A sound resource management strategy is fundamental to ensure sustainability of agricultural production. Soil as a resource is the key determinant that has to be managed in a scientific manner in order to keep it sustainable. Rational use of soil resources, based on its potential is essential for an economically viable and ecologically sound agriculture. Input management decisions on macro and micro level should be based on scientifically evolved database on soil resource so as to make it effective.

Addressing the problems in the agricultural production sector and livelihood opportunities of rural poor formed the basic strategy of the development plan under the Rashtriya Sam Vikas Yojana of the government of India. Palakkad district was included under this programme. Rice being the important food crop grown in the district, programmes were chalked out to improve the productivity of rice and sustainability of rice cultivation system.

Effective interventions in soil resource management and utilisation for augmenting production through scientific resource use were proposed under the project on “Soil Fertility Mapping and Nutrient Management Plan for Rice Soils of Palakkad”. This formed a part of the comprehensive project on “Detailed Land Resource Inventory for Precision Agriculture in part of Palakkad District with special Reference to Rice Cultivation and Nutrient Management Plan”. The project objective was to give guidance on nutrient management based on authentic soil fertility data. This project envisaged generation of soil fertility data base and their interpretations for the major rice-growing tracts of Palakkad district with a view to assist farmers, planners and research workers.

Participating Institutions

1. National Bureau of Soil Survey and Land Use Planning (ICAR), Regional centre, Bangalore
2. Kerala State Soil Survey Organisation, Department of Agriculture, Government of Kerala
3. Regional Agricultural Research Station (KAU), Pattambi, Palakkad, Kerala

Selection of Area

Extent of rice cultivation was used as one of the criteria for selection of area under the project. Representative areas from three major agro ecological zones in the district were also included. Thus 42 Panchayaths having more than 25% geographical area under rice representing three agro ecological zones in the district were selected for sampling. Details are provided in Table 1.

Soil sampling

Detailed soil survey and surface soil sample collection were carried out by NBSS & LUP in 12 Panchayaths and by KSSO in the remaining 30 Panchayaths. Surface soil Samples were collected from plots under each survey number. Collected samples were handed over by these agencies to RARS, Pattambi for processing and estimation of available nutrients.

Processing of samples

The surface samples were air-dried, clods were crushed using wooden pestle and mortar and sieved through 2 mm sieve. Plant residues, gravel and other foreign matter retained on the sieve were discarded. For certain type of analysis (Eg. organic carbon) it was necessary to grind the soil further so as to pass it through sieves of finer mesh size (0.5 mm).

From each sample weighed sub-samples were drawn for analysis of individual nutrients. 10g sub-samples were used for estimation of pH and Electrical Conductivity. For estimation of available Phosphorus and Potassium, separate 5g sub-samples were drawn. Based on the pH, 2 or 10 g sub-samples were used for micronutrient analysis (2 g for acidic soils and 10 g for neutral-alkaline soils). For organic carbon estimation, 1 g of sample sieved through 0.5 mm sieve was used. 53,000 samples were analysed through more than 5,30,000 estimations on pH, Electrical conductivity (EC), Organic carbon, available Phosphorus (P), available Potassium (K), and available micro nutrients i.e. Iron (Fe), Manganese (Mn), Zinc (Zn) and Copper (Cu). Selected samples were analysed for Boron (B) and Sulphur (S).