Jilin Agricultural University
the National Natural Science Foundation of China (U19A2035，41907081) and the Natural Science Foundation of Jilin Province（20200201017JC）
探究不同秸秆还田方式下肥料氮在连续两季作物系统中的去向，为黑土地保护下的氮肥管理提供重要依据。于2020-2021年在吉林梨树开展大田微区试验，设置无秸秆还田 (CK)、深翻还田 (DTS)、免耕覆盖还田 (NTS) 3种秸秆还田方式，每种方式下设置2个施氮水平：180 kg·hm-2(N1)和270 kg·hm-2(N2)。结果表明：当季和第二季玉米成熟期植株氮分别有38.0%-46.8%和12.9%-18.6%来源于15N标记氮肥。肥料氮当季平均利用、残留和损失率分别为32.4%-43.9%，32.8%-51.4%和13.2%-32.7%，秸秆覆盖配施适量氮肥 (180 kg·hm-2) 显著提高肥料氮当季利用率29.5%，而秸秆深翻还田则显著增加肥料氮在土壤中的残留率18.2%。当季施用肥料氮仍有8.5%-14.9%被第二季玉米吸收利用，两季累积利用率达40.9%-58.8%，在高氮（270 kg·hm-2）下秸秆深翻还田显著提高肥料氮在第二季及累积利用效率。综上，秸秆覆盖还田配施适量氮肥有利于提高肥料利用效率，而秸秆深翻还田更有利于高施氮量下土壤对肥料氮的保持，增加其被下季作物利用的机会，两者均能显著减少氮的损失。
【Objective】Investigating the fate of fertilizer nitrogen in a two-season crop system under different straw returning methods can provide an important basis for nitrogen management under black soil protection.【 Method】This study conducted a 15N micro-plot experiment in 2020-2021 at Lishu County of Jilin Province using the 15N tracer technique. Three straw-returning methods were set up: no straw returning (CK), straw deep tillage returning (DTS) and straw mulching with no tillage (NTS). Under each method, two nitrogen levels were set: 180 kg·hm-2 (N1) and 270 kg·hm-2 (N2). 【Result】At maturity stage, 38.0-46.8% and 12.9-18.6% of plant nitrogen in the current season and the second season were derived from 15N labeled nitrogen fertilizer, respectively, and fertilizer nitrogen was mainly distributed in grains (59.8-68.5% in the current season and 59.3-79.6% in the second season). The utilization, residual and loss rates of fertilizer nitrogen in the current season were 32.4-43.9%, 32.8-51.4% and 13.2-32.7%, respectively. The NTS combined with an appropriate amount of nitrogen fertilizer (180 kg·hm-2) significantly increased the utilization rate of fertilizer nitrogen by 29.5%, while DTS significantly increased the residual rate of fertilizer nitrogen in soil by 18.2%. Also, the utilization and loss rates of fertilizer nitrogen in the second season were 8.5-14.9% and 5.1-14.6%, respectively. The cumulative utilization, residual and loss rates were 40.9-58.8%,10.4-26.4% and 18.4-47.3%, respectively. Compared with CK, NTS treatment significantly increased fertilizer nitrogen utilization efficiency by 18.3% (N1) and 45.9% (N2) in the second season, while the DTS treatment significantly increased fertilizer nitrogen utilization efficiency in the second season by 42.3% under N2. For the total fate of fertilizer nitrogen in two crops, compared with CK, NTS treatment significantly increased the cumulative utilization efficiency of fertilizer nitrogen by 26.4% (N1) and 21.8% (N2), while DTS treatment significantly increased the total residual rate of fertilizer nitrogen by 64.0% (N1) and 72.9% (N2). In addition, the NTS and DTS treatments significantly reduced the total losses of fertilizer nitrogen. Compared with N2, the N1 treatment significantly increased the utilization and residual rates of fertilizer nitrogen and reduced the loss rate of fertilizer nitrogen in two seasons. 【Conclusion】Straw mulching combined with an appropriate amount of nitrogen fertilizer is beneficial to improve fertilizer use efficiency while straw deep plowing is more conducive for the maintenance of fertilizer nitrogen in the soil, especially under high nitrogen application rate, and increases the use efficiency by next crop. Both straw mulching and straw deep plowing could significantly reduce nitrogen loss.
wumengna, Wang Shaojie, Lan Chang, Yan Xu, Feng Guozhong, Gao Qiang. The Fate of Fertilizer Nitrogen under Different Straw Returning Methods in Maize Field of Black Soil[J]. Acta Pedologica Sinica,,[In Press]