Agronomy Advice
July 01, 2021

Is there a better alternative to monopotassium phosphate for soft fruit growers?

By: Giz Gaskin

Monopotassium phosphate, otherwise known as MKP is a product synonymous with fruit production that is widely used, primarily as a flower boosting green fruit supporter. However, at this point in time, MKP is sometimes difficult to get hold of, so many growers are asking if there is a better alternative.

Is there a better alternative to monopotassium phosphate
Is there a better alternative to monopotassium phosphate

Why is MKP in short supply?

The reason behind the shortage lies with international politics. Last month the EU imposed sanctions on Belarus following the interception and forced landing of an international flight followed by the arrest of a prominent journalist and anti-government critic. So what does this have to do with UK fruit? A little known fact is that Belarus is a major global supplier of raw mineral phosphorus fertiliser grade minerals, so with EU sanctions and potentially a USA embargo, supplies of commodities out of Belarus are looking quite tight. There is a restriction in supply, meaning an increase in demand and a subsequent increase in prices. All of which have a knock-on effect further downstream on phosphorus heavy fertilisers, like MKP. This disturbance in the supply chain has caused a global reduction in supply and price increase ex Belarus, followed by consequent phosphorus fertiliser price increases in general.

Yara previously supplied monopotassium phosphate as YaraTera Krista MKP, however, due to the problems with supply, this is no longer easy to get hold of and an alternative is needed. 

So, what can we do?

Fortunately, there are other options. Although monopotassium phosphate has been widely used historically in UK fruit, much has changed in fruit production since MKP was first introduced and even if it were still available it might not be the best choice.  Instead, we would recommend you take a look at integrating the Yara Kristalon range into the current fertigation program as an alternative for the less available and becoming more expensive MKP, for the following reasons. Specifically, we recommend YaraTera Kristalon Brown, although YaraTera Kristalon Scarlet is also a good alternative.

Using Kristalon Brown in place of MKP is not solely about the lack of phosphorus. Kristalon Brown also contains all of the micronutrients and a low percentage of nitrogen too, which means it can be integrated into an existing program and keep the new program in balance. Kristalon Scarlet can do the same, but Kristalon Brown is lower in N at just 3%.

How does Kristalon compare to MKP?

Krista MKP was all about supporting the flowers and green fruit as a primary use, with phosphate also for supporting the roots in bag production. Kristalon Brown by contrast has less phosphate than MKP and a higher ratio of potassium, so to use it well the fertigation programme will need to be adjusted slightly, although there are a few trade-offs in the thinking.

Flowering & fruiting

Kristalon Brown is a great flower and early fruit supporter in its own right as good as MKP and also free from chlorine which makes managing EC far easier.


Kristalon Brown is not MKP there is some root support but the focus is more about top quality. Since there will be less phosphate for root growth, the plants will need to work harder. However, much of the MKP debate is historic and based on older varieties like Elsanta and Sonata. Strawberry and indeed raspberry/blackberry varieties have changed significantly since MKP was first introduced. The new verities are more vigorous and expected to work harder in the rooting zone so this is an option now, whereas in the past it was not. Also, there are other inputs that can be introduced to the rooting zone, such as YaraVita Actisil and or YaraVita Biotrac which will help the root mass develop and grow stronger in the absence of MKP.


Kristalon Brown has a full complement of micronutrients available and only 3% N, where MKP has nothing in micros. This means that Kristalon Brown is a more precise formulation designed to give exactly what the plant requires. Where MKP is purely about macro inputs. With the inclusion of these micros, thinking about using Kristalon Brown brings more advantages to overall crop health as a fuller product than had been the case with MKP.


Whilst Yara Kristalon Brown is a good alternative to YaraKrista MKP it is actually a much more complete product with several advantages over the traditional MKP. This used to be reflected in the price, however with the change in the supply situation this is no longer the case and now we see a comparative pricing structure between the Kristalon range and Krista MKP based largely on phosphate content which negates any price difference between the two products and may on some days lend Kristalon Brown in favour over Krista MKP.


Yara Kristalon Brown is a more widely used product globally, which means it is more readily available than Yara Krista MKP. Yara Kristalon Brown (and Scarlet) are available at the moment with forward supplies looking good.

To round up the situation, if your supplies of Yara MKP are looking tight, Yara would recommend a shift into Yara Kristalon Brown which can achieve similar or better results than Yara Krista MKP. While the Phos issues are resolved, though once you try Kristalon, you may find Brown’s ability to boost the flowers and promote overall crop health, a far better solution than using MKP plus other singles.

Check out our strawberry fertigation programme


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Strawberry fertigation and nutrition advice
Strawberry fertigation and nutrition advice

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