Innovative fertilizer management system maintains higher maize productivity with lower environmental costs in the Loess Plateau region of China

Abstract

ContextInnovative fertilizer management is the most effective strategy for increasing crop yields and reducing environmental pollution. ObjectivesDeep fertilization reduces NH3 emissions and increases crop yield, but its effects on N2O emissions are still unclear. Nitrification or urease inhibitors trigger cross-contamination of N2O and NH3. Little is known about whether innovative fertilizer management strategies can reduce nitrogen emissions while maintaining higher yields. MethodsWe conducted field experiments using maize in the semi-humid and drought-prone areas of the Loess Plateau in China from 2019 to 2021. To further verify the research results, experiments were conducted in semi-arid and drought-prone areas in 2022 and 2023 using surface fertilization (SF), surface fertilization with nitrification (SNI) or urease inhibitor (SUI), deep fertilization (DF), and deep fertilization with urease and nitrification inhibitor (DUN) as experimental treatments. ResultsThe trends were similar at the three experimental locations over five years, where the ability of DF to reduce emissions was equivalent to those of SNI for N2O and SUI for NH3. However, the increase in the crop productivity was significantly higher under DF than SUI and SNI. Compared with SF, DF significantly reduced the N2O and NH3 emissions by 39.85 % and 46.08 %, respectively, and significantly the increased maize yield, N uptake, and nitrogen use efficiency (NUE) by 16.86 %, 15.83 %, and 32.79 %. The innovative fertilizer management strategies combined the advantages of inhibitors and deep fertilization, and they obtained the highest maize yield and NUE, as well as the lowest N2O and NH3 emissions and gaseous nitrogen loss intensity (GNLI) among all treatments. Compared with SF, DUN reduced the urease, nitrate reductase, nitrite reductase, and hydroxylamine reductase activities by 22.03 %, 58.81 %, 52.72 %, and 50.27 %, respectively, the soil NO3–-N and NH4+-N contents by 82.94 % and 53.71 %, and N2O and NH3 emissions by 80.79 %, and 79.33 %. DUN increased the maize yield and NUE by 23.30 % and 46.91 %, respectively, and decreased the GNLI by 84.69 %. ConclusionsDUN reduced the concentration of substrates for producing gaseous nitrogen by regulating the activities of soil nitrogen circulating enzymes to significantly reduce the nitrogen loss, and it achieved the highest maize yield (11,818.10 kg ha–1) and NUE (46.62 %) with the lowest GNLI (0.71 g N kg–1 grain). Innovative fertilizer management strategies can help to balance economic and environmental benefits in the Loess Plateau region of China. ImplicationsOur findings provide a reference for obtaining higher maize productivity with low environmental pollution in the Loess Plateau region of China.