Influence of Mineralogy on Potassium Availability in Indian Soils

摘要

The potassium dynamics in soil is known to be governed by the mineralogy of the clay fraction of soil. An attempt has been made to relate the potassium (K) status, especially the K supplying capacity of soils to such mineralogy. It is evident that not only the mere presence of the relevant clay minerals, but also the nature and the weathering history of the mineral phase are important factors influencing potassium release. The imbalance in NPK fertiliser application in agriculture has been discussed, with special emphasis on K. Potassium imbalance far outweighs such imbalance in respect of N and P. This leads to considerable K mining from Indian soils which is undesirable in the long-term. In this context, the relevance of the so-called "ideal (or optimum)" ratio of NPK fertiliser application to crops and cropping system, irrespective of the soils and the crops, has been examined. The need for a balanced approach, taking due cognizance of soil properties, its nutrient (K) supplying capacity and nutrient (K) requirement of crops in site-specific potassium management mode has been highlighted to improve the productivity of crops.