陈永岗 杨正荣 郭天斗 柴锦隆 王军 吴召林 马晓东 安雅君 陈本建

摘要：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。

关键词：苜蓿;不同种植年限;地下生物量;根系形态

中图分类号：S541      文献标志码：A      文章编号：1001-1463（2021）08-0053-06

doi：10.3969/j.issn.1001-1463.2021.08.013

Abstract：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.

Key words：Alfalfa;Different planting years;Below ground biomass;Morphology of root system

近年来，随着我国牧草产业在“粮经饲”种植结构比例中的不断加大[1 ]，“中国草都”内蒙古赤峰市阿鲁科尔沁旗沙地苜蓿种植区面积不断增大。但由于该地区特殊地理位置及气候条件，苜蓿越冬难，成为限制该地区苜蓿产量的主要因素，研究解决该地区苜蓿越冬难问题显得尤为重要。生物量作为植物生长的基础和营养物质来源，可以反映植物对有机物质和能量的积累情  况[2 ]。植物通过生物量分配将周围环境中获得的营养物质通过库源结构储存于根、茎、叶、花、果等器官，供植物生长所用[3 ]。植物生物量分配与自身特性及生长环境条件有关[4 ]，在不同生长条件下表现不同的生长特性和物质分配规律[5 ]。根系是植物吸收、转化、储存营养和水分的重要器官，具有支持植株和释放分泌物的功能[6 ]，其生长的健康与否直接影响植物的生物量和对环境的适应能力[7 ]。根系会随植株生长向下延伸至深层土壤中，侧根不断向四周扩散生长，继而获得更多营养和水分，在特定生长环境下呈现出特定的根系形态。……