Agrotechnology

Short-term effects of integrated nutrient management options on soil nutrient status and soil microbial properties in soils under rainfed post rainy Sorghum (Sorghum bicolor (L.) Moench)

4^th International Conference on Agriculture & Horticulture

July 13-15, 2015 Beijing, China

Chourat Sudhakar

Posters-Accepted Abstracts: Agrotechnol

Abstract:

A field study was carried out at Agricultural Research Station, Tandur, Telangana during 2011-12 and 2013-14. The aim of the study was to determine the short-term effects of contrasting integrated nutrient management regimes on sensitive soil nutritional and microbial parameters under an annual post-rainy season rainfed Sorghum (Sorghum bicolor) grown on vertisols. The nutrient management regimes employed in the study were pre-sorghum green manures (Sesbania, Sunnhemp and Greengram) integrated with chemical fertilizers; N-levels (0, 20,40 and 60 Kg N ha-1). The study also included a control where no fertilizers, whatsoever were applied. The variables studied were soil N, P and K buildup and soil microbial status after conclusion of the experiment. The influence of integrated nutrient management regimes was most evident soil nutrient status and soil microbial properties. After three years of study, pre-sorghum incorporation of Sesbania improved available N (from initial 205 to 224.6 Kg/ha.), P2O5 (from initial 19.0 to 25.3 Kg/ha.) and K2O (from initial 375 to 427 Kg/ha.). Application of each incremental dose of N from 0 to 60 Kg/ha significantly improved the available N (from initial 205 to 218.0 Kg/ha.) and K2O (from initial 375.0 to 406.2 Kg/ha.). However, available P2O5 linearly declined due to application of graded levels of N from 0 to 60 Kg/ ha from 22.9 to 19.7 Kg/ha. Similarly, improvement in soil microbial status also found significant due to incorporation of presorghum leguminous crops at the end of three year study. Pre-sorghum incorporation of Sesbania improved the Actinomycetes counts (from initial 132 to 297�?104CFU g-1 of soil), Bacterial colonies (from initial 72 to 164�?106 CFU g-1 of soil). However, Fungi remained almost unchanged with Sesbania incorporation (from initial 47 to 46�?102 CFU g-1 of soil). While, application of each incremental dose of N from 0 to 60 Kg/ha has significantly reduced soil microbial counts of Actenomycetes, Bacteria and Fungi significantly. The strong effects of nutrient management regimes implied that soil biochemical/microbial parameters are sensitive enough to detect changes in soil quality even in the short-term.