostimulant product, increased the yield in maize when applied in combination with YaraVita Maize Boost, by up to 4.4t/ha.
The majority of Irish arable soils are deficient in sulphur which means that most will need to factor this into their fertiliser strategy. It is easy to end up buying straight nitrogen products when new season pricing comes out, but most of the time an NS product is the most efficient way of feeding the crop.
For plants to utilise nitrogen correctly, sufficient sulphur levels are required due to the close relationship between the two nutrients. When applying sulphur it should go on little and often, the same way you would apply your nitrogen, because it has the same leachability characteristics in the soil. The addition of sulphur applied in this way typically increases the yield by an average of 0.50t/ha for wheat and oilseed.
However, the source of sulphur applied also makes a big difference. Elemental sulphur has to undergo an oxidation process before it becomes plant-available, this is weather-dependent and could take up to 6 weeks in the spring. Sulphur in the sulphate form is plant available and therefore the crop can utilise it quickly and efficiently.
The quality of the product is also a key factor for buying decisions and whether it spreads the required distance to give a good, even pattern. Fertiliser is a big investment and therefore buying a product that has a good CV, hard granules/prills (no dust), uniform in size and shape (no segregation), all nutrients in one granule/prill (even nutrition in the field) and has low emissions means an overall reliable return on investment.
YaraBela Axan (27% N + 3.6% S) is a high-quality NS compound which delivers these attributes and more. It is ideal for a multitude of crops when applied throughout the growing season, reducing the requirement of straight nitrogen, for a more efficiently grown crop.
When we were first looking at nitrogen applications, back in the winter, it was advisable to review the final N rate once we knew what crops and economics were looking like in the spring. Well, now it is that time!
With current fertiliser prices, the cost of applying nitrogen is still high, however wheat and oilseed prices are also high; which means the economic optimum has shifted back up to more normal levels. If we do the calculations then the economic optimum is now around 190-200kgN/ha, rather than the 160-180kgN/ha when crop prices were lower back at the start of the year.
This means that it is now worth pushing for yields and, on the whole, crops also look like they have good potential. The final dressing rate will of course depend on what you have already applied and also the crop type. If you are growing milling wheat then you will need to have the additional 40kgN/ha for increasing protein levels.
This can be added to the final application however trial work carried out has shown that, when it is applied as a separate dressing at growth stage 51 for solid or milky ripe for liquid, it can increase the protein levels by up to 1%.
YaraBela CAN 27%N is a quality granular fertiliser that spreads to over 40m and is ideal for the final application where straight nitrogen is required.
There are many types of biostimulants on the market, each with different purposes. What Yara products focus on is enhancing tolerance to abiotic stresses (e.g. extreme temperatures, drought, pesticide stress). They contain bioactive components such as fucoidan, mannitol, vitamins, organic acids, amino acids and also some of the nutrients that are involved in various mechanisms of the plant.
Ascophyllum nodosum, which is one of the compounds within Yara products, can induce hormone-like activity, improving the plant's hormonal perception and enhancing its effect. The composition of the product can also have an effect on many plant processes that could subsequently result in improved plant growth and yield improvement (e.g. increased photosynthetic efficiency, improved nutrient uptake, mitigation of abiotic stress effects through the mechanisms mentioned above, etc).
YaraVita Biotrac is a complex formulation containing nutrients and bioactive components from Ascophyllum nodosum, organic acids and vitamins. Biotrac can trigger various metabolic processes within the plant due to its composition; which impacts activities such as regulation of water, stress tolerance, stomatal conductance and detoxification of oxygen free-radicals.
This in turn can lead to improvements in the efficiency of plant processes and therefore result in improved plant growth and yield. Work shows that increases in both nutrient use efficiency, uptake and photosynthetic efficiency can be observed.
UK trials data has shown that when in combination with YaraVita micronutrient products, there were increases in yields observed. As an example, in a trial looking at different products on maize, when YaraVita Biotrac was used in combination with Maizeboost or Gramitrel, the yield was increased above those products applied alone - showing improvement in the crop’s efficiencies.
Micronutrients have a key role to play in the growth of all crops and have an impact upon crop efficiency and, ultimately, yield. Manganese, copper and zinc are important micronutrients for cereals and can increase the grain size and weight when in sufficient supply.
Of course, the main influencers on grain size are nitrogen and sulphur but, with potential reductions in these macronutrients due to the current situation, we must also focus on which micronutrients can help influence the grain. Don’t forget the number of grains - which we can influence with well-timed micronutrient applications.
Grain size in barley can be reduced by late nitrogen applications. Secondary tillers form ears with small grains, therefore affecting the overall quality of the harvest. Nitrogen applied early will ensure a canopy that is large, containing high levels of stem carbohydrate that is translocated to the developing grain during maturation. If we go back to micronutrients then both manganese and zinc have roles in nitrogen metabolism by the plant and therefore sufficient supply will improve grain weight.
Research has also demonstrated that manganese, copper and zinc have all increased the Thousand Grain Weight (TGW) in barley. When applying these nutrients at the T1 fungicide timing, we see increases in the thousand-grain weight and the number of grains per ear can be positively influenced with copper and zinc in particular. These three micronutrients have also been shown in the literature to improve disease resistance in crops, a healthier plant has improved defence mechanisms against fungal infection and therefore is better able to deal with them.
YaraVita Mancozin contains all three key nutrients and is therefore an ideal product to apply with the T1 fungicide timing on barley
Of course the first applications of nitrogen (and sulphur) are a high priority on farm, however, have you thought about micronutrient applications too?
Once crops begin the stem extension phase of growth they require a lot of nutrients to keep up with their rapid rate of development. This means the requirement for major nutrients increases but also the need for micronutrients increases as well. Don’t be fooled by terminology. ‘Micro’ doesn’t mean that these nutrients are less important but that the plant requires them in smaller quantities. A deficiency of any nutrient can cause major problems within the plant. Think of the Law of the Minimum, where any limiting factor will affect the overall yield of the crop – micronutrients can be those limiting factors.
Of particular importance is magnesium. Part of chlorophyll it is therefore vital to efficient photosynthesis and is required by the T1 timing to ensure there is sufficient supply. Think of all the chlorophyll production during the rapid phase of growth once the crops take off – not having enough Mg will mean less light is captured, therefore affecting crop development and eventually yield.
Tissue testing is the only way to see what is in the plant at that moment in time and therefore which micronutrients you will need to apply to keep the crop at optimal levels. However, if tissue analysis isn’t for you then an easy and effective alternative for cereals is to apply a multi-nutrient product such as YaraVita Gramitrel . This foliar product contains all the nutrients required by cereal crops in one can, and can be used to ‘cover all bases’. Long-term independent trial data shows that, on average, there is about a 0.5t/ha yield increase from YaraVita Gramitrel applied in the spring.
Oilseed had favourable establishment conditions and on the whole fields were looking good going into the winter period. Now that regrowth is starting we need to keep that momentum going with spring starter fertiliser and key micronutrient applications.
One thing that could slow that momentum is the availability of phosphate (P) from the soil. When soils are below 8C phosphate availability is less than 10%, this means that when the crop starts to regrow it can’t access the soil-P straight away. P is important for shoot growth and root growth, which can also be compromised after winter if the roots have sat in waterlogged, anaerobic conditions. These factors can slow the development of the crop early-on, until soil temperatures increase.
An application of a compound fertiliser, containing N, P, K and S supplies that fresh P for the crop to take up immediately, whilst soil-P is unavailable. Potash (K) is also key for root systems, particularly those smaller secondary roots, increasing their number and density. Therefore a product such as YaraMila Actyva S (16-15-15 + 6.5% SO¬3) supplies fresh P and K, along with the nitrogen and sulphur, all of which are critical to early regrowth in the spring.
Other key nutrients for oilseed rape in the spring are magnesium, calcium, boron, manganese and molybdenum. All of these are in the crop-specific, foliar micronutrient product YaraVita Brassitrel Pro. Long-term independent trial data shows that an application of 3.0L/ha of YaraVita Brassitrel Pro at the onset of stem extension gives a 0.29t/ha yield increase to oilseed rape, which currently gives a return on investment of more than 8:1. Having all the key micronutrients in one product also makes the application simple and efficient.
These two products cover all the nutrients required to kickstart the growth of oilseed this spring and set the crop up for building yield.
As crops got off to a good start in autumn, with favourable establishment conditions, many were quite advanced heading into winter. But after winter there is a risk that crop root systems have taken a knock by sitting in potentially cold, wet soils towards the end of last year. The last thing we want is to have good above-ground growth without the same below-ground to sustain it, therefore we need to keep the pre-winter momentum going once crops start to actively grow again.
In order to regrow that root system, fresh phosphate (P) and potassium (K) are vital nutrients to go with nitrogen (N) and sulphur (S) at the first nitrogen application timing. Soil-P, in particular, doesn’t become available until soil temperatures are 8oC and above, whereas the crop starts growing at 4-5oC. This means there could be a shortfall in available P. Along with a poor root system, this would be another reason growth could be stalled.
