平茬对塔里木沙漠公路沙拐枣防护林生长与土壤水盐分布的影响

对塔里木沙漠公路防护林示范段老化衰败的沙拐枣林分进行平茬复壮试验,并对平茬后沙拐枣生长与土壤水盐分布进行动态监测.结果表明:两次平茬后,沙拐枣萌蘖株的株高、冠幅、地径和萌蘖数均迅速增加.与对照相比,平茬后第3年,沙拐枣萌蘖株的平均株高超过对照,冠幅和最大地径分别达到对照的92.0％和73.0％;萌蘖株的枝鲜质量、同化枝鲜质量、枝干质量、同化枝干质量、地上部分总鲜质量和总干质量分别达到对照的80.0％、115.0％、80.0％、116.0％、93.5％和88.0％.平茬4年后地上生物量达到甚至超过对照.平茬能增加土壤含水量,且影响达到极显著水平;平茬能降低土壤含盐量,但影响不显著.对老化衰败的沙拐枣林进行重复平茬,能增加其土壤含水量,降低根系分布层土壤含盐量,有效促进其复壮更新.

Effects of stumping on Calligonum mongolicum shelterbelt growth and soil moisture and salt distribution along Tarim Desert Highway, Xinjiang of Northwest China

In order to ensure the stability and sustainability of the Calligonum mongolicum shelterbelt along Tarim Desert Highway, the aged C. mongolicum was stumped to investigate its growth and soil moisture and salt distribution. After stumping twice, C. mongolicum grew rapidly in its height, crown width, maximum basal diameter, and sprout number. Three years after stumping, the average height of the sprouts exceeded the control (no stumping), and the crown width and maximum basal diameter was 92.0% and 73.0% of the control, respectively. The fresh mass of the branches and assimilating branches, their dry mass, and the total fresh mass and dry mass of the aboveground parts reached 80.0%, 115.0%, 80.0%, 116.0%, 93.5%, and 88.0% of the control, respectively. Four years after stumping, the aboveground biomass surpassed the control. Comparing with the control, stumping increased the soil moisture content significantly and decreased the soil salt concentration. It was suggested that, to stump the aged C. mongolicum repeatedly could increase the soil moisture content and decrease the soil salt concentration in root zone, and effectively promote the rejuvenation and renewing of C. mongolicum.