Sustainable strategies related to soil fertility, economic benefit, and environmental impact on pear orchards at the farmer scale in the Yangtze River Basin, China.

Pears are an important income source in China, and unreasonable management practices have had a negative impact on the sustainability of pear orchards. However, multi-objective synergistic strategies are unclear on a farmer scale. In this study, we quantified indicators of soil fertility (soil organic matter (SOM)), environmental impact (global warming potentials (GWP)), and economic benefit (ratio of benefit and cost (BCR)) and analysed the synergetic strategies based on survey data from 230 smallholders in the Yangtze River Basin (Shanghai City, Chongqing City, Zhejiang province, and Jiangxi province). The average SOM, GWP, and BCR were 28.9 g kg-1, 17.3 t CO2-eq ha-1, and 3.63, respectively. Furthermore, optimised solutions using the Pareto multiple-objective optimisation model can reduce the GWP by 44.6% and improve the SOM and BCR by 34.4% and 43.9%, respectively, when fertiliser N rate and density are both decreased and the ratio of organic fertiliser application is increased compared to farmer management practices. The structural equation model indicated that planting density and fertiliser N rate can directly influence GWP and indirectly increase SOM and BCR; organic fertiliser application directly affects the GWP, SOM, and BCR. Our research provides a bottom-up approach based on the farmer scale, which can improve the sustainability of pear systems, and these findings can be used as guidelines for policymakers and pear orchard managers.

Wheat yield and nitrogen use efficiency enhancement through poly(aspartic acid)-coated urea in clay loam soil based on a 5-year field trial.

The innovation of N fertilizer and N management practices is essential to maximize crop yield with fewer N inputs. A long-term field fertilization experiment was established in 2015 on the North China Plain (NCP) to determine the effects of a control treatment (CN) and the eco-friendly material poly(aspartic acid)-coated urea (PN), applied as a one-time basal application method, on winter wheat yield and N use efficiency at four N application rates: 0 (N0), 63 (N63), 125 (N125), and 188 (N188) kg N ha-1. The results indicated that compared to CN, PN resulted in a significant increase in wheat yield by 9.6% and 9.2% at N63 and N125, respectively, across the three experimental years, whereas no significant (p < 0.05) difference was detected at N188. Leaf area duration (LAD), crop growth rate (CGR), and dry matter accumulation (DMA) increased with increasing N rates, while PN significantly increased LAD and CGR by 5.1%-16.4% and 5.4%-64.3%, respectively, during the anthesis-ripening growth stage and DMA by 13.7% and 10.1% at N63 and N125, respectively, after the anthesis stage compared to CN. During the grain-filling stage, PN significantly increased the kernel maximum grain-filling rate (Gmax) by 21.7% and the kernel weight at the maximum grain-filling rate (Wmax) by 6.7% at N125 compared to CN. Additionally, compared to CN, PN significantly improved the stover and grain N content at harvest and increased NUT, NPFP, and NAE by 5.7%-40.1%, 2.5%-23.3%, and 3.9%-42.8%, respectively, at N63-N125. Therefore, PN applied using a single basal nitrogen fertilizer application method showed promising potential in maintaining a stable wheat yield and increasing N use efficiency with a 33% urea cut (approximately 63 kg N ha-1) compared to CN at the current wheat yield level on the NCP.

Effects of basic application of chlorocholine chloride combined with nitrogen fertilizer on nitrogen use of summer maize in North China Plain.

To clarify the effects of combined applications of chlorocholine chloride (CCC) and nitrogen fertilizer (CN) on nitrogen metabolism and nitrogen use efficiency of summer maize, we conducted a field experiment in Xinxiang experimental station of Chinese Academy of Agricultural Sciences in 2018 and 2019, with four nitrogen application rates (0, 62.5, 125 and 187.5 kg·hm-2), and two maize varieties of Jingnongke 728 (JNK728) and Zhongdan 909 (ZD909). The results showed that across the two years CN-CCC increased maize yield by 7.7% and 5.0% under the nitrogen application rates of 62.5 kg·hm-2 and 125 kg·hm-2, respectively. CN-CCC increased the contents of nitrate reductase, glutamine synthetase, glutamate synthetase and soluble protein, and finally promoted nitrogen metabolism. Under the low and middle nitrogen application conditions (62.5 kg·hm-2 and 125 kg·hm-2), plant nitrogen content of JNK728 and ZD909 increased by 17.6% and 30.3%, grain nitrogen content increased by 10.3% and 17.4%, nitrogen partial productivity, agronomic efficiency of applied nitrogen, recovery efficiency of applied nitrogen, nitrogen use efficiency increased by 10.0%, 15.7%, 23.3%, 24.8% and 5.7%, 15.0%, 49.9%, 71.7%, respectively. In conclusion, appropriate basic application of CN-CCC could enhance nitrogen metabolism, increase nitrogen use efficiency and grain yield of summer maize. Our results showed that CCC combined basic nitrogen application of 125 kg·hm-2 had the best effect.