Applying an NPKS product, such as YaraMila Actyva S, at the first nitrogen timing will give the crop the vital nutrients it requires by a) providing immediately available nutrients so that the crop can take them up quickly and efficiently and b) replenish that root system to sustain the top-growth.
The second and/or third dressing(s) should then be an NS product such as YaraBela Axan, as we know that sulphur should be included with nitrogen applications. Split the sulphur into more than one application to get maximum nitrogen uptake and utilisation from sulphur sufficiency.
January is almost over already and spring is fast approaching; now is a good time to look at your soil results to help plan.
UK soils have changed a lot in the last few decades; whether it’s the 97% sulphur deficiency found in soils sampled or low average organic matter levels across arable land. The importance of taking a soil sample is well-documented, but should you be investing in more than just basic soil analysis?
Identifying Limiting Factors
The basic analysis will give you P, K, Mg and pH; which is a good start but what about micronutrients, organic matter and soil microbial activity? All are important to plant nutrition and you may be unaware that your soils are low in one or more of these elements, a broad spectrum analysis + soil health will give you this information to enable you to manage them.
With more and more emphasis on sustainability, we should start with a farmer’s number 1 asset – soil! In order to be able to monitor your soil and pick up on factors indicative of its health, you have to monitor it in the first place. Organic matter (OM) is a key indicator of soil fertility through the retention of nutrients and the ability to feed beneficial microorganisms in the soil. OM can take a while to build but you need to know your starting point so that you can monitor your progress in building the levels within your soils.
Another important aspect of soil health is the microorganisms within that are key to having a fertile, productive asset to work with. By carrying out a Solvita test you can monitor the level of respiration within the soil; which is an indicator of the amount of microorganisms present.
Once you have baseline levels for OM and microorganisms then you can try different practices to see how they can help increase the levels of each and work towards a more sustainable soil. This will mean better nutrient use efficiency, as well as other key benefits to your crop’s productivity.
The early spring growth period in cereal crops is an essential phase during which the foundation for high biomass is established. Biomass is a fundamental prerequisite to achieving high grain yields, this biomass is the result of achieving a good population of main shoots and tillers.
The tillering phase commences after leaf 3 is fully expanded and generally finishes when the ‘double-ridge’ stage of development is reached (i.e. just before GS 30.) This growth stage is typically reached by mid-March. The final number of tillers can therefore be manipulated through the appropriate use of inputs. One such input is crop nutrition. Nutrient deficiencies, especially nitrogen and phosphate, will limit early spring growth and development, thus reducing the number of tillers produced – this is then exacerbated even more in waterlogged conditions, such as we have experienced this winter.
The root structure of waterlogged crops will be poor - small and potentially damaged roots means a lower ability to scavenge the limited nutrients from the soil. Phosphate in particular, which is unavailable at low soil temperatures (below 8°C), is important for root growth. With the soils having little to no available P in early spring, fresh applications become even more important. Solid P applications are somewhat inefficient therefore foliar P should be considered as an early option.
A foliar application of phosphate gives an ‘energy boost’ to the crop, stimulating the growth of roots and consequently shoots. Not only does this give an immediate benefit by way of recovery and repair, it builds resilience, enabling the crop to overcome further potential stress points. YaraVita Magphos K is an ideal foliar product for this timing, kick-starting the cereal growth at this early phase.
If you do choose to apply foliar P then do so as soon as you can travel but ensure that you are ready to come back quickly with an application of, ideally, NPKS to ensure the crop doesn’t lose momentum as we don’t want to spark growth off only to let the crop run out of steam once it gets going.
With potentially reduced nitrogen rates this season, what else can you do to increase the nutrient use efficiency of a) the nitrogen you can apply and b) all the other nutrients that a crop requires?
The use of a nutrient management plan (NMP) is not only a good way to calculate how much fertiliser you need but also should be part of the overall farm strategy. Historically NMPs have been quite simple, giving you an overall fertiliser rate for each field - taking into account N, P and K.
As part of Yara’s Atfarm platform, we will soon be launching a more dynamic nutrient planning software package which will be much more helpful in planning your full crop nutrition programme (CNP).
After adding fields into Atfarm, it will give the user an option to create a nutrition plan (limited to cereals and oilseed currently but more crops coming soon!). By adding the usual parameters required for creating an NMP, such as soil type, rainfall area, yield, straw incorporated/removed, organic manures etc you will see the nutrition plan for your crop.
Where the Yara version of an NMP differs is the demand splitting of the nutrients. Rather than only giving you the total amount of N, P and K, Yara uses years of trials data and knowledge to split the nutrients out into the optimum timings, including all nutrients required for crop growth. Functionality also includes the ability to upload soil analysis results, which will then change your recommendation accordingly, making the interpretation and implementation of your lab results much easier.
These features make for a much more dynamic nutrition plan that will help improve nutrient use efficiency. Therefore, in a year where nitrogen is going to be one of the limiting factors of crop growth, the use of Atfarm can help improve overall nutrient efficiency and so increase the efficiency of the nitrogen that you are able to apply.
Due to the European gas price moving from $6 to $42 (as I write this) we have seen the cost of production of fertiliser increase drastically due to natural gas being part of the manufacturing process – production costs have risen by €200/t this week alone!
Therefore the price you bought at will impact upon the economic optimum nitrogen (N) rate you should apply. If you bought earlier on in the year at €280 for example, your economic optimum wouldn’t have changed and you’ll be ok to stick with, say, 220kgN on winter wheat. However, if you have bought the majority of your nitrogen in the past few weeks (now above €500/t at the time of writing this) you may need to adjust your rate.
When looking at N dose trial data you see a response curve - as the rate of nitrogen increases, so does the yield – until you get to a certain point where the curve plateaus and then starts to decrease again at high rates of nitrogen. From this curve, you can see the biological optimum N rate. You can also calculate the economic optimum N rate; which takes into account the crop price as well as the fertiliser price.
From these trials we also know that the first 100kgN gives us the best response and therefore best return on investment (ROI) – no matter how much the fertiliser costs. The next 60kgN also gives us a good response and ROI. It is the next 50-60kgN/ha that relies on crop/fertiliser pricing, crop potential, weather etc to see if it is an economically viable application.
So what does all that mean?? If you had to buy at a high price you may need to reduce your fertiliser rate. Taking wheat as an example, we know that a lower rate of 160kgN/ha gives a good ROI, independent of fertiliser price. When we come to spring we can then re-evaluate whether the final 50-60kgN is required; based on crop pricing, potential, mineralisation and use of tools like the N-Tester to judge whether it is economically the right thing to do.
Establishment is so important when growing oilseed, getting the crop up and away to combat pest pressure is the aim of the game.
At the time of writing there has not been any significant rain for weeks in some areas; which is a worry for newly emerging oilseed crops as moisture is key to getting good establishment. With rain on the forecast, hopefully, just in time, we should see a flush of growth from the nutrients released from soils. If fertiliser wasn’t applied at drilling you’ve got until the end of October to apply up to 30kgN/ha if you’re in an NVZ, to give the crop the best chance of establishing successfully.
Once oilseed has reached the 4 true leaf stage (GS14) it is safe to apply some of the key micronutrients to ensure growth isn’t hindered at all going into the winter. Oilseed can put a lot of biomass on over a short space of time if conditions are right, which means there is the potential for crops to deplete micronutrients levels in the soil.
A simple way to apply all of the key micronutrients required, in the autumn, on oilseed is to use a multi-nutrient, crop-specific product such as YaraVita Brassitrel Pro. This mix contains magnesium, manganese, calcium, boron and molybdenum – vital micronutrients for this crop, particularly if we want to aid establishment.
Yara conducts independent trials each year and over the past 6 years the data has shown an average yield response of 0.3t/ha from an application of Brassitrel Pro both in the autumn and followed up in the spring. This means it is well worth applying as the return on investment is several times the cost of the product.
An added benefit from making sure the crop has all the nutrients it requires in the autumn is that a healthier plant is better able to cope with disease pressure and some of these nutrients have been shown to decrease the incidence of disease significantly. Think of it as a healthy animal not being as susceptible to illnesses as one that doesn’t have a sufficient nutritional diet, it is the same for plants.
Micronutrients are essential for growing a healthy, productive crop that is working efficiently throughout its lifecycle. There are different micronutrients that are key to each crop but on the whole, there are certain nutrients that are required at specific times to get the most out of your crops.
If we think about crop establishment, manganese and magnesium (which can also be thought of as a secondary nutrient) are the key micronutrients, on top of our major, or primary, nutrients nitrogen, phosphate and potassium. Magnesium is a key nutrient due to its central role as part of the chlorophyll molecule, without magnesium there wouldn’t be any chlorophyll and the plant wouldn’t be able to carry out photosynthesis.
Magnesium is also involved in enzymatic reactions in the plant, increasing their velocity as well as the formation of proteins and energy transfer. When a seed has germinated we want the growth to be unhindered and the plant’s processes to be working at full capacity to get the seedling growing away from pest damage for example. Magnesium has many roles within the plant and so having a deficiency during the early stages of growth will have a real impact on the overall capability of the crop establishing.
