Agronomy Advice

Let crops make better use of limited nitrogen

A poor or compromised root system, caused by phosphate deficiency will not allow plants to make the best use of limited nitrogen. Giving crops a boost from foliar phosphate together with zinc to help keep the plant healthy is the best way to build a big and healthy root system which will then have benefits right through the season.


Foliar phosphate and zinc – let crops make better use of nitrogen
Foliar phosphate and zinc – let crops make better use of nitrogen
Low availability of phosphate often limits root growth

Nutrient deficiencies, especially phosphate, often limits root growth and development, thus limiting a crop's ability to take up nitrogen and other nutrients. Such a limitation becomes even more important when nitrogen supply is limited and nitrogen use efficiency needs to be maximised. This restricted nutrient uptake further limits root growth and development, making the plants more vulnerable to other stresses as the season progresses.

To help plants make the best use of limited nitrogen it is important to focus on those nutrients that are most likely to be limiting root growth and development, particularly phosphate. The processes in the soil that determine how much phosphate is in the ‘available pool’, which is the one that the plants draw from as they require it, are temperature-dependent i.e. cold soils reduce soil phosphate availability.

Poor rooting makes nutrient uptake less efficient

The developing cereal plants grow at these cold temperatures (approx. 5 – 6 °C), thus potentially exhausting this supply. A poor supply of phosphate restricts the conversion of solar energy into the plant's chemical energy (ATP) that is used during photosynthesis to drive new growth and development.

To help overcome this limitation there are actions that can help. Firstly, consider how the root system can be repaired, or improved to enable better access to nutrients that are available. One way of repairing and building a larger root system is to apply some phosphate through the leaves. Research has shown that an application of foliar phosphate can significantly increase the root size/area

Foliar application of phosphate improves root growth

This 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/repair, it builds in resilience, enabling the crop to overcome further potential stress points such as drought during the spring and summer months.

Effect of foliar phosphate on root growth

Zinc deficient plants tend to be more susceptible to disease

Zinc has been shown to reduce the incidence of soil-borne diseases such as (Rhizoctonia cerealis) which also causes sharp eyespot. In addition to causing yield losses directly, these root diseases also restrict the ability of a plant to efficiently take up nitrogen and other nutrients. Making sure a crop is not zinc deficient is one way to maintain plant health and helps to set the plant up for the spring.

YaraVita Crop Boost is recommended on on all cereals, not just maize

YaraVita Crop Boost contains high concentrations of phosphate together with zinc, magnesium and potash for foliar application to all cereals, not just maize. It provides readily available phosphate at a time when crops cannot source sufficient from cold soils and also provides important zinc and magnesium which are often deficient in cereals. Because it is foliar applied it is very quickly taken up by the crop for immediate use.

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