|Title||Estimation of nitrogen supply for winter wheat production through a long-term field trial in China|
|Author(s)||Huang, Shaohui; Ding, Wencheng; Yang, Junfang; Zhang, Jiajia; Ullah, Sami; Xu, Xinpeng; Liu, Yingxia; Yang, Yunma; Liu, Mengchao; He, Ping; Jia, Liangliang|
|Source||Journal of Environmental Management 270 (2020). - ISSN 0301-4797|
|Publication type||Refereed Article in a scientific journal|
|Keyword(s)||Nitrogen use efficiency - Relative yield - Total nitrogen supply - Winter wheat|
Excessive synthetic nitrogen (N) applications, high mineral N accumulation and low N use efficiency (NUE) are current issues in intensively cultivated winter wheat production system impeding the sustainable development of agriculture in China. To solve these problems, soil accumulated N in the top 1 m of the soil profile before sowing (Nsoil), returned straw-N from the previous maize crop (Nstraw) and fertilizer N application (Nfertilizer) should be comprehensively considered N supply sources in N management. As such, the objective of this research was to determine the optimal total N supply (TNsupply) level needed to meet crop requirements while minimizing environmental impacts. A 9-year on-farm experiment was conducted in accordance with a split-plot design involving two different fertilizer management systems (main treatments) and three N application strategies (sub treatments). Extensive TNsupply levels (ranging from 61 kg ha−1 to 813 kg ha−1) were detected, and relative yield (RY), N input and N output in response to the TNsupply were measured. The relationships between TNsupply and RY, N input, and N output strongly fit linear-plateau, linear, and linear-plateau models, respectively. The minimum TNsupply levels needed to achieve the maximum RY and N output were 325 and 392 kg ha−1, respectively. On the basis of N supply capacity, the TNsupply was removed from the growing system by 61% (N input). As the N input increased past 209 kg ha−1, the NUE declined, at which point the TNsupply reached 433 kg ha−1. Therefore, the suitable TNsupply should range from 325 kg ha−1 (ensuring a total N supply for high yield and N uptake) to 433 kg ha−1 (obtaining a relatively higher NUE and less N loss to the environment). The TNsupply was highlighted to be an indicator for use in N management recommendations. Considering the average high N accumulation in winter wheat production systems, N management should essentially take into account the consumption of Nsoil, the levels of Nstraw and the minimum application of Nfertilizer to obtain high yields while minimizing environmental impacts under suitable TNsupply levels.