Whilst soils will have some level of magnesium present, it is often in an unavailable form to the plant and therefore deficiencies can easily occur, even during the early stages of growth. Mg deficiency symptoms are usually first seen in the older leaves with paler leaves initially and as it becomes more severe the leaves will have interveinal chlorosis (yellowing) and eventually the whole leaf will be yellow. This is due to magnesium being a central component of the chlorophyll; which gives plants their green colour.
Manganese is, again, important for enzymatic reactions in the plant, production of amino acids and chlorophyll as well as the metabolism of nitrogen. All of which are, of course, important for a newly-establishing plant. Symptoms of manganese deficiency are seen on the younger leaves as chlorotic spots and streaks which, over time, turn grey; with overall plant growth stunted. Deficiency is made worse by unconsolidated soils, which is why the areas around tramlines can appear darker green due to the more compacted soils.
You can see there are similarities between magnesium and manganese in which processes they are involved in, which is why these two nutrients are particularly important to plant growth, especially near the start of its life. If conditions are right, crops can put a lot of biomass on before winter and therefore autumn applications of magnesium and manganese can help ensure crop growth isn’t being held back at this critical phase.
Another reason to ensure the crop has good levels of micronutrients is the fact that a healthy crop is better able to defend itself against disease and pest pressure. Think of it as a healthy animal being less likely to succumb to disease than one that is lacking good nutrition from a balanced diet – it is the same for plants.
Work has been carried out to show how nutrients affect the incidence of disease in plants; large reductions in disease came from magnesium, manganese, copper, boron and zinc. These are the key nutrients to apply to autumn crops such as cereals and oilseed, the fact that applying them could also decrease the level of disease (and therefore fungicide spend) is an added bonus.
Lancrop laboratories see many routine tissue analysis results each year and if we look at the key nutrients for the 2021 season then there are still high numbers of deficiencies seen.
Level of deficiency in samples
To make life easier Yara has developed crop-specific products for cereals and oilseed in the form of YaraVita Gramitrel and YaraVita Brassitrel Pro which contain all the key micronutrients for the respective crops.
Gramitrel contains magnesium, manganese, copper and zinc, key for cereal crops, whereas Brassitrel Pro contains magnesium, manganese, calcium, Boron and molybdenum which, you’ve guessed it, are key for the oilseed crop. Having all the key nutrients in one can takes the hassle out of the autumn application and these products tank mix with most autumn pesticides too (you can check your mixture at tankmix.com). You can then follow them up with another application in the spring to catch the key growth timing or take a tissue test to go down the more precise route of applying straight micronutrients.
Whilst having a healthier plant might sound like a good thing can you equate this to yield increases? The answer to that is yes! Yara carries out trials on these products each year and there is a long-term average yield benefit over the past 6 years of 0.30t/ha from both cereal and oilseed crops. However each season is different – for example, this year’s trial gave a massive 1.0t/ha yield increase from 2 applications of Gramitrel (autumn and spring)! The return on investment (ROI) can be huge when you get these kinds of increases but there is also a good ROI on the long-term average of 0.3t/ha, making the applications worth it.
So, prevent your crops from lacking nutrition this autumn that will stop them from growing at their optimum and giving them the best chance of overwinter survival and, ultimately, yield next harvest.
People like to know where the things they buy originate from, so being able to trace products from production to end-use is becoming more and more of a requirement. Do you feel the same way about your fertiliser?
Being able to trace each product back to where it was produced is vital for a number of reasons. For one, if there happens to be an issue with a particular product then it is easy to trace it back through its journey to find out where the problem occurred. Having the ability to track a product in this manner gives you the reassurance that you can trust the product. A further reason for the increasing importance of traceability is the ability to calculate the carbon footprint of your crop, a topic companies and consumers alike, are becoming more interested in.
Each product from Yara has a label that contains information unique to that product. On a 600kg bag of YaraBela Axan, for example, can see from the front of the bag, at the bottom right, which factory the particular product has come from; which for example could read Sluiskil – our factory in the Netherlands. The back of the bag has lots of information about the product including the product grade code and, again, the factory where it was produced. This information is particularly useful when it comes to spreader settings as there will be particular settings for YaraBela Axan from Sluiskil (also can be abbreviated as SLU). Using the product code and the factory of origin you can look up, on your spreader manufacture’s website, which spreader settings are required for that particular product.
Another useful label is in the inner liner – this will tell you which bagging facility the product came from – i.e. AVO would mean the Avonmouth facility, along with a unique bag number.
You can rest assured that any products you buy from Yara can be traced back to where they were bagged or filled, to the factory they were produced at, and also the batch to which they belong.
Depending on pricing, it may be tempting to take a PK holiday when planning the coming season’s nutrient strategy.
When prices are higher then it probably isn’t the year to try and build indices as, economically, it might not be viable, but we still need to think about crop offtakes and a maintenance application for P&K. If we are only applying a minimum dressing to cereals this season then the most important detail is to make sure it is applied as a spring application.
Soil temperatures in the autumn soon start to drop, especially if you’re delaying drilling due to grass weed control. Phosphate availability and crop uptake are greatly reduced in cold, wet soils therefore if you’re applying it in October/November it is unlikely to be taken up by the plant (and won’t become available in early spring).
So if we, again, think about the economics of this spring application surely it is better to apply 0-24-24 or straights because they are the cheaper option? Actually, these two options are one of the more expensive ways to apply P, K and S due to the additional cost of the extra passes (labour, fuel etc), therefore you lose the saving you made on the product through these overheads.
Applying a compound NPKS, such as YaraMila 52S, at that first nitrogen timing gives you a spring PK yield benefit (on average 0.31t/ha), a sulphur yield benefit (on average 0.9t/ha when followed up with NS product) as well as enabling you to have a minimal number of passes. Whilst the amount of P&K might be lower, you should still be applying enough to cover the crop offtake and therefore aren’t depleting soil reserves. Another approach is YaraMila Extragrass applied all the way through the season – both of these options give you well over £100 margin over applying straight nitrogen or P&K in the autumn/as separate applications.
With harvest well underway everyone is busy, but spending a bit of time taking a grain sample for analysis could pay off for next season.
Grain analysis has been available in the UK for a long time, however, it is not often carried out on-farm as a routine like soil or tissue analysis. Results from analysis show nutrient levels in the grain and therefore can identify whether sufficient levels of each nutrient were present for the crop in that growing season.
Having this data can then show you whether your crop nutrition strategy worked; did the crop have everything it needed to grow to its optimum? This ‘look back’ at the season then allows you to change your fertiliser strategy for the next season i.e. if the grain results are coming back as low in manganese then you need to review the amount or timing of application next season.
Sulphur is a good example of how to utilise the results you get from the analysis of the grain. An N:S ratio of below 17:1 is the target for wheat; if the ratio exceeds this it is an indication that there wasn’t enough sulphur available to the crop when it required it.
It’s not just the major nutrients that are useful, micronutrients are also measured in grain analysis and are, again, a good way to see whether they were at sufficient levels throughout the season. Don’t forget Liebig’s law of the minimum in which any limiting factor has the potential to stifle optimum yield, this of course includes micronutrients.
Therefore, grain analysis is another way in which to fine-tune nutrition to ensure that the crop is getting what it needs when it needs it – ultimately getting towards that optimum yield.
The idea of a starter fertiliser for oilseed is to improve establishment and get the crop up and away as quickly as possible. It could be tempting to wait until the crop is up and established before applying fertiliser but this could lead to a self-fulfilling prophecy - if you haven’t set the crop up with the best chance from the off, you can’t expect it to establish well. So for application timing, fertiliser should be placed if possible or applied soon after drilling to give the crop the best chance to establish. Trials have shown that placing fertiliser can increase yields by around 0.2t/ha; which is significant with recent pricing for oilseed.
An NPK product is ideal as a starter fertiliser. We need phosphorus (P) for root and shoot development and potassium (K) also helps with root growth and water regulation; which could be very helpful if we hit a dry spell after drilling. By ensuring there is enough K for optimal stomatal opening and closing, the plant will be better placed to cope with drier conditions.
The rate of nitrogen applied can differ depending on whether you plan on placing or broadcasting the fertiliser, but you’re looking at 25-30kgN/ha at this timing. Any fertiliser should be applied before the 15th of September, to comply with nitrates regulations.
Trials work has also shown that using an NPKS in the autumn can help with overwinter survival rates too with 90-100% survival when compared to an NS grade at around 38% survival. Work has shown that potassium acts like an “anti-freeze” in the winter too by lowering the cell’s sap freezing point and preventing frost damage.
Therefore when thinking of all those points a perfect grade is YaraMila New 18's + S (18-6-11 + 2.5% S) to give your oilseed crop the best chance this autumn.
A crop of maize can produce up to 50 t/ha of fresh weight in just 4 months! For this amount of growth to happen, over such a short timeframe, there needs to be a healthy, extensive root system for nutrient uptake right from the start.
