以太湖流域杨树－冬小麦间作（简称杨麦间作）系统和冬小麦单作地为研究对象，研究了不同施氮量下杨麦间作系统中冬小麦和杨树细根的时空分布特征与冬小麦单作系统之间的差异，探讨林木根系在减少径流中养分流失方面的作用。结果表明：（1）单作冬小麦根长密度和单位土体根干质量均大于间作系统，间作系统中越靠近林带的冬小麦根长密度和单位土体根干质量越小。（2）单作地和间作系统冬小麦根长密度和单位土体根干质量最大值均出现在灌浆期。（3）随着施氮量的加大，冬小麦和杨树细根根长密度和单位土体根干质量均有所增加，且在间作系统中＞40～80 cm土层杨树细根根长密度和根干质量所占比例增加。（4）间作系统减少了硝态氮随淋溶的流失量，灌浆期减少幅度为49�08％～55�49％。%The method of stratified digging was adopted to study temporal and spatial distribution of fine roots in a four⁃year old poplar⁃winter wheat intercropping system relative to nitrogen fertilization and its difference from that in the winter wheat mono⁃cropping system, and to explore effect of the intercropping system reducing nutrient loss with runoff. Results show that ( 1) the winter wheat in the mono⁃cropping system was higher than that in the intercropping system in terms of fine root length density and root dry weight per unit of soil;( 2) the peaks of root length density and root dry weight per u⁃nit of soil appeared during the wheat milking stage in both systems;( 3) with increasing nitrogen application rate,both the wheat and the poplar increased in fine root length density and root dry weight per unit of soil and for poplar the increase mainly occurred in the > 40- 80 cm soil layers; and ( 4 ) intercropping reduced nitrogen loss with leaching by 49�08%-55�49%.
展开▼
