Peer review

Potassium (K) is an essential nutrient element and its mportance in crop production has increased with the intensification of agriculture. Crop residues usually contain about 80% of total K uptake by a crop and these can supply about 7 million tonnes (Mt) of K annually in India. There is a wide range in actual nutrient contents in crop residues and organic manures, and thus samples should be analyzed for more accuracy. Net positive or small negative soil K balances have been observed when crop residues are returned to the soil. Potassium in most crop residues and other organic sources is immediately released in soil and becomes available for crop use. Residue management is an important component of conservation agriculture systems because surface residues help to reduce water loss, soil erosion, increase soil organic matter, and recycle plant nutrients. The fertility of soils is related to the quantity and quality of crop residues returned and the rate of their decomposition. Rate of K release from crop residues in soil is quite fast and a significant proportion of K can be lost through leaching in coarse-textured soils, particularly under rice-wheat system. We need an improved understanding of how crop residue management affects K cycling and different K-pools in the soil. To obtain a more meaningful picture of the changes taking place in the different fractions of soil K after long-term recycling of organic materials in the root zone, soil layers deeper than conventionally considered 0-15 cm should be taken into account.

Wheat CRP FP4 - Sustainable intensification of wheat - based cropping systems

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