1.Huazhong Agricultural University and Jiangxi Institute of Soil and Water Conservation;2.Huazhong Agricultural University;3.Jiangxi Institute of Soil and Water Conservation
National Natural Science Foundation of China (No. 41761060 and 42067020), the Provincial Key Research and Development Program of Jiangxi (No.20192BBF60058) and the Science Foundation of Jiangxi Provincial Water Conservancy Department (No. 201821ZDKT20)
【目的】针对红壤旱坡地土壤侵蚀严重和渗漏淋溶强烈并存的现状，为探讨减量施氮对作物产量、氮素径流和渗漏损失特征及氮素表观平衡的影响，【方法】选择赣北红壤旱坡花生地开展田间随机区组试验，设置5个处理：100%施氮量（N100%，纯施氮180 kg·hm-2）、减1/6施氮量（N1/6）、减1/3施氮量（N1/3）、减1/2施氮量（N1/2）和不施氮（N0），每个处理重复3次。【结果】结果表明：（1）与N100%处理相比，N1/6和N1/2处理的花生产量和植株吸氮量略低，但差异不显著（P>0.05）；与N100%处理相比，N1/6和N1/2处理在主茎长、株高、冠幅、饱果数和原始分枝数等农艺性状上无显著性差异（P>0.05）。（2）与N100%处理相比，N1/6、N1/3、N1/2、N0处理显著（P<0.05）降低了地表径流TN平均浓度，降幅分别为14.36%、26.35%、14.01%、21.34%；与N100%处理相比，N1/3、N1/2和N0处理降低了渗漏TN平均浓度，而N1/6处理提高了渗漏TN平均浓度。（3）有34.95~93.98 kg·hm-2氮素流出该花生种植体系，其中径流流失和渗漏淋失的氮量占38.31%~70.50%，高于气体等其他表观损失的氮量（29.50%~60.63%）。【讨论】这表明径流流失和渗漏淋失是红壤旱坡花生地氮素损失的重要途径。（4）在新开垦土地上不施氮处理降低了土壤无机氮量而减氮施肥处理增加了土壤无机氮量，增加幅度达18.66%~31.44%，减氮施肥可以提高土壤肥力。综合生产目标、环境影响及土壤肥力来看，红壤旱坡花生地推荐施氮水平为90 kg·hm-2。
【Objective】Severe soil erosion and water leakage on dry slopes of red soils are a common phenomenon that results in significant nitrogen loss. These occurrences cause nitrogen imbalance and subsequent yield losses. This study aimed to explore the effects of different levels of reduced nitrogen fertilization on crop yield and nitrogen loss characteristics. 【Method】Randomized field trials comprising of five nitrogen treatments in three replicates were set up in peanut fields located in the dry slopes of northern Jiangxi characterized by red soils. The five treatments were 100% nitrogen application rate (N100%, pure nitrogen application of 180 kg·hm-2), 1/6 (N1/6), 1/3 (N1/3), 1/2 (N1/2), and zero (N0) nitrogen application rates. 【Result】The peanut yield and plant nitrogen uptake of N1/2 and N1/6 treatments were insignificantly lower than those of the N100% treatment (P>0.05). Besides, N1/6 and N1/2 treatments had no significant differences in agronomic characteristics such as the main stem length, plant height, crown width, number of full fruits, and the number of original branches (P>0.05). N1/6, N1/3, N1/2, and N0 treatments significantly reduced the average total nitrogen (TN) concentration in the surface runoff by 14.36%, 26.35%, 14.01%, and 21.34%, respectively, compared to the N100% treatment (P<0.05). Also, N1/3, , N1/2,, and N0 treatments reduced the average TN concentration in the leakage compared to the N100% treatment. However, the average increase in TN leakage concentration in the N1/6 treatment was not significantly different from that of the N100% treatment (P>0.05). The nitrogen output from the peanut planting system ranged between 34.95 and 93.98kg·hm-2. Nitrogen losses from runoff and leakage ranged between 38.31% and 70.50%, while other apparent nitrogen losses such as gaseous losses ranged between 29.50% and 60.63%. 【Conclusion】This finding affirmed the significance ofin nitrogen loss through runoff and leakage. Non-nitrogen treatment on newly reclaimed land reduced the soil inorganic nitrogen while reduced-nitrogen fertilization increased the soil inorganic nitrogen by up to 31.44%. Thus, rReduced nitrogen fertilization could, therefore, maintain a constant soil fertility level. Based on the comprehensive production goals, environmental impacts, and soil fertility, 90 kg·hm-2 is the recommended nitrogen application rate for peanuts planted in dry slope land with red soils.
Zheng Wenqi, Tan Wenfeng, Liu Zhao, Wang Lingyun, Zheng Haijin. Effect of Reduced Nitrogen Fertilization on Nitrogen Runoff Loss and Apparent Balance on Red-soil Dry Slope Peanut Land[J]. Acta Pedologica Sinica,,[In Press]