Phosphate (P) is a very important nutrient, key for growing the root system the crop requires to sustain the rapid growth, as well as being part of the transfer of energy within the plant. Weather plays a role in the availability of P. If soils are cold and wet when the maize is planted then P in the soil will have a very low level of availability, this is why placing some at drilling helps by providing it in immediately available forms. However cold conditions at drilling aren’t the only weather-related issue for maize. In dry soils, as we’ve had recently, nutrient availability in general decreases. This will restrict root growth and therefore the ability to support the crop later in the season.
So how do we get around this? A foliar application of phosphate is the best way to overcome these early deficiencies and give the crop a boost in energy levels. Both of these will help the crop develop a better root system to support later growth. YaraVita Maize Boost contains foliar phosphate together with useful amounts of zinc, magnesium and potash. Applying it at the 4-6 leaf stage is effective for fast, efficient uptake through the leaf.
Later on in the season, once the crop has reached 1-1.2m high, maize can be given a further boost by applying YaraVita Safe-N 300. This helps maximise efficient leaf canopy development.
If you are aiming for protein spec with your milling wheat then the timing of nitrogen is the key. Reaching the protein target that millers are looking for requires a separate application of nitrogen after the flag leaf final-dressing.
The application needs to be separate in order to ensure the nitrogen goes towards building up the protein level within the developing grain. As well as timing, nitrogen source and rate are also important when trying to boost the protein, to ensure the nitrogen is utilised correctly in the plant.
Applying about 40kgN/ha (e.g. 120kg/ha of YaraBela Extran) at growth stage 51 (which is the start of ear emergence) can increase grain protein levels by up to 1%. This is possible to achieve without then compromising the yield. Yara trials showed that the separate application later in the season gave a boost in both yield and protein when applied at end of booting/start of ear emergence. For those on liquid systems then an application of foliar urea (such as Chafer Nufol 20) applied later, at the milky-ripe stage, is the ideal timing for the same 40kgN/ha.
However, if the plant is deficient in certain micronutrients you’re less likely to have a positive impact on protein levels. Manganese and zinc, in particular, are important in the metabolism of nitrogen. If nitrogen metabolism is improved then this increases the amount of nitrogen that is incorporated into the developing protein in the grain. Trials work, again, has shown that an application of zinc at T2 timing can increase grain protein by up to 1.4%! Therefore it is important to ensure there’s no zinc deficiency if aiming for the milling premium - an application of YaraVita Mancozin or straight YaraVita Zintrac will prevent this.
When fertiliser applications are still going on you’re probably not thinking about next season’s requirements, however, don’t get caught out by the fertiliser industry pushing you to order quickly, without planning, once the new season pricing comes out.
We know that the majority of UK arable soils are deficient in sulphur so it is likely you will require a product containing sulphate, an immediately available form of sulphur for plants. Trial work has shown that sulphur should be applied little and often with nitrogen to get a yield increase of more than 0.5t/ha, therefore decreasing the amount of straight nitrogen required.
P and K requirements also need to be planned, the timing for P and K is crucial to meet the nutrient demand. Irrespective of your indices, 35kg/ha of fresh P and K should be applied in spring, just before the crop demand is at its highest; which is March to May. We know that 70% of P is taken up in this 6-8 week period, therefore it makes sense to apply it when it requires it, in a plant-available form. There is also a yield benefit to this fresh, spring-applied approach of 0.30t/ha on average.
Another consideration should be ammonia emissions. During dry conditions, there is a greater risk of volatilisation, and therefore ammonia is released into the atmosphere. The source of nitrogen you choose can make a big impact on the level of these emissions. For example, the emission factor for urea is 13.8% whereas ammonium nitrate (AN) has one of the lowest ammonia emissions at 2.7%. So, by using AN rather than urea you are reducing ammonia emissions by 5 times. If you are thinking of reducing emissions by using urea + inhibitor in the future, emissions from this combination are still 2.5 times greater than AN – making it the best option for cleaner air.
So with all those things taken into account a good fit for that first spring timing on most crops is YaraMila Actyva S (16-15-15 + 6.5% SO3) with subsequent applications an NS compound such as YaraBela Axan (27%N and 9%SO3).
When it comes to the T2 flag leaf application there are a few points that we need to consider to ensure the crop is well equipped for the next stages of development.
The best way to know what micronutrients are in the crop is to carry out tissue analysis. This will give you an idea of what could be edging towards deficiency and therefore gives you time to order the right micronutrients to go into the T2 spray. What we don’t want to do is only use tissue testing when we see a deficiency symptom, as this means that potential yield is already being affected.
Luckily there is some rain in the forecast which means crops will finally be able to access the nutrients in the soil therefore make sure you allow 3-5 days or so after the first rains to enable this to happen, otherwise you might get skewed results.
A key micronutrient at this timing is magnesium (Mg). We want to keep the canopy green so that it can intercept light and eventually turn this into yield, magnesium can help with this. Mg is the central component of the chlorophyll, the more chlorophyll the more light interception. If there is a shortage of Mg then this process won’t be working at full efficiency and therefore yield won’t reach its full potential. We want to remove any limiting factors to the crop therefore ensuring it has the full ability to capture the light is critical.
Foliar phosphate and potassium can also help at the T2 timing. Phosphate is a key part of energy transfer within the plant and therefore is important for the process of redistributing stem carbohydrate as the crop moves towards grain production. Potassium also has a key role in this process therefore a useful foliar product at this timing is YaraVita Magphos K. This product, as the name suggests, contains all three of the nutrients mentioned and is a great fit for the requirements of the crop at this crucial timing, applied at 5 litres/ha.
Maize has a high demand for nutrients due to its high yield potential. These high yields of 40+ tonnes/ha can only be achieved if the crop can access enough nutrients via its roots, and as the plant grows, through foliar applications.
Zinc and magnesium deficiencies are the two most widespread nutritional disorders in maize. Zinc is important for photosynthetic activity. Magnesium is essential for the early establishment of the plant. A deficiency is reflected in reduced crop yield at harvest.
Phosphorus and potash are primary nutrients, however, many soils have not got the capacity to deliver an adequate supply. Where phosphate availability is reduced because of soil pH or where its uptake is impaired due to dry soil conditions, foliar phosphate will help. It is translocated from the leaf to the roots very effectively, maintaining root development.
One or more of the above is often deficient in the growing maize plant. This nutritional shortage is particularly important as the plant reaches the 4 to 5 leaf stage as it is now that yield is being set. Maize stressed at this point can result in tall, thin plants, with poor root systems and reduced leaf area. Reduced leaf area captures less light, resulting in lower yields.
To overcome the risk of nutrient deficiency, apply foliar nutrients at the 4 to 5 leaf stage. YaraVita Maize Boost is specifically formulated for foliar applications on maize. It will deliver a high concentration of phosphate, zinc, magnesium and potash to maximise maize yield and quality this harvest.
As oilseed crops are now flowering we need to think about maintaining the green area duration (GAD) to ensure we can get the best yields. Keeping the crop greener for longer means that it is able to intercept more light (energy) which, via photosynthesis, it can use to ‘fuel’ pod fill and therefore create yield. Light is intercepted by the green parts of plants, this includes the green pods too once flowering has finished. So by maintaining the green parts of the plant you are effectively extending the period where the crop can turn energy into yield.
Foliar nitrogen is an effective method of maintaining the GAD and there are a few options to choose from to suit each grower’s individual needs. Foliar urea is a popular option that typically gives an extra 0.25t/ha yield (worth over €97/ha) from 200l/ha application at the end of flowering.
Some other options for foliar nitrogen are YaraVita Safe-N 300 which, again, is applied at the end of flowering or YaraVita CropLift Pro (applied at the same timing). YaraVita CropLift Pro also contains a vast range of other nutrients, both macro and micro, to give the crop a boost. This could be particularly beneficial this season due to abiotic stresses on the crop such as low levels of rainfall.
Trials conducted in 2020 showed average yield increases of 0.35t/ha from an application Safe-N and 0.33t/ha from the application of CropLift Pro, both at the end of flowering.
The amount of nitrogen we apply to a crop is influenced by a number of factors, but two particular principles are the main focus.
Firstly is the biological requirement - the amount required to satisfy the crop’s demand, after the soil supply has been factored in. This is where the use of analytical tools, whether destructive analysis via a laboratory or by data collection from crop sensors/images, comes into its own. The second is the economics at the time of application, which is a function of the crop and nitrogen fertiliser value.
If we consider the current economics, comparing present-day with 12 months ago, shows that whilst both grain and nitrogen fertiliser have increased, grain prices have risen by a higher percentage. We can use this information to calculate the ‘Breakeven Ratio’, i.e. how much grain is required to cover the nitrogen value. This calculation reveals that the grain:nitrogen ratio has moved down from 5:1 to 4:1 in the wheat crop. Using the well-established AHDB RB209 Guidelines, then this affects the optimum rate of nitrogen by adding an extra 10 kg N/ha into your planned recommendation.
Of course, the value of your nitrogen will have been affected by your purchasing policy. Those that purchased the bulk of their requirements early will actually be operating at an even lower breakeven ratio, i.e. 3:1. If you are in this position then you should be considering adding 20-30 kg N/ha onto your recommendation. This extra should be applied to your middle dressing where it will have the greatest impact on yield and profitability, then you should start to focus back on the biological aspects i.e. ensuring sufficiency of supply with the final application. This final application can be fine-tuned using Yara’s tools and services e.g. Atfarm and N-Sensor.
