Non-leguminous winter cover crop and nitrogen rate in relation to double rice grain yield and nitrogen uptake in Dongting Lake Plain, Hunan Province, China

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• 作者：Bo ZHU^a ; ^b ; ^{1984zhubo@163.com" class="auth_mail" title="E-mail the corresponding author} ; Li-xia YI^a ; He-shui XU^b ; Li-mei GUO^b ; Yue-gao HU^b ; Zhao-hai ZENG^b ; ^{zengzhaohai@cau.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Fu CHEN^a ; ^b ; Zhang-yong LIU^a
• 关键词：double rice ; grain yield ; N uptake ; N use efficiency ; winter cover crop
• 刊名：Journal of Integrative Agriculture
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：15
• 期：11
• 页码：2507-2514
• 全文大小：460 K

文摘

Annual ryegrass (Lolium multiflorum Lam.), a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little is known about its effects on rice grain yield and rice N use efficiency. In this study, effects of ryegrass on double rice yield, N uptake and use efficiency were measured under different fertilizer N rates. A 3-year (2009–2011) field experiment arranged in a split-plot design was undertaken. Main plots were ryegrass (RG) as a winter cover crop and winter fallow (WF) without weed. Subplots were three N treatments for each rice season: 0 (N₀), 100 (N₁₀₀) and 200 kg N ha⁻¹ (N₂₀₀). In the 3-year experiment, RG reduced grain yield and plant N uptake for early rice (0.4–1.7 t ha⁻¹ for grain yield and 4.6–20.3 kg ha⁻¹ for N uptake) and double rice (0.6–2.0 t ha⁻¹ for grain yield and 6.3–27.0 kg ha⁻¹ for N uptake) when compared with WF among different N rates. Yield and N uptake decrease due to RG was smaller in N₁₀₀ and N₂₀₀ plots than in N₀ plots. The reduction in early rice grain yield in RG plots was associated with decrease number of panicles. Agronomic N use efficiency and fertilizer N recovery efficiency were higher in RG plots than winter fallow for early rice and double rice among different N rates and experimental years. RG tended to have little effect on grain yield, N uptake, agronomic N use efficiency, and fertilizer N recovery efficiency in the late rice season. These results suggest that ryegrass may reduce grain yield while it improves rice N use efficiency in a double rice cropping system.