The world understands one of the great challenges ahead remains the need to dramatically increase food crop production to sustain our future global populations.
In agriculture, this is not only driving the use of new methods and inputs to help grow crop yields, but also strategies to reduce elements that can limit production.
In the crop nutrition industry, one of the recent focus areas has been the negative role chloride plays in crop production and, hence, the use and impact of potassium sources with high chloride content compared with using the more beneficial potassium nitrate.
Tal Shani, soluble fertilisers marketing manager with the world’s leading supplier of potassium nitrate, Haifa Group, says research has indicated alternative potassium sources can increase salinity by nearly 50 per cent compared with potassium nitrate, and with some sources it is close to 100 per cent.
“Chloride is required by plants, but only in small quantities and is generally satisfied by the chloride levels that already exist in soils or that is added via fertiliser treatments, irrigation water applications or rainfall, particularly in coastal areas,” he said.
“Chloride levels in plant tissues have been shown to be 10 to 100 times higher than what is required for ideal growth, indicating the widespread incidence of high chloride levels in soils, which causes a range of detrimental effects.”
He said excess chloride in soils is associated with increased soil salinity and becomes toxic to plants, damaging crop development and soil systems.
“Applications of potassium chloride, which are still common in cropping systems today, continue to build chloride (or salts) in soil and in the plant root zone, which then also blocks the uptake of essential nutrients like nitrate and sulphate that contribute to healthy crops and foods.
“Using potassium chloride adds 760 grams of chlorides for every kilogram of potassium applied to soil, whereas potassium nitrate is virtually free of detrimental chloride.
“Furthermore, the addition of chloride to soils then requires intensive, extra irrigation to prevent the accumulation of salts in the root zone, countering the ongoing push to enhance our water use efficiency. “
Mr Shani said a key benefit with potassium nitrate was that under excessive chloride and saline conditions, the nitrate component helped to reduce the harmful effect of chloride and the potassium component counteracted the damaging effects of sodium.
“Haifa Group introduced potassium nitrate by combining potash and nitric acid and it continues to be at the forefront of new application developments with the fertiliser.
“The company’s potassium nitrate fertiliser contains 100per cent plant nutrients, ensuring no residues to contaminate soil or groundwater.”
Mr Shani said effective synergy between the nitrate and potassium, enhanced uptake of the nutrients by plant roots and it also prevented adsorption of the latter to soil particles, thereby keeping it available for uptake over a longer period.
Due to its low salt index, there is also no need for extra irrigation, importantly saving water, and Haifa Group’s potassium nitrate can be safely mixed with all water-soluble fertilisers.
A range of trials in different crops and locations have consistently demonstrated the benefits of potassium nitrate compared with other potassium sources.
In one of Haifa’s own trials, where potassium nitrate was compared with potassium chloride in greenhouse-grown tomatoes on a sandy loam soil type, yield was 17.4 per cent higher where the potassium nitrate was applied.
The trials are continuing to reinforce the benefits of potassium nitrate to growers and the risks of using alternative potassium sources, which, although a lower cost investment, are detrimental to crop production, soil systems and their returns.