The fertiliser spreaders have been busy applying macronutrients but have you thought about micronutrients at this time too?
Once crops start to extend they require a lot of nutrients to keep up with their rapid rate of growth. This means the requirement for major nutrients increases but also the micronutrients. The term ‘micro’ doesn’t mean that these are less important but means that the plant requires them in smaller quantities; a deficiency can still cause serious growth issues within the plant.
Magnesium, which is part of the chlorophyll and therefore vital to efficient photosynthesis, is required by both cereals and oilseed in the spring. Think of all the chlorophyll production during the rapid phase of growth once the crops take off – not having enough Mg will mean less light capture and therefore will affect crop development and, in turn, yield. As well as Mg, manganese, copper and zinc are key for cereal crops and manganese, calcium, boron and molybdenum are vital for oilseed.
Tissue testing is the only way to see what is in the plant at that moment in time and therefore will show you which micronutrients you need to apply to keep the crop at optimal levels. If you don’t want to carry out a tissue test then you could apply a multi-nutrient product such as YaraVita Gramitrel (Mg, Mn, Cu, Zn) on cereals and YaraVita Brassitrel Pro (Mg, Mn, Ca, B, Mo) on oilseed. These products have the specific, key nutrients required for those crops and can be used to ‘cover all bases’ if tissue analysis isn’t possible.
Trials carried out in 2020 by Yara showed that applying these micronutrient mixtures gave 0.78t/ha yield benefit in wheat from 2.0l/ha at T1, with the long term average giving 0.41t/ha (2016-2020). For oilseed at stem extension, we got a 0.59t/ha yield increase from 3.0l/ha with a long term average giving 0.30t/ha (2015-2020).
I have spoken previously about keeping the crop momentum going and, along with your first nitrogen dressing, foliar applications of nutrients can also play a part in this.
YaraVita MagPhos K can be a useful tool at this early timing. As the name suggests it contains magnesium, phosphate and potassium and is a great way to keep the momentum going. Applied at the T0 timing, a week or so after you’ve applied your first fertiliser application, it will give the crop a boost between the nitrogen applications.
It does this by being taken up more efficiently through the leaf for effective utilisation, therefore enabling the crop to immediately access the Mg, P and K. Another benefit of this application is the effect on the roots, both P and K are key for building the root system. This is then beneficial for improving the uptake of the nutrients applied at the first nitrogen dressing as well as subsequent applications.
This two-pronged approach makes sure that the crop always has access to these key nutrients as it moves towards that rapid phase of growth and that its growth doesn’t stall in between nitrogen applications.
The next key timing for a foliar application would be with the T1 fungicide timing. To keep things simple you can use the crop-specific micronutrient mix for cereals, YaraVita Gramitrel, which contains Mg, Mn, Cu and Zn. This covers the key micronutrients for cereals and therefore is a useful tool if you don’t want to do tissue testing.
However, if you think that you’ll have particular deficiencies then it is a good idea to take some tissue tests a couple of weeks prior to your T1 application so that you can order the specific micronutrients.
As crops got off to a good start in autumn, with favourable establishment conditions, many were quite advanced heading into winter. However, with above-average rainfall levels in December and January, there is a risk that their root systems have taken a knock due to sitting in wet, anaerobic conditions. The last thing we want is to have good above-ground growth without the same below-ground to sustain it, therefore we need to keep the pre-winter momentum going once crops start to actively grow again in a few weeks’ time.
In order to regrow that root system fresh phosphate (P) and potassium (K) are vital nutrients to go with nitrogen (N) and sulphur (S) at the first nitrogen application timing. Soil-P, in particular, doesn’t become available until soil temperatures are 8oC and above, whereas the crop starts growing at 4-5oC – meaning there could be a shortfall in the available-P. This would be another reason growth could be stalled, along with the poor root system.
Applying an NPKS product, such as YaraMila ActyvaS, at the first nitrogen timing will give the crop the vital nutrients it requires by a) providing immediately available nutrients so that the crop can take them up quickly and efficiently and b) grow that root system back to sustain the top-growth.
The second and/or third dressing(s) can then be an NS product such as YaraBela Axan, as we know that sulphur should be included with nitrogen applications to split the sulphur into more than one application and also get maximum nitrogen uptake and utilisation from sulphur sufficiency.
January is almost over already and spring is fast approaching; now is a good time to do some soil sampling if it wasn’t done in the autumn.
UK soils have changed a lot in the last few decades; whether it’s the 97% sulphur deficiency found in soils sampled or low organic matter levels across arable land. The importance of taking a soil sample is well-documented, but should you be investing in more than just basic soil analysis?
The basic analysis will give you P, K, Mg and pH; which is a good start but what about micronutrients, organic matter and soil microbial activity? All are important to plant nutrition and you may be unaware that your soils are low in one or more of these elements, a broad spectrum analysis + soil health will give you this information to enable you to manage them.
With more and more emphasis on sustainability, we should start with a farmer’s number 1 asset – soil! In order to be able to monitor your soil and pick up on factors indicative of its health, you have to monitor it in the first place. Organic matter (OM) is a key indicator of soil fertility through the retention of nutrients and the ability to feed beneficial microorganisms in the soil. OM takes a long time to build but you need to know your starting point so that you can monitor your progress in building the levels within your soils.
Another aspect of soil health is the microorganisms within the soil that are key to having a fertile, productive asset to work with. By carrying out a Solvita test you can monitor the level of respiration within the soil; which is an indicator of the number of microorganisms present.
Once you have base-line levels for OM and microorganisms then you can try different practices to see how they can help increase the levels of each and work towards becoming a more sustainable soil. This will mean better nitrogen use efficiency as well as other key benefits to your crop’s productivity.
In contrast to last season, there are many well-established crops out there that went into great conditions and put on good biomass going into the winter. On the whole, we have had a mild winter so far, if this continues through January and into February it could mean even more growth before the land is dry enough to spread fertiliser.
If your crops are forward this needs to be taken into consideration when planning your first nitrogen application, weather permitting, at the end of February. With a mild winter comes mineralisation, therefore nitrogen is available to the crop and many forward crops are showing how much nitrogen they have been able to take up so far by their amount of growth.
We want to keep the crop momentum going because we don’t want the crops to run out of steam before the period of rapid growth come March/April. However with forward crops then we don’t need to go on with as high a rate as we might with a late-drilled, backwards crop (up to 100kgN/ha). 60-70kgN/ha should be enough as a first dressing to maintain the momentum of a forwards crop, applied mid to end of February or as soon as possible after this is soils are still wet.
Ideally, an NPKS compound product, such as YaraMila New 18's + S should be applied as this gives the crop fresh phosphate when the soil-P might not be available yet, as well as sulphur to aid nitrogen uptake and utilisation. A second option is YaraMila Extragrass, another NPKS product, which can be used all the way through for cereals and oilseed for a straight forward macronutrient strategy.
Historically, the interpretation of tissue analysis has been based on guidelines relating to early season crop growth stages and in many cases, these guidelines have been established from potentially dated research sources.
Yara Analytical Services has gathered an unprecedented dataset of tissue analysis with millions of results built up over the years. This enables them to utilise this data to look at nutrient trends and benchmark nutrient levels against crop productivity. They were able to track how nutrient levels in various crops changed throughout the season and show, with confidence, evidence to change the current static guideline levels to growth stage-specific guidelines for improved interpretation and in-season crop nutrition decisions.
If we take nitrogen, for example, the historical guideline is at 3%, whereas the samples in the dataset showed that the levels tracked 4% - which is in line with where growers would typically want N levels of a crop to be. Looking at phosphate then the guideline is 0.3% throughout the season, but we know the crop has a higher demand for phosphate in the spring and that demand reduces as the crop reaches maturity. The dataset of leaf analysis results reflected this change in demand, thereby giving cause to change to a dynamic guideline for leaf phosphorus that follows the same pattern throughout the crop cycle.
The project showed that all nutrients measured in a leaf tissue analysis follow their own pattern of rising, maintaining, or declining tissue levels based on the requirement at key crop growth stages. These patterns have been used to establish Yara’s new set of leaf tissue analysis guidelines. We can look towards a dynamic guideline that changes as the crop grows, ensuring a more accurate representation of each nutrient within the crop at specific timings.
Yara announced its plan to produce Green Ammonia earlier in the year but what does this actually mean?
In order to produce ammonium nitrate (AN) fertilisers, ammonia is mixed with nitric acid to produce a liquid ammonium nitrate solution, this then goes on to produce the prills or granules that you’d recognise as fertiliser. The ammonia that is used for this process is produced with hydrogen gas from fossil fuels, mainly natural gas (methane), and therefore is classed as ‘brown’ ammonia due to its use of natural resources.
