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作 者 ：吴中伟,樊高琼,王秀芳,郑亭,陈溢,李金刚,郭翔

期 刊 ：植物营养与肥料学报 2014年 20卷 6期 页码：1338-1348

关键词：带状种植小麦；施氮量；施氮方式；产量；氮素利用效率；氮残留；

Keywords:strip-relay-intercropping wheat, nitrogen level, nitrogen application pattern, grain yield, N use efficiency, nitrogen residues in the soil,

摘 要 ：【目的】带状种植是四川小麦的典型种植方式,主要分布在丘陵旱地,与玉米构成“小麦/玉米”复合种植系统。本文通过两年大田试验研究了不同氮肥用量和生育期分配比例对四川丘陵旱地带状种植小麦氮素吸收累积、 分配与转运的影响,以及氮素利用效率和土壤氮残留问题,筛选适合于该地区带状种植小麦的适宜氮肥用量和分配比例,为生产应用提供理论和技术依据。【方法】试验在四川省仁寿县进行,试验材料为四川主推品种川麦42,带状种植(即2 m为一带,种5行小麦,行距20 cm,小麦幅宽80 cm,预留行1.2 m),2BSF-4-5A型谷物播种机播种,密度150×10⁴ plant/hm²。试验采用二因素裂区设计,施氮量为主区,设N 90(N1)、 135(N2)、 180(N3)、 225(N4) kg/hm² 4个水平;生育期分配比例为裂区,设基肥一次性施入(R1)、 底肥:苗肥=7:3(R2)、 底肥:拔节肥=7:3(R3)和底肥:苗肥:拔节肥:孕穗肥=5:1:2:2(R4)4个水平,并以不施肥(CK)为对照。【结果】 1)施用氮肥后收获期地上部植株总吸氮量显著提高,开花期植株各营养器官氮素积累量、 成熟期叶和茎鞘中氮素残留量以及转运氮的贡献率均随施氮量的增加而增加,而花后氮素同化量及其对籽粒氮的贡献率随施氮量增加呈先增后降的趋势,在施氮量为N 135 kg/hm²时达最大。底肥:拔节肥=7:3的施氮方式有利于提高花后氮素同化量及其对籽粒氮贡献率,而底肥:苗肥:拔节肥:孕穗肥=5:1:2:2的施氮方式有效地促进了花前贮存氮素向籽粒转移,同时也增加了成熟期氮素在营养器官中的残留,降低了氮素在籽粒中的分配比例;2)氮利用效率和植株氮生产力均随施氮量的增加而降低,土壤中残留的全氮、 NO^-₃-N及NH⁺₄-N含量则随施氮量的增加而增加;在施氮量较高(N 180～225 kg/hm²)的条件下,底肥一次施极大地增加了土壤中氮的残留,且随施氮量增加,拔节期一次性追肥土壤中氮残留也增加,氮肥分次追施和加大分配比例能够有效降低土壤中的氮素残留; 3)在四川丘陵旱地套作条件下,施氮量和籽粒产量的关系可用二次曲线方程来拟合,平均每生产100 kg籽粒需N 3.6 kg;施氮量为180 kg/hm²、 分配比例为底肥:拔节肥=7:3时籽粒产量最高,可达4800 kg/hm²(第二年4706 kg/hm²),较CK增产27.6%(第二年增产25.6%)。【结论】综合考虑小麦籽粒产量、 氮吸收利用特性以及土壤中残留氮量,在保证获得较高小麦产量(4650 kg/hm²以上)的前提下,应适当减少氮肥用量,采取氮肥后移及分次施用的方式。本试验条件下带状种植小麦推荐的氮肥用量为N 135～180 kg/hm²,分配比例为底肥:拔节肥=7:3。

Abstract:【Objectives】Strip-relay-intercropping is a classic wheat production pattern in Sichuan, which mainly distributes in upland of hilly areas, with corn constituting as wheat/corn complex planting system. In this study, a two-year field experiment was carried out to study effects of nitrogen(N) fertilizer levels and application stage on N accumulation, distribution and transportation, N usage and its residual in soil, providing scientifical support for the wheat production in the tested area. 【Methods】Chuanmai 42, a major wheat cultivar in local production, was used as material, a two-year field experiment was carried out inRenshou county, Sichuan Province.Spilt-plot experiment was designed, the main-plot was N application rate in four levels (90, 135, 180 and 225 kg/ha), and the sub-plot was N distribution with the ratio of base fertilizer, seedling fertilizer, jointing fertilizer and booting fertilizer in four levels (10:0:0:0, 7:3:0:0, 7:0:3:0, 5:1:2:2), and no fertilizer (CK) as control. 【Results】1) The total N accumulation of aboveground plants at the maturity are increased significantly with the application of nitrogen fertilizer. The N accumulation amounts in vegetative organs at the flowering as well as in leaves and stems at the maturity are increased with the increase of N levels, and the contribution rate of translocated N to grain exhibits the same tendency. The N assimilation and the contribution rate to grain at the post-anthesis are increased first and then declined with the increase of N levels, peaking at the N rate of 135 kg/ha. Simultaneously, the N assimilation at the post-anthesis and the contribution rate to grain are improved effectively by the dressing ratio of 7:3(base fertilizer: jointing fertilizer). On other hand, the N application with dressing ratio of 5:1:2:2(base fertilizer: seedling fertilizer: jointing fertilizer: earing fertilizer) effectively promotes the translocation of storage nitrogen before the anthesis from vegetative organs to grain, increases the residual nitrogen in vegetative organs at the maturity, and decreases the allocation proportion of nitrogen in grain. 2) With the increase of nitrogen levels, the N use efficiency and N productivity of wheat are decreased, while the contents of total N, NO^-₃-N and NH⁺₄-N in soil are increased.Total basal application or top dressing at the elongation stage significantly raise N residues in soil when N application rates are N 180-225 kg/ha, whereas the split dressing and higher dressing ratio could mediate this problem. 3) The relationship between the N application rate and grain yield can be illustrated by a quadratic fitting, i.e. per 100 kg grain needs 3.6 kg nitrogen in average. The highest grain yield of 4800 kg/ha (The following year, 4706 kg/ha) is obtained under this nitrogen strategy in which nitrogen level is 180 kg/ha with the dressing ratio of 7:3 (base fertilizer: jointing fertilizer), which could bring 25.6% additional yield compared with control. 【Conclusions】Comprehensively ansidering the grain yield, N use characteristics and N residues in soil, under the prerequisite of over 4650 kg/ha yield guaranteed, N application rate should be properly decreased and adopt backward and split application pattern. In our case, N application rate of 135-180 kg/ha, basal to devessing at the elongation stage of 7:3 is the recommended.

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