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作 者 ：尹晓芳;同延安;张树兰;曾艳娟;高鹏程;周军;杨宪龙

期 刊 ：应用生态学报 2010年 21卷 3期 页码：640-646

关键词：NO3--N淋溶；原位测定；小麦/玉米轮作；

Keywords:nitrateleaching, in-situdetermination, wheat-maizerotation,

摘 要 ：

通过田间原位淋溶装置研究了不同施氮量和秸秆覆盖对关中地区小麦/玉米轮作农田90 cm深处硝态氮（NO₃^--N）淋溶量、0～1 m土层硝态氮累积及作物产量和氮平衡的影响 q.试验设不施氮（N₁，0 kg·hm^-2·a^-1）、常规施氮（N₂，471 kg·hm^-2·a^-1）、推荐施氮（N₃，330 kg·hm^-2·a^-1）、减量施氮（N₄，165 kg·hm^-2·a^-1）、增量施氮（N₅，495 kg·hm^-2·a^-1）和推荐施氮+秸秆覆盖（N₃+S）6个不同施肥处理.结果表明：NO₃^--N淋溶量随施氮量的增加而增大，氮肥的过量施用及秸秆覆盖易造成NO₃^--N淋溶.N₃+S处理90 cm处年NO₃^--N流失量最大,为22.32 kg·hm^-2,施肥造成的氮流失量为16.44 kg·hm^-2,比相同施氮量不覆盖处理（N₃）高158.9%,NO₃^--N主要累积在20～60 cm土层,年施氮量330 kg·hm^-2（N₃）时,秸秆覆盖与否不影响NO₃^--N的剖面分布.各施肥处理对作物产量没有显著影响,但减量施氮处理（N₄）有减少作物产量的趋势.在本试验条件下,推荐施肥量(小麦施氮150 kg·hm^-2,玉米施氮180 kg·hm^-2)在保证作物产量的同时,可减少土壤NO₃^--N的淋溶和累积.

Abstract:

By using in situ leaching device, a field experiment was conducted to study the effects of nitrogen fertilization rate and straw mulching on the nitrate leaching at 90 cm soil depth, nitrate accumulation in soil profile (0-100 cm), crop yield, and nitrogen balance of wheat-corn rotation farmland in Guanzhong area of Shaanxi. Six treatments were installed, i.e., no fertilization (N₁,0 kg·hm^-2·a^-1), conventional fertilization (N₂, 471 kg·hm^-2·a^-1),recommended fertilization (N₃, 330 kg·hm^-2·a^-1), reduced N application (N₄, 165 kg·hm^-2·a^-1), increased N application (N₅, 495 kg·hm^-2·a^-1), and recommended fertilization plus straw mulching (N₃+S). The nitrate leaching loss was increased with increasing N fertilization rate. Excessive N fertilization and straw mulching could easily cause nitrate leaching. In treatment N₃+S, the annualNO₃^--N loss at 90 cm soil depth was the greatest (22.32 kg N·hm^-2), and the NO₃^--N loss from N fertilization was 16.44 kg N·hm^-2·a^-1, being 158.9% higher than that in treatment N_3. Nitrate mainly accumulated in 20-60 cm soil layer. When the N application rate was 330 kg N·hm^-2·a^-1, straw mulching had less effect on theNO₃^--N distribution in soil profile. No significant difference was observed in the crop yield among the treatments, but reduced N application (N₄) tended to decrease the yield. Under our experimental condition, a fertilization rate of 150 kg N·hm^-2·a^-1 for wheat and 180 kg N·hm^-2·a^-1 for maize could ensure the crop production and reduce the soil nitrate leaching and accumulation.

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