Green Ammonia is produced in a different way. H2O undergoes electrolysis, which is powered by renewable energy sources such as wind and solar power, in order to get the required hydrogen gas. Nitrogen is obtained from the atmosphere (which is 78% nitrogen gas) and two undergo the Haber-Bosch process. The end result is Green Ammonia, made from renewable sources. Unlike in the traditional ‘brown’ ammonia method, there is zero CO2 ‘waste’, therefore there is only a very low carbon footprint associated with Green Ammonia.
This is increasingly important as consumers want to know the carbon footprint of their purchases and it is thought that all food items will show a carbon footprint value in the near future. Every process needs to be sustainable and have as little impact on climate change as possible. With ammonia being the second-most-widely produced commodity chemical globally, (annual production volume of over 180 million tonnes) this new method would make a massive impact worldwide.
Sulphur is an important nutrient for all crops, it is the precursor to proteins which are of course the building blocks of yield.
Due to the lack of sulphur from atmospheric deposition (0-5kg S/ha/year) there is a shortfall which can be filled with organic manures and of course mineral fertiliser. Organic manures have an inconsistent amount of sulphur and therefore tend to cause more variability across a field. Also, they can be applied in the autumn when the crop isn’t able to utilise the sulphur fraction.
Even though the importance of sulphur is well known, there are still growers who don’t apply any. The relationship between sulphur and nitrogen is a close one, with several processes within the plant requiring both nutrients to work efficiently. If you are trying to increase your nitrogen use efficiency then having an adequate supply of sulphur is a must.
Sulphur, like nitrogen, leaches readily from the soil so the source and the time you apply it is as important as the amount. Applying your sulphur at the same time as your nitrogen, split between 2 or 3 applications means that the sulphur is less likely to be lost (via leaching) before being taken up by the plant.
When it comes to timing then applying sulphur in the autumn is a no-no. Due to winter rainfall, the likelihood of that sulphur being available in the spring is minimal. Therefore applications should be in the spring, along with nitrogen using an NS or NPKS product. YaraBela Axan (27%N + 9%SO3) contains sulphur in the sulphate form, which is immediately plant-available and therefore taken up and utilised quickly.
From Yara trials, sulphur gives an average yield benefit of 0.85t/ha for wheat which at November prices gives an ROI of almost 6:1. However, we have seen responses of up to 1.4t/ha which would be a ROI of 9.5:1! For oilseed rape the yield benefit is 0.5t/ha giving an ROI of 7:1, therefore sulphur applications are well worth doing.
When it comes to applying phosphate then surely it’s simple – phosphate is phosphate right??
There are actually different forms of phosphate (P) that could be in a solid fertiliser product and they all behave slightly differently so it is useful to know the different ways they act.
Orthophosphate (Ortho-P) is found in DAP, TSP, MAP as well as most NPK compounds. Ortho-P is immediately available to the crop which means that the crop can utilise the P straight away. This is great if the crop has the ability to take all that P up in one go but the likelihood is that the biomass isn’t enough at that early spring timing to utilise all the P. Unfortunately if the P isn’t used it can become unavailable to the plant (fixed) because it becomes attached to iron or aluminium ions in the soil or precipitates out with calcium ions. This also happens quite quickly meaning that up to 40% of the Ortho-P you applied isn’t available to the plant only 2 weeks after you applied it.
Polyphosphate is our next form of P, this form takes a short while to become plant-available as it has to break down into Ortho-P first. This means it is better able to penetrate the soil and is protected initially from being fixed. Therefore products with Poly-P are able to supply P over a longer period of time without any losses.
Our final form of P is Dicalcium Phosphate (DCP) which requires citric acid to breakdown into a plant-available form. Citric acid is exuded by the plant’s roots when they are ‘looking’ for nutrients. Therefore DCP only becomes available when the plants are actively exuding acids, meaning it can stay in the soil, without fixing, until required.
Products which contains Ortho-P, Poly-P and DCP give the longest supply of phosphate throughout the growth of the crop, ensuring it is never lacking in this key nutrient. The YaraMila range of NPKS i.e. YaraMila ACTYVA S, all contain these three forms of P for a season-long supply.
Many are remembering the terrible autumn conditions last season and therefore there are lots of cereal crops that are already sown and up by now. Earlier sown crops will, of course, put on a lot more biomass in the autumn than the usual later-drilled crops (due to grass weed control). More biomass above ground also means more below ground in the root system; this large amount of growth in the autumn has the potential to deplete low levels of micronutrients in the soil.
Manganese, in particular, is an important micronutrient for crop establishment and improved winter hardiness. With many soils being deficient in manganese then early-drilled crops will benefit from an application of YaraVita Mantrac Pro at the 2-3 leaf stage to aid establishment. This can coincide with an insecticide spray and therefore doesn’t require an extra pass.
Another thing to think about is YaraVita Gramitrel. It is a crop-specific mixture of key micronutrients required for cereal crops including Mg, Mn, Cu and Zn. It is a convenient way to get these key nutrients into the crop in the autumn and can be applied 2 or so weeks after the Manganese application. Again it will coincide with an autumn pesticide application.
If your crop is going to be a later-drilled one then there will be a narrower window of application; an application of Gramitrel will be most beneficial.
In 2019/20 season a Yara trial site had applications of YaraVita Gramitrel at 2L/ha in the autumn and spring which gave a 0.55t/ha yield increase. Long-term data, however, over the past 6 seasons, shows that a 0.34t/ha yield increase is the average response; which still is a great return on investment.
Clearly the answer is yes. It is often stated that the difference between good and bad farming is 3 days ! This of course is making reference to ‘attention to detail’. It is a statement that I certainly agree with and is also a feature coming through loud and clear in the YEN project. Getting the fundamentals in place should be ahead of anything else. By way of fundamentals and crop nutrition I am thinking of ‘accuracy’ which can only be achieved with a focus on product selection. The products can be all encompassing from the laboratory you choose for analysis with its accreditation to the app you choose for crop monitoring.
However, the single biggest inaccuracy can come from the nutrient product selection. What criteria can be used to define how accuracy might be achieved? Considering fertiliser then this is all related to how you achieve accurate, even coverage of ALL the nutrients. The best way to achieve this is to ensure you purchase a product that can deliver this. If the products are single nutrients then an even size distribution with strong granules is essential, whilst multinutrient (NS, NPKS) products need to be not only even by way of granule size, but also compounds whereby each granule contains the exact analysis as purchased. From Yara then look for the YaraBela or YaraMila brands that satisfy the criteria.
What about accuracy with micronutrients? Here the single most likely cause, other than a poorly maintained sprayer, is incompatibility with other agrochemicals being applied at the same time. It is essential to check the tankmix during the preplanning process, otherwise ‘glue’ might be the unintended consequence! Good compatibility stems from the initial product development and formulation research during the design phase. Once formulated then a comprehensive tankmix list helps avoid problems out in the field. This formulation work also helps accuracy in other ways as it looks to optimise crop nutrient uptake efficiency. Yara’s range of YaraVita micronutrients are all formulated with this in mind, having surfactants, spreaders and humectants built in, with no need to add anymore to the tank.
The answer to the question posed initially is a resounding yes as already stated, and product quality should be the first step as you look to plan ahead and optimise crop performance and achieve good returns on all the investments you will make during the growing season.
When drilling winter cereals it is tempting to apply phosphate and potash at the same time but this could be a detrimental to your pocket if you’re Index 1 or above.
There are several factors as to why applying P & K in the spring is the favourable option. Soil temperatures in the autumn soon start to drop, especially if you’re delaying drilling due to grass weed control. Phosphate availability is greatly reduced in cold, wet soils therefore if you’re applying it in October/November it is unlikely to be plant available. “It’ll be there for the spring though” you might think but unfortunately this isn’t the case.
Within soil, P quickly becomes unavailable to the plant by locking up with iron or aluminium ions or precipitating out with calcium and so becomes non-labile. This happens over a short space of time, however to reverse (non-labile back to labile/soil solution) takes much longer i.e. not by the spring.
Another reason for applying P&K in the spring is because that is when the crop demand it highest. It is within a 4-8 week period March - May that the daily demand for P&K rises exponentially. Therefore in order to utilise the fertiliser in the most efficient way, apply it when the crop requires it. This will mean less chance of any being wasted or lost to the environment and the nutrient use efficiency will be improved.
Also once soil temperatures rise above 5°C in spring the plant will start to grow, however at this time the soil is still too cold for phosphate to become plant available in the soil. Therefore applying an NPKS, such as YaraMila ActyvaS or YaraMila New 18s + S, at that first timing at the end of February (weather permitting) will give the crop what it requires to kick-start spring growth without relying on soil temperatures to rise.
With harvest continuing it’s also time to think about soil sampling once crops have been taken off.
UK soils have changed a lot in the last few decades; whether it’s that 97% of soils are deficient in sulphur or the low organic matters across arable land. Therefore everyone knows the importance of taking a soil sample; but should you be investing in more than just basic soil analysis?
The basic analysis will give you P, K, Mg and pH; which is a good start but what about other nutrients and even the level of microorganisms? All these aspects are important for healthy plant growth and efficient nutrient uptake; are you unaware that your soils are low in one or more of these elements?
