间作系统刈割三叶草对小麦氮素供给的影响(英文)

Impact of Cutting a Clover Crop on the Nitrogen Supplied to Winter Wheat in an Intercropping System

三叶草在小麦-三叶草间作系统中起到为小麦提供氮肥的重要作用。中国科学院禹城综合试验站的田间试验评价了小麦-三叶草间作系统中刈割三叶草对三叶草固氮以及向小麦转移氮素的影响。利用15N自然丰度法测定了小麦-三叶草间作系统中氮素的转移。结果表明,整个生长季三叶草向小麦转移的氮量在34.4–57.5 kg·ha-1之间。与不刈割相比,刈割三叶草增加了土壤中累积的氮素,同时减少了小麦茎叶中氮浓度。将刈割的茎叶覆盖到小麦行间导致小麦茎叶中氮浓度的降低。该研究提供了小麦-三叶草间作系统中氮素从三叶草向小麦转移的量,为该间作系统在华北平原的推广提供参考依据。

The major function of clover in a winter wheat–white clover intercropping system is to supply nitrogen （N） for the wheat. A field experiment was conducted at Yucheng Comprehensive Station of the Chinese Academy of Sciences, to evaluate the effect of cutting white clover on N fixation and the transfer of fixed N to the associated winter wheat. A method of 15N natural abundance was used to determine the nitrogen dynamics in the intercropping system. The results showed that the amount of N transferred from the clover to the wheat, throughout the growing season, varied between 34.4 and 57.5 kg ha-1. Compared to leaving the clover standing, cutting the clover increased the amount of N that accumulated in the soil and also resulted in reduced N concentrations in the leaves and stems of the wheat. Using the cut clover as mulch between wheat rows led to decreased N concentrations in the wheat plants’ leaves and stems. The present study provides preliminary information on the amount of N transferred from clover to wheat in an intercropping system.