Abstract: In order to explore the effects of different ombinations of nitrogen application on the soil nitrogen and yield of the winter wheat-summer soybean rotation system in 2017-2018, field experiments were carried out in the Yining County Agricultural Science and Technology Demonstration Garden, using the winter wheat-summer soybean rotation. Four nitrogen application levels were set in the previous wheat season: 0 (N0), 104 (N1), 173 (N2), 242 kg·hm^-2 (N3) and 3 nitrogen application levels were set in the subsequent soybean season: 0 (S0), 69 (S1), 138 kg·hm^-2 (S2), to study the effects of different nitrogen application combinations on the soil nitrate-nitrogen (NO₃-N), ammonium-nitrogen (NH₄⁺-N) and inorganic nitrogen residue in the 0~100 cm soil layer and yield of the farmland after crops harvest. The results showed that soil NO₃-N and NH₄⁺-N contents of winter wheat at different nitrogen levels reached the maximum in the 20~40 cm soil layer, and the soil NO₃-N and NH₄⁺-N contents of N3 reached the highest, reaching 14.65 mg·kg^-1 and 4.26 mg·kg^-1, respectively, the soil NO₃-N content were 92.86%, 44.69%, and 17.03%, respectively, higher than that of N0, N1, and N2, and the soil NH₄⁺-N increased by 69.95%, 26.10% and 8.46% in turn. The higher the nitrogen application rate in winter wheat, the greater amount of residual inorganic nitrogen in the soil, among them, N3 was the highest in the wheat season, which was 200.62 kg·hm^-2. In addition, nitrogen application in the previous wheat season could also affect the content of soil NO₃-N, NH₄⁺-N and residual inorganic nitrogen in the following soybean; the soil NO₃-N and NH₄⁺-N content of summer soybeans were also highest in the 20~40 cm soil layer, and the soil NO₃-N, NH₄⁺-N content and inorganic nitrogen residues of N3S2 were largest, the average value was 18.61 mg·kg^-1, 5.10 mg·kg^-1 and 258.36 kg·hm^-2, respectively. The winter wheat yield was the highest with 7 828.64 kg·hm^-2 under the nitrogen application of 173 kg·hm^-2 (N2), and the average yield was 35.45%, 16.77%, and 6.26% higher than that of N0, N1, and N3, respectively; On this basis, when 69 kg·hm^-2 nitrogen was applied to summer soybeans (S1), the yield of summer soybeans was the highest, with an average of 2 988.93 kg·hm^-2, and the annual total yield also reached the highest, at 10 817.5 kg·hm^-2. In summary, 173 kg·hm^-2 nitrogen application in the wheat season and 69 kg·hm^-2 nitrogen application in the bean season not only benefit to increase the annual yield of wheat and beans, but also reduce the residual nitrogen in the soil, which can provide a certain reference standard for two crops a year system with high efficient nitrogen application.

Key words: annual nitrogen application, winter wheat-summer soybean rotation system, soil nitrogen, yield

摘要： 为探讨周年不同施氮组合对冬小麦-夏大豆轮作体系土壤氮素及产量影响规律,于2017—2018年,在伊宁县农业科技示范园内开展大田试验,以冬小麦-夏大豆轮作为研究对象,在前茬麦季设置4个施氮水平:0(N0)、104(N1)、173(N2)、242 kg·hm^-2(N3);后茬大豆设置3个施氮水平:0(S0)、69(S1)、138 kg·hm^-2(S2),研究周年不同施氮组合对两季作物收获后农田0~100 cm土层土壤硝态氮(NO₃^--N)、铵态氮(NH₄⁺-N)含量、无机氮残留量及产量的影响。结果表明,冬小麦不同施氮水平土壤NO₃^--N及NH₄⁺-N含量均在20~40 cm土层达到最大值,且N3的土壤NO₃^--N和NH₄⁺-N含量最高,分别达到14.65 mg·kg^-1和4.26 mg·kg^-1,土壤NO₃^--N含量平均分别较N0、N1、N2增加了92.86%、44.69%和17.03%,土壤NH₄⁺-N平均依次增加了69.95%、26.10%和8.46%;而冬小麦施氮量越高,其土壤无机氮残留量越大,以麦季N3平均最高,为200.62 kg·hm^-2。此外,前茬麦季施氮还能影响后茬大豆土壤中NO₃^--N、NH₄⁺-N含量及无机氮残留量;夏大豆的土壤NO₃^--N和NH₄⁺-N含量也在20~40 cm土层达到最大值,且N3S2的土壤NO₃^--N、NH₄⁺-N含量及无机氮残留量最大,平均分别为18.61 mg·kg^-1、 5.10 mg·kg^-1、258.36 kg·hm^-2。在麦季施氮173 kg·hm^-2时(N2),冬小麦产量最高,平均为7 828.64 kg·hm^-2,平均分别较N0、N1、N3增加35.45%、16.77%、6.26%;且在此基础上夏大豆当季再施氮69 kg·hm^-2时(S1),夏大豆获得产量最高,平均为2 988.93 kg·hm^-2,其周年总产量也达到最高平均,为10 817.5 kg·hm^-2。综上所述,麦季施氮173 kg·hm^-2,豆季施氮69 kg·hm^-2既有利于提高麦豆周年产量,又能减少土壤氮素的残留量,可为当地一年两熟制高效施氮制度提供一定的参考标准。

关键词: 周年施氮, 冬小麦-夏大豆轮作体系, 土壤氮素, 产量