Yara Analytical Services have processed over 20 million samples over the years. This huge dataset has shown that after removing all the soils with limiting factors such as P < index 2, pH <6.5 and micronutrient deficiencies then there are only a small amount of soils that are sufficient in what a crop needs to grow to its full potential.
By taking a broad-spectrum soil sample you’ll know about these issues before it’s too late – when symptoms appear the yield is already taking a hit. Remember Leibig’s law of the minimum which states “A deficiency of any single nutrient is enough to limit yield”. With yields being pushed further, whilst costs savings are sought (such as P and K holidays) you could be limiting the effectiveness of any increased nitrogen applications by not improving your nutrient use efficiency as a whole.
The Solvita Test is a test of how much respiration, and therefore ‘life’, is happening in your soil. A low score shows that the soil is lacking something these microorganisms require e.g. oxygen, whereas a high score shows a good level of organisms present which improve the soil, making it more fertile.
Everyone knows that getting oilseed up and growing away as soon as possible is vital for oilseed as it faces challenges from pests at its most vulnerable stage of growth.
Ensuring there are no limiting factors that you have the ability to control, such as nutrient availability, is key to getting the crop through those first phases of growth quickly and efficiently. Hopefully you were/are able to put some NPKS fertiliser down when drilling, if not then do so as soon as possible so that you aren’t delaying any crucial growth.
Once the crop gets to the 2-4 leaf stage, an application of micronutrients is a good way of keeping that crop momentum going. The oilseed crop can put a lot of biomass on over a short space of time if conditions are right. This means there is the potential for the crop to deplete micronutrients in the soil. The easiest way to apply all of the key nutrients required by oilseed in the autumn is to use a multi-nutrient, crop-specific product such as YaraVita BRASSITREL PRO. This mix contains Mg, Mn, Ca, B, Mo and a small amount of nitrogen – all are vital to oilseed growth.
Trials conducted each year over the past 5 years have shown an average yield response of 0.33t/ha from an application of YaraVita BRASSITREL PRO both in the autumn and followed up in the spring. Using August prices for oilseed that’s over £100/ha of extra yield, making the applications very worthwhile.
There’s plenty going on at harvest time to keep everyone busy but spending some time sending off a grain sample for analysis could pay off in the long run.
Grain analysis has been available in the UK for a long time, however it is not something that would be carried out on-farm as a routine like soil or tissue analysis would. Grain analysis shows what nutrients the grain contains and therefore whether the crop has had sufficient levels of each nutrient in the growing season.
By knowing the nutrient levels within the grain, you can see whether your crop nutrition strategy worked – did the crop have everything it needed to grow to its optimum? Having this information then allows you to change your fertiliser plans for the next season i.e. if the grain results are coming back as low in potash then this could mean you need to review the amount or timing of application next season.
A good example of how to utilise the result is looking at the sulphur level within the grain. You want an N:S ratio of below 17:1 in wheat – if the ratio exceeds this then it is an indication that there wasn’t enough sulphur available to the crop.
Micronutrients are also measured in grain analysis and are, again, a good way to see whether they were low through the season and therefore causing any loss of yield. Don’t forget Liebig’s law of the minimum in which any limiting factor has the potential to stifle optimum yield.
Therefore, grain analysis is another tool in the toolbox to fine-tune nutrition to ensure that the crop is getting what it needs, when it needs it – ultimately helping towards that optimum yield.
It is well-known that there are many hurdles when it comes to establishing oilseed rape and the area will be significantly down this coming season. However, with current prices at £325/t (July 2020) and not many other break crops to choose from there will still be a decent area sown around the UK.
When getting a crop established nutrition can help get it off to a good start. If we start with a seed treatment then there are a couple of nutrients that are particularly helpful to a newly germinated seed.
Phosphorus (P) and Manganese (Mn) are both useful nutrients at the first stages of the seedling’s growth. P mobility within the soil is poor however, moving less than 1mm. Having a seed treatment that contains P means that it is in the correct place, near the seed, so that the newly developing roots can access it quickly and efficiently to give it enough P to get it growing. Mn is crucial for photosynthesis and metabolism within the plant so efficiency is decreased where Mn is deficient.
A trial looking at YaraVita Glytrel MnP nutrient seed treatment, which contains both Mn and P, showed that plant numbers doubled and root weights were over 4.5 times more in the treated side of the field than the untreated. Therefore the plants with more roots are better able to access resources and therefore established far better than the plants without the seed treatment.
The next stage of nutrition that will help establish the crop is by placing an NPKS fertiliser at drilling. When looking for a starter fertiliser for OSR a good fit is YaraMila ActyvaS (16-6.6-12.4 + 2.6% S).
There is a lot more focus on industries today to reduce their environmental impact as much as possible. With more of a spotlight being shone on agriculture for emissions, GHGs (Greenhouse gasses), being able to calculate your carbon footprint as a farmer is increasingly relevant.
At Yara we developed catalyst technology which greatly (by up to 90%) reduces emissions of N2O (a GHG) from nitric acid production. Nitric acid is required in the process of manufacturing nitrate fertilisers, therefore greatly reducing the emissions from this process means that Yara’s nitrate containing fertiliser’s carbon footprint is also reduced by 40%.
Once the fertiliser gets on to farm however it is up to the user ensure that the carbon footprint continues to reduce through best farming practice. The carbon footprint of fertiliser can be reduced at both production and application through technology and best practice.
To get the most of the fertiliser at farm level you want to get the best Nitrogen Use Efficiency (NUE) from the fertiliser that you can. This comes from product selection, timing, rate, weather conditions, crop demand, soil properties and more to ensure that the fertiliser you are applying gets to the desired location and is taken up by the crop. By ensuring all these factors are taken into account then another 10-30% carbon savings can be made by minimising losses through leaching or volatilisation.
Therefore, by product selection and best practice growers can reduce their carbon footprint by half when using Yara’s nitrate fertilisers.
By way of crop nutrition and keeping the canopy green then two nutrients stand out: magnesium and nitrogen. These two are dominant in the chlorophyll molecule, which is the key to trapping incoming solar energy. Keeping the canopy greener for longer is important to maximise the grain fill period as grain fill is the result of both redistribution of stem carbohydrate reserves and current photosynthesis.
In the oilseed crop, many trials have shown the benefit of keeping the pod and leaf canopy greener for longer. For the nitrogen application YaraVita Safe N @ 20 l/ha has been recomended. In both Yara and other independent trials these applications typically give a yield response of 0.25 – 0.3 t/ha. These results were observed in both high and low yielding crops so the return on investment should be seen as independent of the crops overall potential, a third of a tonne / ha is still worth approx. £108/ha. Magnesium can be supplied through a number of products including YaraVita Magflo 300 @ 3 l/ha which can be tank mixed with YaraVita Safe N.
In wheat then the picture is less consistent with regard to late N applications and the yield response. It is clear that extending the grain fill period through having a healthy, green canopy is important. The AHDB Wheat Growth Guide gives a benchmark of 0.18 t/ha/day of yield during grain fill so ensuring this yield development has the best chance of occurring is important. In dry years, such as 2017, then trials showed a yield response of around 0.15 t/ha associated with a late nitrogen application (GS 69-71).
Transpiration is the process by which water is drawn up through the plants from the roots and then out through the leaves as it evaporates off the leaf surface. This process is driven by the opening and closing of the stomata (small holes in the leaf surface). The principle purpose of the opening and closing of the stomata is to allow gas exchange (carbon dioxide in and oxygen out). This opening and closing is in response to light, so as daylight starts plants can start photosynthesising, and as darkness falls, stomata close to prevent further water loss. It is estimated that 90% of water taken up by plants is lost via transpiration. Whilst it could be described as an ‘unintended consequence’, it is an essential process that supplies water for photosynthesis, supplies minerals to the leaf for growth and helps cool the leaves. In an ‘ideal’ plant the process would be independent but as they are not the plant needs to be efficient at opening and closing its stomata such that carbon dioxide entry for photosynthesis is not limiting, whilst water loss is minimised to avoid wilting and structural collapse. So the issue then is what is involved in this stomatal opening and closing process? This is then where whilst it is difficult in most broadacre crops to control water supply, crop nutrition can play a part in ensuring the plant is best equipped to manage the process of water regulation. There are two key nutrients that are involved, potassium and calcium.
Whilst water supply is largely out of our control, what we can do is try and ensure the plant has adequate concentrations of the nutrients that are involved, and here I am thinking about potassium as it controls the opening and closing of stomata. Whilst soil applied potassium is inappropriate now, YaraVita Foliar Potash and YaraVita Magphos K can be options. Both will serve as a way of increasing cell potassium concentrations. Whilst not delivering the kilograms of potassium plants require during the canopy construction phase, it will help the plant regulate water loss.
There are three distinct phases during the growth of cereals, establishment (sometimes referred to as the foundation), canopy construction, and finally production. Each phase contributes towards the final yield and should have the appropriate crop nutrition management plans. During this last growing season crops have been faced with challenging conditions with waterlogging dominating the establishment phase, and drought dominating the canopy construction period. Crops are now heading towards the ‘production’ phase. The'production' phase is the period from the ear emerging, through anthesis (flowering) and finally grain fill. It is all about achieving maximum grain numbers in every ear and maintaining the duration of the 'green canopy' for good grain fill. This is reliant on a number of factors including sunlight, water supply and crop nutrition.
