Plow tillage with straw return improved corn yield by regulating canopy light interception and N distribution

Abstract

Abstract Straw return offers an effective way to achieve soil sustainability. However, there is a limited amount of research addressing the impact of nitrogen application and straw return method on the vertical distribution of crop canopy and nitrogen allocation. The experiment was based on a long-term field experiment that started in 2011 and was conducted at the Halahai Comprehensive Experimental Station in Nong'an County, Jilin Province. Sampling was carried out in 2021 and 2022 to analyse the canopy distribution and nitrogen allocation of the maize hybrid Fumin 985 under two straw returning methods, no tillage with straw mulch (SM) and plow tillage with straw return (SP), and five nitrogen application rates: 0 (N0), 90 (N90), 150 (N150), 210 (N210), and 270 kg N ha− 1 (N270). The present study indicated that under a nitrogen application rate below N150, the yield was on average 11.66% − 24.34% higher in SP than in SM. This difference was mainly attributed to the variation in 1000-grain weight. Furthermore, SP maintained a higher leaf area index (LAI) and total radiation interception rate (RIR) during the grain filling stage with the same nitrogen application rate compared to SM. It also significantly increased post–flowering dry matter accumulation by 8.87% − 69.26% compared to SM. Additionally, SP significantly improved the proportion of grain dry weight and led to an increase of 10.35% − 16.04% in 1000-grain weight compared to SM. Moreover, SM increased the relative nitrogen content in grain, which in turn improved nitrogen uptake efficiency (NUpE) and grain nitrogen use efficiency (NUE). Finally, SP demonstrated a synergistic enhancement in yield and NUE under lower nitrogen application rates than SM. In summary, the combination of SP with nitrogen fertilizer application proves to be an effective method to achieve high yield and high efficiency maize production compared to SM.