Influence of Partial Substitution of Chemical Fertilizer Through Organic Manure on Cotton Yield and Soil Fertility in Yangtze River Regions of China

Worldwide organic amendments have received much attention to improve soil fertility and crop productivity. Partial substitution of inorganic fertilizer through organic manure is a promising approach to decrease chemical fertilizer input while stabilizing or increasing crop yield. Field experiments were conducted in Hubei and Hunan provinces to assess the impact of partial substitution of chemical fertilizer through organic manure on cotton yield and soil properties during 2016 and 2017. The experimental plots (50 m2) were arranged in a randomized block design, with six treatments, and three replicates for each treatment. Our results revealed that the yield of 100% chemical fertilizer treatments was significantly higher than no fertilizer treatment in 2016, and the yield of organic fertilizer substitution treatments was higher than 100% chemical fertilizer and no fertilizer in 2017 in Hubei province. In Hunan province, the yield of replacing part of chemical fertilizer with organic fertilizer and 100% chemical fertilizer treatment was higher than those of 100% organic fertilizer and no fertilizer treatment over 2 years. Application of 100% organic fertilizer was found to be more beneficial in terms of improving soil fertility in Hubei provinces during both years. The substitution of chemical fertilizer by 50% organic fertilizer was effective to improve soil fertility and exerted a significant effect on soil available phosphorus, potassium in Hunan provinces during both years. Collectively, these results indicate that replace 100% chemical fertilizer through organic fertilizer in Hubei province and substitution of 50% chemical fertilizer in Hunan province could increase the cotton yield, improve soil fertility and reduce inorganic fertilizers, which have a potential impact on sustainable production of cotton.