Temperature, Moisture and Biological Activities Affect SOC Decomposition Under the Influence of Fertilizer and Manure.

Temperature, moisture and biological activities affect SOC decomposition under the influence of fertilizer and manure M. C. Manna1, P. Bhattacharrya2 , T. K Adhya2, R. S. Sisodia1 and A Subba Rao1 1Indian Institute of Soil Science, Bhopal-462038 (M.P.), India 2Central Rice Research Institute, Cuttack – 753006, Orissa, India. Abstract Interactive effect of temperature, hydrological regimes and microbiological activities on soil carbon decomposition was investigated in a Vertisol under wheat-soybean crop rotation. Field treatments included control (unfertilized), 100% NPK, 100% FYM, 100% NPK+FYM and 100% NPK+FYM+Crop residue (CR). Surface soil samples at 0-15 cm depth were collected after harvest of soybean during winter, 2008. Soil samples were incubated for 90 days under different hydrological regimes including 50% MHC, 100% MHC and submergence (8 cm standing water) at 35oC and sampled at 3, 10, 20, 40, 60 and 90 days after incubation for analysis of active and slow pools of C. The particulate organic matter carbon (POM-C) content varied from 14.7 to 28.4% of TOC and was lowest in unfertilized control. After 90 days of incubation, POM-C fraction (% of TOC) decreased substantially from 41.3 - 65.3 at 100% MHC, 34 - 59.3 at 50% MHC and 23 – 45 under submerged conditions. CO2 evolution was relatively low under submerged conditions than at 50 or 100% MHC and was highest under field capacity. CO2 evolution was highest in 100% NPK+FYM+CR treatment followed by 100% FYM, 100% NPK and 100%NPK+FYM in that order. Under 100% MHC, the bacterial respiration was comparatively low than fungal respiration, whereas under submerged condition bacterial respiration was higher than fungal respiration. The water soluble-C and acid hydrolysable-C also followed a similar trend to that of CO2-C evolution. This study clearly indicated that emission of gaseous-C was significantly increased due to exhaustion of the labile pools of carbon under 100% MHC, whereas integrated nutrient management practice of 100% NPK+FYM can minimize it. Visa Card ( Dr.Himangsu Pathak) Name : Dr. Himangsu Pathak VISA CARD No.: 4090300000041324 CVC : 387 Validity :06/2010 Affiliation : Division of Environmental Science IARI, Pusa, New Delhi 110012 State : Delhi Country : India Phone Number : +91 09899247590 E-mail: hpathak.iari@gmail.com Adresse : 18 D, Scientist Appartement Pusa, New Delhi-110012, India