Nitrogen release from incorporated 15N-labelled Chinese milk vetch (Astragalus sinicus L.) residue and its dynamics in a double rice cropping system

Abstract

Chinese milk vetch (Astragalus sinicus L. CMV), a leguminous cover crop, has been shown to provide N benefits to rice crops, but little is known about the pathway of incorporated CMV and its N dynamics. In this study, effects of CMV under different application treatments (incorporated alone, applied in conjunction with urea fertilizer and applied with ryegrass (Lolium multiflorum Lam.)) on N dynamics, rice yields and N uptake were investigated and compared with those of chemical fertilizer (CF) and no fertilizer (NF) in a double rice cropping system. Nitrogen release from incorporated CMV residue was quantified by using a bag method. Nitrogen dynamics of CMV were evaluated by using 15N-labelled fresh CMV tops and compared with those of CF (15N-labelled urea). CMV residue decomposition pattern and its N release pattern followed a single exponential decay model, with 87.8–89.5 % of the applied CMV decomposed and 95.1–96.1 % of the original N released in the double rice season (177 days after fertilizer application). CMV treatments had higher rice N uptake efficiency than CF (39.2–51.3 % vs. 29.9 %) at the sum of early and late rice seasons. Rice yield, N accumulation and mineral fertilizer efficiency in CMV treated treatments were higher than those in CF. After two consecutive rice seasons the amounts of residual N remained in the soil were higher in the CMV treated fields than in CF (29.4–33.2 % vs. 14.1 %). CMV can be considered an efficient N source alternative to chemical fertilizer in double rice cropping systems.

DOI: 10.1007/s11104-013-1808-8

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Cite this paper

@article{Zhu2013NitrogenRF, title={Nitrogen release from incorporated 15N-labelled Chinese milk vetch (Astragalus sinicus L.) residue and its dynamics in a double rice cropping system}, author={Bo Zhu and Lixia Yi and Yuegao Hu and Zhaohai Zeng and Chaowen Lin and Haiming Tang and Guangli Yang and Xiaoping Xiao}, journal={Plant and Soil}, year={2013}, volume={374}, pages={331-344} }