Abstract

The soil quality and fertility in the country are of utmost importance. Declining soil fertility is one of the primary factors that directly affect crop productivity, and fertilizer use is a key factor in order to ensure soil fertility and productivity. Potassium (K) depletion in soil is also a major factor in declining soil fertility. Degradation of soil due to significant nutrient demands by crops and imbalanced fertilizer application is common in the arable lands of India. While practices of nitrogen (N) and phosphorus (P) application have been established and disseminated, K crop and soil requirements are largely ignored.

Rice and wheat are among the most important crops in India both from the perspective of food security and export. However, productivity of these crops in India is low compared to their yield levels. To evaluate the K response in these two critical crops, and to demonstrate to farmers the increased yield and profitability with application of muriate of potash (MOP) on K depleted soils, a project – the Potash for Life (PFL) project – was launched. This study aimed to evaluate and demonstrate the principal contribution of K application in increasing wheat and rice yield and profitability, and to raise the awareness of stakeholders and growers towards vital need to adopt balanced and K-inclusive fertilization regimes. Three identical plots were grown with the selected crops side by side. Besides optimum level of N and P, three levels of K, i.e. 0, 40 or 80 kg ha^–1 were applied. A significant and positive effect of K levels was observed in both wheat and rice crop. The average yield increase was statistically significant and was around 571-599 kg ha^–1 (11-15%) in wheat, and 286-728 kg ha^–1 (4-11%) in rice. It was concluded that the plant available K in the soil K is significantly lower than the plant demand for wheat and rice production indicating the necessity for which means that K fertilization to improve agricultural productivity.

Keywords: Potassium response, rice, wheat, Vertisol, critical limit.