Too much fertiliser use has ruined soil health: study

The indiscriminate use of fertilisers, insecticides and pesticides over the years has led to deterioration of soil quality and crop productivity in India. According to a study conducted by the central soil water conservation research and training institute (CSWCRTI), Dehra Dun, about 1 millimetre of top soil is lost every year due to erosion. This leads to a total soil loss of 5,334 million tonnes annually, at an average rate of 16.4 t/ha/yr.

Wrong irrigation practices are also responsible for soil erosion. In a written reply to a question in Rajya Sabha, minister of state for agriculture KV Thomas said that excessive canal irrigation may lead to secondary salinisation, thereby affecting soil and crop productivity.

To another question, agriculture minister Sharad Pawar said that the imbalanced use of fertilisers coupled with low addition of organic matter and neglect of micro and secondary nutrients over the years has resulted in nutrient deficiencies and deterioration of soil health in many parts of the country, particularly in the intensively cultivated Indo-Gangetic plains.

According to a study published in the Journal of Soil and Water Conservation, the annual erosion rate due to water is less than 5 Mg/ha/yr (2.2 tons/acre) for dense forest,  cold desert regions and arid regions of India. Wind erosion is also active in the Indian desert situated in the northwestern part of the country.

Indo-Gangetic plains, including salt-affected lands of Punjab, Haryana, Uttar Pradesh, Bihar, and West Bengal show moderate erosion rates (5-10 Mg/ha/yr). The areas revealing severe erosion —- more than 20 Mg/ha/yr —- include the Shivalik Hills, northwestern Himalayan regions, ravines, shifting cultivation regions, western coastal ghats and the black cotton soils areas of peninsular India. The remaining parts of the country lose between 10-20 Mg/ha/yr.

According to Pawar, to curb this the government had launched the National Project on Management of Soil Health and Fertility in 2008 to promote a soil test based on judicious use of fertilisers for improving soil health and productivity.

The scheme includes setting up of new soil testing laboratories, strengthening of existing soil testing laboratories, training of soil testing laboratory staff/extension officers/farmers, field demonstrations on balanced use of fertilisers and promoting use of organic manure, soil amendments and micronutrients.

Meanwhile, the agriculture ministry on Tuesday released new guidelines on the National Mission on Micro Irrigation (NMMI) to enhance efficiency in water use, productivity in crops, and provide an answer to water salinity and water-logging issues.

The revised norms and the incorporation of additional components would incentivise further investments in water-saving technology to increase the gross area under cultivation.
NMMI is expected to boost converge of micro-irrigation activities under major government programmes such as National Food Security Mission (NFSM), Integrated Scheme of Oilseeds, Pulses, Oil palm & Maize (ISOPOM), Technology Mission on Cotton (TMC) etc., for increasing water use efficiency, crop productivity and farmers income.