With regards to crop nutrition and flowering in cereals, there are some key micronutrients that need attention. Flowering in wheat will occur around 5 days following full ear emergence. It is first seen as the anthers hang out of the individual 'spikelets' that run up the length of the ‘spike’ or ear. Flowering starts from the base and moves upwards over a period of up to 10 days. Two notable features are important, having a strong healthy anther to allow for good pollen release, and good quality pollen to enable fertilisation and grain set. So what nutrients are key to focus on?
Boron is very important in a plant's reproductive growth. Boron deficiency causes poor anther and pollen development (low pollen germination and pollen tube growth), resulting in a low percentage grain set. Studies have shown that the concentration of boron is five times greater in the stamens compared to the leaf. Such a deficiency can cause a significant and irreversible decrease of floret fertility, directly reducing grain yield. Copper is another micronutrient that is associated with achieving good ear fertility. Research has shown that as you move from severe deficiency of copper supply to the developing ear, through to sufficiency, a fivefold increase in wheat flowers / plant that eventually leads to grains has been observed. Whilst not fully understood copper is thought to give strong walls to the developing anthers during flowering which allows for good opening and subsequent release of pollen and thus efficient pollination. Manganese has also been associated with flowering in cereals, where deficiency has reduced the amount of pollen and the size of pollen grains.
Yara Analytical Services data has shown over the years that cereal crops are regularly deficient in these key nutrients, especially boron and copper with many soils not able to deliver the crops requirement, making them vulnerable to not being able to fulfil their yield potential. Addressing these deficiencies at the T2/T3 timing can give those marginal gains required to maximise profitability.
New season fertiliser prices tend to bring an influx of straight nitrogen orders – but is this the correct strategy?
The first question you need to ask yourself is “Do I need sulphur?”. With 97% of soils deficient the answer is invariably “Yes”. For the crop to utilise nitrogen correctly sufficient sulphur is required due to the close relationship between the two nutrients.
When applying sulphur it should go on little and often, the same way you would apply your nitrogen, because it has the same leachability characteristics. Therefore this will also affect your product choice, you need a product that combines both nitrogen AND sulphur. It is also in the sulphate form which is plant available and therefore the crop can utilise it quickly. Elemental sulphur has to undergo an oxidation process before it becomes plant available which is weather-dependent and could take up to 8 weeks.
The next question is “Do I need P&K?” - applying fresh P & K with the first nitrogen timing means that the crop gets a fresh dose of plant-available nutrients when soil temperatures are perhaps not high enough for the crop to utilise what may already be in the soil. This also means that the phosphate and potash are there when the crop enters the phase of rapid growth and is at its highest demand for nutrients. Yara trial work has also shown that using an NPKS compound all the way through the season usually has a yield benefit over other programmes therefore making it a very simple way of fertilising.
The final question is “How far am I wanting to spread to?”. If more than 30m then a granular product is required due to its increased strength characteristics, meaning it can spread safely and evenly well beyond 40m bout widths.
These three questions will ensure you don’t end up with a shed full of a product that isn’t suitable for your needs come next spring.
Growers often say they’re growing a milling wheat variety and if it reaches spec then that’s great, but if it doesn’t then it doesn’t matter. Premiums are at £15/t (at the time of writing this) so should some more thought be given to those milling varieties? Hitting the protein target that millers are looking for ideally requires a separate application of nitrogen after the flag leaf final-dressing.
The application needs to be separate in order to ensure the nitrogen goes towards building up the protein level within the developing grain. Nitrogen source, rate and timing are all important when trying to boost the protein, as we need to be sure the nitrogen is utilised correctly in the plant.
Applying about 40kgN/ha (e.g. 160kg/ha of YaraBela Axan) at growth stage 51 (which is the start of ear emergence) can increase grain protein levels by up to 1%. This is possible to achieve without compromising the yield. Yara trials showed that the separate application later in the season gave a boost in both yield and protein when applied at end of booting/start of ear emergence.
However, if the plant is deficient in certain micronutrients you’re at a disadvantage. Manganese and zinc, in particular, are important in the metabolism of nitrogen. If nitrogen metabolism is improved then this increases the amount of nitrogen that is incorporated into the developing proteins in the grain. Trials work, again, has shown that an application of zinc at T2 timing can increase grain protein by up to 1.4%! Therefore it is important to ensure there’s no zinc deficiency if aiming for the milling premium - an application of YaraVita Mancozin or straight YaraVita Zintrac at T2 will prevent this.
There are so many fertilisers to choose from that sometimes it’s easy to focus on the price rather than the quality aspects. With increasingly wider spreader bout widths your choice of fertiliser might not be up to handling them.
Firstly is it a blend or a true uniform compound that you’ve chosen? There are issues surrounding blends such as segregation, inconsistency of analysis, and uneven spread patterns. These can all lead to uneven crop growth and striping in the field. Choosing a true uniform compound will eliminate these issues as each granule/prill has the identical analysis.
When applying compound fertilisers at wider bout widths you need to take factors such as the strength of the granules/prills into account. Do you need to spread more than 30m? If so then you will need to consider using granules, however not all granules are equal.
The ‘hardness’ of the granule is important, especially for those wanting to spread 36m+. If you imagine how fast the vanes are moving and therefore what speed the granule is hitting them then you can see why the hardness is important. A granule/prill that has a low strength score is more likely to shatter on impact with the vanes and be turned into dust. Dust doesn’t tend to spread very far…
If the granule has a high strength score then it is less likely to shatter and therefore will be spread to the desired width. This means that the crops will be given a uniform application of the product across the bout width and in turn this will mean even crop growth. As an example YaraBela Extran 33.5%N has a hardness score of 8-9.5 and Yara trials have spread it to over 50m.
The bulk density is another important factor, the higher the bulk density the further the fertiliser will travel and be less affected by wind. Imagine hitting a dense golf ball versus a hollow ping pong ball – you know which one would travel the furthest.
Finally we have had some more settled weather and with that no doubt you are thinking about drilling some spring crops.
Success for spring crops comes from going into good soil conditions and then getting up and growing as quickly as possible, this means once it’s drilled the momentum needs to be kept going through the key stages.
Due to the speed that spring crops can grow when the soil temperature increases, it’s vital to ensure they have enough nitrogen in the seedbed but that doesn’t mean all of it. Trials work conducted by Yara shows that there is a benefit to splitting the nitrogen application, a ratio split of 60:40 or 70:30 gives a consistent yield benefit when comparing it to 100% at drilling. This means that the crop has access to potentially more of the total nitrogen applied where some could be lost through i.e. leaching if all applied at once.
However, don’t leave it too late! You want to get back with the remainder of the split before the crop goes past the 3-leaf stage and definitely before it starts to extend. Trials on spring wheat show that the yield penalties from applying the second dressing of nitrogen after growth stage 30 are substantial, with as much as 0.71 t/ha being lost.
Ideally the 60 or 70% in the seedbed should be an NPKS/NS fertiliser such as YaraMila Actyva S, to give the crop the best chance of establishing well and the likelihood to succeed.
Don’t forget that micronutrients are just as important in spring crops, especially because their growth rate is so rapid. This makes it especially difficult to get the sprays on because the window of opportunity can be narrow when they’re moving through growth stages in days sometimes. Getting the key micronutrients on spring cereals – Mg, Mn, Zn, Cu and B is important as these are also the ones we see in the labs as highest in terms of deficiencies in tissue tests.
With a very difficult Autumn and Winter it is hard to know what nutritional value soils will have for crops this spring.
Excess winter rainfall and waterlogged conditions potentially means that soils are at an all-time low in terms of nitrogen and other nutrients. Knowing to what extent this is true in your soils can often be a challenge. Using tools and services to take the guesswork out of nutrient applications is the best way to ensure optimum plant growth.
For nitrogen applications, the 3rd dressing is where potential improvements in nitrogen use efficiency (NUE) can be made. The first and second applications of nitrogen can be pretty much the same rates year on year - give or take. It’s the 3rd at BBCH 37-39 (flag leaf) that can be tricky. This year in particular will be difficult to manage as we don’t know how much nitrogen the crop will have got from the soil – it could be much less than a “regular” year.
Using a tool like the Yara N-Tester will make this decision easy. The N-Tester looks at what nitrogen levels are in that crop at that particular time – in other words the crop is telling you exactly what it requires. It could be that the crop requires a little more or less than the N you had planned, either way the crop is getting a recommendation for what it needs for optimum growth at that time.
Another device that can help with nitrogen recommendations is Yara’s Atfarm. This is a way of monitoring the biomass of a crop and creating a variable nitrogen application map. It’s based on the NDVI as well as the algorithm that is used in Yara’s N-Sensor technology, thereby making it possibly the most accurate satellite-based nitrogen mapping tool on the market.
Whichever way you choose to monitor your crop nitrogen levels, this year will be an interesting one due to the potential over-winter losses of nitrogen, and if it’s not something you’ve done before I urge you consider it this year.