Soil Fertility Evaluation under Different Land Use System in Tropical Humid Region of Kerala, India

Aims: To know the fertility status of soils of the Elamdesam block.

Place and Duration of Study: Soil samples were brought from Elamdesam block, Idukki district, Kerala, India in the year 2016 and laboratory characterization was done in National Bureau of Soil Survey and Land Use Planning, Regional Centre, Hebbal, Bangalore.

Methodology: Based on the different land use type, composite soil samples were collected randomly from 0 to 20 cm depth. Soils were processed and analyzed for soil reaction, electrical conductivity, organic carbon, available major (Available NPK), secondary (Ca, Mg and S) and micronutrients (Fe, Mn, Zn and Cu, B). Mean values for all the nutrients under different land uses were calculated for comparison. Soil testing rating chart was further used to separate soils for interpretation under various categories.

Results: Results revealed that soils are very strongly acidic in reaction. Organic carbon content is high in all samples. Phosphorus content varied from low to medium and potassium content was very low to medium. Available calcium and magnesium were very low and sulphur was medium. The copper content was adequate and zinc and boron were a deficit. Among land uses, pineapple land uses recorded highest EC (0.10 dS m-1), available P (82.19 kg ha-1), K (196.32 kg ha-1) and S (11.49 ppm) whereas paddy soils recorded highest pH (5.08), Ca (264.33 ppm), Fe (98.70 ppm), Cu (3.95 ppm) and B (0.32 ppm). Similarly, rubber growing soils have the highest Mn (6.92 ppm) whereas oil palm soils have highest organic carbon (2.80%). Banana land uses the highest EC (0.10 dS m-1) and Zn (1.26 ppm) and coconut soils have highest Mg (34.96 ppm).

Conclusion: Soil fertility is one of the important factors controlling the crop yields. There is a need for correcting deficiencies of nutrients for sustained crop production. Thus, evaluating and assessing nutrient status is a must under various land use systems in order to recommend soil and crop specific nutrients.