Effects of Different Controlled-Release Fertilizers on Wheat-Maize Yield, N Balance and N Loss in Huang-Huai-Hai Region of China

Abstract

The appropriate controlled-release fertilizers (CRFs) vary based on different regions and crops. Screening suitable CRF can match the release of nutrients with crop demand according to climate characteristics and nutrient absorption rates, improving fertilizer utilization efficiency. An experiment with wheat-maize rotation was conducted in 2016 and 2017, with treatments including the typical farmer practice (FP), CRFA, CRFB, CRFC, and CRFD treatments. The effects of different CRFs on crop yield, soil inorganic nitrogen (N) content, and N balance were studied, and N surplus was used to evaluate the use effect of N fertilizers. The results showed that CRFA and CRFB maintained the yields of wheat and maize under N reduced by 14.3% and 11.8%, respectively, compared with FP. The yields of wheat in 2016 and maize in 2017 in the CRFB treatment were significantly higher than in the CRFC treatment. There were no significant differences between the remaining treatments. There had higher soil inorganic N content of upper soil, lower content of deeper soil in the CRFA and CRFB treatments, and significantly lower than in the FP treatment in the 60 cm-80 cm soil at harvest. In CRFC, there was a higher residual inorganic N in the entire soil profile as well as in the 60 cm-100 cm layer for CRFD. The results of the N balance analysis in the soil-crop system showed that N uptake was the greatest, N loss was relatively lower for CRFA in 2016. N uptake for CRFB in 2017 was remarkably higher than that of CRFC and CRFD, and N surplus and N loss were both the lowest. There was no remarkable difference in N uptake between FP and other treatments. Under the same N input, N uptake had a negative relationship with N surplus. There was no apparent relationship for N loss and N surplus in 2016. However, in 2017, N loss increased with the increase of N surplus, and there was no remarkable difference for soil total N among treatments during the two years of experiments. In this region, CRFA and CRFB are better able to maintain a stable crop yield, reducing N loss and maintaining N balance. This is an excellent choice for adapting to local soil climatic conditions.