A critical deficiency of boron, exceedingly high levels of phosphorous, and high acidity are eroding soil fertility in farms, a State- wide survey coordinated by the Kerala State Planning Board has revealed.
The analysis of 1,17,251 soil samples collected from panchayats across the State showed the serious nature of soil acidity. The interim result of the study revealed that 59 per cent of the samples were deficient in boron, while 76 per cent were low in magnesium, and 40 per cent low in calcium.
Boron deficiency can lead to stunted growth and deformities in plants while low magnesium levels result in yellow leaves and fruit rot. Calcium deficiency is responsible for impaired root growth and fruit rot.
Fifty per cent of the soil samples were found to be high in phosphorous and 18 per cent high in potassium while 23 per cent of the samples were low in nitrogen, 26 per cent low in sulphur, and 12 per cent deficient in zinc.
Phosphorous run-off from farms is a major source of contamination of water bodies.
It promotes excessive growth of algae and weeds in streams and lakes, affecting fish and other aquatic organisms. Washed out to sea, the primary nutrient also pollutes the marine environment, often triggering harmful algal blooms.
Boron was found to be deficient in 211 of the 270 panchayats from where soil samples were collected and zinc deficient in 59 panchayats, while phosphorous content was in excess in 141 panchayats.
The study report recommends the application of borax and zinc sulphate through soil or foliar spray to alleviate the deficiency of boron and zinc. It also advocates a 50 per cent reduction in application of phosphatic fertilizers to address the excess of phosphorous in soil. Another major recommendation is regular liming practice to combat acidity and alleviate calcium deficiency.
The project involving 14 institutions and 27 laboratories in Kerala, is aimed at developing soil- based plant nutrient management plans for the 999 panchayats in Kerala.
Over 2 lakh soil samples will be analysed for micro, macro, and secondary nutrients. Plant nutrient management plans have been formulated for 350 panchayats and soil health cards distributed to farmers.
The Indian Institute of Information Technology and Management Kerala (IIITM-K) has developed a software for soil data analysis and launched a dedicated portal named ‘keralasoilfertility.net.’
The National Bureau of Soil Survey and Land Use Planning (NBSS&LUP), Bangalore, is coordinating the scientific activities.
According to P. Rajasekharan, Chief (Agriculture), Planning Board, the soil-based intervention was aimed at enhancing returns for farmers by cutting down on input costs and boosting productivity. He said the data on fertility status and nutrient management would help them rationalize the use of fertilizers.
KSPB has initiated steps to equip the laboratories under the Department of Agriculture with atomic absorption spectrophotometers to analyse micro nutrients.T. Nandakumar