Organic soil amendments using vermicomposts under inoculation of N-fixing bacteria for sustainable rice production.

Organic and biological fertilizers are considered as a very important source of plant nutrients. A field experiment was conducted during 2017-2018 in paddy soil to investigate the effect of vermicomposting of cattle manure mixture with and rice straw on soil microbial activity, nutrient uptake, and grain yield under inoculation of N-fixing bacteria. Experimental factors consisted of organic amendments at six levels (vermicomposts prepared from manure (VM); manure + rice straw (VRM); manure + mixture (VAM); manure + rice straw + mixture (VRAM); raw manure without vermicomposting (M), and a control) and N-fixing bacteria at three levels (, , and non-inoculation). The results showed that, vermicompost treatments compared to control and raw manure significantly increased the number and biomass-C of soil microorganisms, urease activity, number of tillers hill, phosphorus (P) and potassium (K) uptake, and grain and protein yield. Inoculation of plants with N-fixing bacteria, especially increased the efficiency of organic amendments, so that the maximum urease activity, soil microbial activity, P and N uptake, and grain yield (4,667 (2017) and 5,081 (2018) kg/h) were observed in vermicompost treatments containing (VAM and VRAM) under inoculation with . The results of the study suggested that, using an organic source along with inoculation with appropriate N-fixing bacteria for vermicompost has a great effect on enzyme activity, soil biology, nutrient uptake and grain yield has a synergistic interaction on agronomic traits under flooded conditions. Therefore, this nutrient method can be used as one of the nutrient management strategies in the sustainable rice production.