Soil Fertility Related Constraints to Crop Production in Kerala

Abstract

Stagnation and decline in productivity of most of the agricultural and plantation crops in Kerala, despite the genetic improvements in crop varieties and heavy external inputs of fertilisers and pesticides, prompted the Kerala State Planning Board to embark on a massive project to identify and map the soil related constraints to crop production. Highly weathered laterite soils, covering most of the state, are relatively infertile, acidic, gravelly clay depleted of basic cations and possessing low water and nutrient retention capacity. In order to assess the soil fertility in the state and to elucidate the soil related constraints nearly two lakh composite surface soil samples were collected from farmer’s fields all over the state and analysed for soil reaction, macro, secondary and micronutrients. Extensive acidification of the soils, build up of high levels of phosphorus and deficiencies of calcium, magnesium and boron were found to be the major soil related constraints in the state.