Increasing yield and nitrogen use efficiency of spring maize in Northeast China through ecological intensification management

Objectives In view of the problems in ecological environment and sustainable agricultural development caused by excessive and unreasonable fertilizer application in spring maize production in China, the effects of ecological intensive nutrient management on spring maize yield, nitrogen use efficiency and nitrogen balance in Northeast China were studied in order to make full use of resources, increase production efficiency and ensure national food security scientifically and rationally.

Methods A long-term experiment was conducted from 2009 to 2017 in Gongzhuling City, Jilin Province. Two factors of split plot were designed in the experiment. The main plot was two fertilization managements: the ecological intensive nutrient management (EI) and farmer practice management (FP). The sub-plot was three N application methods, including no N application treatment (N0), N application in two of three years (N2/3) and in three years (N3/3). In EI treatment, P₂O₅ 75 kg/hm², K₂O 90 kg/hm², S 30 kg/hm², Zn 5 kg/hm² and 1/4 of N (180 kg/hm² in 2009–2014, 200 kg/hm² in 2015–2017) applied as basal, 1/2 N top dressed at jointing stage and 1/4 N at tassel stage. In the treatment of FP, N 251 kg/hm², P₂O₅ 145 kg/hm² and K₂O 100 kg/hm² were applied once as basal. The yield, N uptake and accumulation of maize and the balance of soil N were investigated.

Results In N0 treatment, the yield and N uptake showed a downward trend since 2010. In N2/3 treatment, the yield and N uptake decreased in the year without N application, and increased to the level of N3/3 treatment in the case of N application in the following year. In EI treatment, the average yield of N3/3 treatment was 11505 kg/hm² in 9 years, while that of FP treatment was significantly lower, which was 10764 kg/hm². Compared with FP treatment, EI treatment significantly increased nitrogen agronomic efficiency (AE_N), recovery efficiency (RE_N) and partial factor productivity (PFP_N) by 47.4%, 39.6% and 43.8%, respectively. The residual N and apparent loss of N in EI treatment were 49.2% and 63.9% lower than those in FP treatment, respectively.

Conclusions Ecological intensive nutrient management, including right fertilization rate and time, and suitable cultivar and plant density, is proved to be effective in increasing spring maize yield and N utilization, reducing residue and apparent loss of N in soil. The experiment also confirms that continuous appropriate N fertilizer application is essential for high and stable yield of maize in Northeast China.