Effect of application of vermicompost on methane emission and grain yield of Chinna Ponni paddy crop

Abstract

In separate treatments rice (Oryza sativa) of the Chinna Ponni variety was grown either with the application of synthetic fertilizer (SF) containing 120 kg/ha, 60 kg/ha, and 60 kg/ha of nitrogen, phosphorous, and potassium, respectively, or vermicompost (4 t/ha) with equivalent nitrogen content. The objective was to see whether vermicompost performs as well, or better, than the SF in terms of grain length, unit mass, and overall yield of rice. The relative contribution of the two fertilizer applications on the emission of the global warming gas methane was also studied. Direct sowing method was applied for the rice cultivation which spanned 140 days during which intermittent flooding of the plots was done. The average grain yield (2300 kg/ha), grain weight (21 mg), and grain length (6.3 mm) of the vermicompost-fertilized rice were all marginally higher than the corresponding values: 2060 kg/ha, 18 mg, and 6.1 mm, respectively, of the SF-fertilized rice. The overall hourly methane flux in vermicompost-fertilized plots was 111.3 ± 58.3 µg/m2 h in comparison with 71.0 ± 81.0 µg/m2 h emitted by the SF-fertilized plots, but the difference was not statistically significant.