CROP PRODUCTIVITY AND SOIL HEALTH IN RELATION TO MICROBIAL ACTIVITIES IN SCENTED ORGANIC RICE SYSTEM
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Date
2017
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Indira Gandhi Krishi Vishwavidhyalaya, Raipur
Abstract
A field study was conducted during Kharif, 2016 in Instructional cum Research farm, IGKV, Raipur, in an Inceptisols with rainy season rice to evaluate the effect of different combinations of organic manures along with biofertilizers on physico-chemical, chemical, microbial, biochemical properties of soil and crop yield. Different chemical and non –chemical weed management techniques were also evaluated to find out the suitability.Three different types of organic manures i.e. FYM, Poultry manure and Vermicompost were mixed in different combinations . Nitrogenous and phosphatic biofertilizeres i.e. Azospirillum and PSB were also applied through seed inoculation uniformly to all the organic manure treatments. The combinations of organic manures have done in such a way so that the crop N demand has been fulfilled. Three treatmens (i) FYM (50% N) +Vermicompost (50% N) + Azospirillum + PSB , (ii) FYM (50% N) + Poultry Manure (50%N) +Azospirillum + PSB and (iii) FYM (50% N) + Vermicompost (25% N) + Poultry Manure (25% N) +Azospirillum + PSB put in main plots. Different weed control practices have also been evaluated to find out their suitability for organic farming of rice , compared with weedy check. These weed control practices are hand weeding, motorized weeding and recommended herbicides application (oxadiargyl 80 g/ha as pre emergence and fb bispyribac 25 g/ha as post emergence) which were put in sub plots.
The results of the investigation revealed that the 50% nitrogen management through FYM , 50% nitrogen management by poultry manures and application of biofertilizers Azospirillum and PSB was found most effective to improve the physico-chemical, chemical, biochemical microbial properties of soil and crop yield. Under this system the pH of the soil tended towards normality . Soil organic carbon was also found at maximum level due to above combination of organic manures. Maximum microbial activity like Dehydrogenase activity, Acid phosphatase activity, Basal soil respiration were found under this nutrient management system. Higher microbial biomass carbon content and microbial population were also recorded in this system. Among different weed control systems application of recommended herbicides found most effective to increase the rice yield significantly. However, among non-chemical weed, management methods motorized weeding was found comparatively better over hand weeding but both found at par.
Application of pre emergence and post emergence herbicide reduced the microbial and biochemical activities in soil from its application (6 and 29 days after sowing, respectively) to 30 days after sowing of the crop thereafter due to its degradation the microbial and biochemical activities in the soil system improved and reached to a maximum at 50 DAS. At harvest stage of the crop the levels of the above parameters were found statistically similar to that of hand weeded and motorized weeded conditions which indicated that applied herbicides at recommended level did not leave any harmful residues in soil system at harvest stage of the crop. Control (Weedy check) condition facilitated more microbial and biochemical activities in rhizosphere soil which might be due to higher root density per unit area caused greater rhizosphere effect.
Description
CROP PRODUCTIVITY AND SOIL HEALTH IN RELATION TO MICROBIAL ACTIVITIES IN SCENTED ORGANIC RICE SYSTEM
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