In this month’s newsletter published by the Potash Development Association (PDA), it is said that Justus von Liebig’s Law of the Minimum states that yield is proportional to the amount of the most limiting nutrient, whichever nutrient it may be. Nitrogen is the nutrient that most frequently provides the largest response, suggesting that this is usually most limiting. However, the plant-available potassium status of a soil has a considerable influence on the uptake of nitrogen by crops. Potassium is very important in the relationship between water and crop growth through helping to regulate the amount of water within a crop. Potassium has an essential role in plant disease resistance, probably the most effective of all the nutrients.
High yielding crops need large supplies of both nitrogen and potash and it is no accident that the addition of N stimulates the need for, and uptake of, K. When used carefully, nitrogen is usually the greatest agronomic stimulant to crop growth. But for it to be used efficiently in crop production and play its full role in increasing yield, a crop must also have access to, and take up, an adequate amount of potassium from the soil. More