在阿鲁科尔沁旗沙地研究了不同种植年限苜蓿根系形态及地下生物量变化。结果表明，随着种植年限的增加，苜蓿主根长度和侧根数量呈先增加后降低的趋势，种植3 a的主根长度和侧根数量均最多，主根长度较种植当年长45.53%(P < 0.05)，侧根数量较种植当年的增加42.01%(P < 0.05)；苜蓿根颈直径不断增粗，较种植当年增加70.27%，增加显著。0～10 cm土层的地下生物量呈先增加后降低趋势，种植2 a的地下生物量鲜重最大，较种植当年增加12.00%(P < 0.05)，然后随种植年限的增加逐渐降低。

A study was conducted to determine the root morphology and underground biomass of alfalfa with different planting years in Arhorchin Banner. The results showed that with the increase of planting years the length of taproots and the number of lateral roots increased first and then decreased， and both reached the maximum at 3 years of planting. Compared with the plants in the same year， the length of taproots significantly longer than 1 year was 45.53%(P < 0.05) and the number of lateral roots was 42.01%(P < 0.05). The root neck diameter of alfalfa was thickened continuously， which was 70.27% thicker than that of alfalfa in planting 1 year. In the 0-10 cm soil layer， the underground biomass were first increased and then decreased. The fresh weight of the underground biomass reached the maximum at planting 2 years， which was significantly heavier than that of 12.00% in planting 1 year (P < 0.05)， and then decreased gradually with the increase of planting years.

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