Soil Quality Indicators and Microbial Development in Organic and Conventionally Farmed Paddy Wetlands Ecosystem in Kerala – India

Increasing global concerns about impacts of toxic chemicals, energy crisis and environmental protection, it is becoming more important to rely on local abundant agricultural bio resources than on chemical fertilizer. Understanding the effects of organic farming on the soil quality parameters, such as microbial activity and soil nutrient content, is of central importance to concepts of sustainability. Investigation were done on the quantity, type and application of organic amendments on temporal dynamics of paddy soil organic carbon (SOC), soil total nitrogen (STN) and soil microbial biomass (SMB). The study was conducted in a paddy wetlands of Padayatti in Erumayur panchayat, Palakkad, Kerala as part of the “Agro-Biodiversity Enhancement Programme” by Kerala State Biodiversity Board, to promote organic farming in the state. The data collected on the soil chemical and microbial parameters from selected organic farming stations (St. 1-3) in comparison to chemical fertilizer applied conventional stations (St. 4) from July 2009 to October 2010 formed the basis of this paper. In the present study it was observed that soil in Padayetti under organic cultivation was able to maintain marginally increased concentration of total soil organic carbon (SOC), soil organic matter (SOM), total nitrogen (TN) and soil microbial biomass as compared to the conventional fertilizer systems. Even though considerable variation could be observed in the organic and conventional fields in the context of soil chemical and biological parameters, however they were not very much pronounced. The average soil organic carbon value ranged from 0.379 to 1.26% whereas soil total nitrogen was in the range of 0.739 to 0.85%. Study stations with organic amendments showed enriched microbial biomass and nutrient availability than fertilizer applied fields. The heterotrophic microbial count showed an average highest value of 20x 10 6 cfu/g soils in organic station, whereas was 90x10 4 cfu/g soils in fertilizer applied station. Therefore this study recommends long term application of organic inputs for restoring the native soil properties and health.