Sustained rice yields and decreased N runoff in a rice-wheat cropping system by replacing wheat with Chinese milk vetch and sharply reducing fertilizer use

文献类型： 外文期刊

第一作者： Qiao, Jun

作者： Qiao, Jun;Zhou, Wei;Yan, Tingmei;Zhao, Dong;Yang, Linzhang

作者机构：

关键词： Environmental sustainability; Paddy rice; Green manure; N runoff losses; N gradient

期刊名称：ENVIRONMENTAL POLLUTION （ 影响因子：8.071； 五年影响因子：8.35 ）

ISSN： 0269-7491

年卷期： 2021 年 288 卷

页码：

收录情况： SCI

摘要： Pollution from the paddy fields has posed a threat to surface water quality, and the reactive N in runoff has been recognized as the dominant contributor. In the rice-wheat systems of eastern China, replacing wheat (Triticum aestivum) with Chinese milk vetch (CMV) (Astragalus sinicus) is known to reduce total fertilizer N use and associated N losses during winter; however, the function of the rice-CMV system in controlling the N runoff loss was overlooked during the summer rice-growing season. Over 6 years, we monitored soil mineral N, plant N accumulation, rice grain yield, N agronomic efficiency (AE(N)), and N runoff in rice-CMV fertilizer N rate-response experiments and made comparisons with the conventional N inputs in rice-wheat rotation. Aboveground CMV residues added 65-116 kg N ha(-1) yr(-1); therefore, by adjusting the fertilizer time, the rice in this system required 44-56% less N fertilizer to produce rice yields equivalent to the 270 kg N ha(-1) (district average, C270) used in the rice-wheat system. In all fertilizer N application treatments, 120 kg ha(-1) seemed to be the threshold that ensured the soil N supply, the N accumulation at rice critical stages, and consequently, the current level rice yield. The corresponding runoff N averaged 9.3 kg ha(-1) season(-1), which was 51.8% less than that in C270 (19.3 kg ha(-1) season(-1)). Cumulative N runoff (total N and NH4+-N) correlated strongly with fertilizer N input for any single year (sample size = 108, P < 0.01). Application of 30-120 kg fertilizer N ha(-1) gave an equivalent AE(N), which indicated that the integration of CMV and fertilizer N could increase the agronomic efficiency of N fertilizer applied to the rice. Rotating paddy rice with CMV instead of wheat, together with the suitable adjustment of N fertilizer, could sustain rice yield and gain the utmost environmental benefits from rice-based agroecosystems.

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