Promoted decomposition in straw return to double-cropped rice fields controls soil acidity, increases soil fertility and improves rice yield

Abstract

Rice straw returned directly to the field offers various benefits, including improved soil structure, water conservation, and crop growth. However, straw decomposition can create unfavorable conditions, such as soil acidification and gleyization, that negatively impact rice growth. This study conducted three experiments to assess the effects of returning straw to double-cropping rice fields by screening for decomposing bacteria, nutrient release, and complete straw return. The results from these experiments indicated that the decomposition efficiency of straw significantly increased when both pig manure and straw were returned to the field simultaneously. Additionally, the introduction of exogenous calcium oxide increased the soil pH by more than 0.3, effectively preventing soil acidification. Furthermore, after four years of continuous straw return, the addition of calcium oxide or pig manure significantly increased the annual rice yield. These findings provide scientific evidence supporting the long-term advantages of incorporating straw return into the soil fertilization practices of double-cropping rice systems, highlighting the potential for sustained improvement in soil fertility.