Increasing grain yield, nitrogen use efficiency of summer maize and reducing greenhouse gas emissions by applying urea ammonium nitrate solution

Abstract

The contradiction between the high grain yield of summer maize (Zea mays L.) and greenhouse gas (GHG) emissions in the field can be resolved by selecting effective nitrogen (N) sources and fertilization methods. In this study, two fertilization methods were used: (a) urea ammonium nitrate solution (UAN) and urea (210 kg ha–1 nitrogen applied) were applied by farmers' traditional fertilization method; and (b) fertigation of four UAN application rates: CK (no N applied), AF1 (126 kg N ha–1), AF2 (168 kg N ha–1), AF3 (210 kg N ha–1). The results showed that both hybrids (DH518 and DH605) applied UAN under the traditional fertilization method increased grain yield by 2.4 and 1.8% and enhanced nitrogen use efficiency (NUE) by 25.1 and 9.9%, respectively, compared with urea. While under fertigation treatment, the grain yield increased by 7.6 and 6.6%, and the NUE increased by 23.2 and 12.4%. Grain yield increased with the increase of UAN application, and the NUE showed a trend of rising first and then falling under fertigation treatment. Both the cumulative N2O emissions and N2O emission factor showed an increasing trend as well. An application rate of UAN at 168 kg N ha–1 (AF2) resulted in a NUE that was 49% higher than urea. Compared with urea, the global warming potential (GWP) and greenhouse gas intensity (GHGI) of AF2 were reduced by 29.5% and 31.2%, respectively. These indicated that optimizing the application rate of UAN through fertigation would achieve better summer maize yield and environmental benefits.

Yield of summer maize hybrids with different growth duration determined by light and temperature resource use efficiency from silking to physiological maturity stage

“…DH605 is one of the most popular maize hybrids in China at present, and DH518 is a newly released hybrid that is being promoted. DH605 (mid-late hybrid) and DH518 (mid-early hybrid) have different growth duration, which are widely representative ( Ma et al., 2022 ). Therefore, we analyzed the yield, accumulated temperature demand characteristics, leaf photosynthetic characteristics, and DMA and distribution characteristics of different summer maize hybrids to explore the effects of the changes in the growth duration on DMA and distribution and yield.…”