晋西黄土区不同林龄人工刺槐林下植被及土壤水分特征

以晋西黄土丘陵沟壑区10、15、20a人工刺槐林为研究对象,原生荒草地为对照,采用时空互代法,调查分析坡面刺槐人工林植被恢复过程中林下植被演替和0~400cm土层土壤水分分布情况.结果表明:随着人工刺槐林林龄的增加,林下灌草植被物种丰富度变大,植被结构发育变好;不同林龄刺槐林地与荒草地土壤平均含水量由大到小顺序为荒草地(16.61%)、20a刺槐林地(10.08%)、15a刺槐林地(9.54%)、10a刺槐林地(8.52%);随着刺槐林龄的增加,土壤水分随坡位下降而增大的趋势有所改变,成熟刺槐林对坡面土壤水分空间分配的调节作用明显;人工刺槐林土壤水分沿垂直剖面变化方式与原生荒草地差异明显,15a以上刺槐林对100cm以下土壤水分的影响已基本稳定;人工刺槐林的生长造成了严重的林地土壤水分亏空,随着林龄的增长0~200cm土层土壤水分条件有所改善,但深层土壤(200~400cm)没有明显的恢复迹象.研究结果为黄土区植被恢复和刺槐林的经营管理提供了科学依据.

Plant diversity and soil moisture of artificial Robinia pseudoacacia forest in loess region of western Shanxi Province

Plant diversity and soil moisture distribution at 0~400 cm depth were analyzed for slope artificial forest of Robiniapseudoacacia (ARF)at 10a,15a,20a,waste grassland was used as control.Plant diversity below forest has been found to increase with forest age,and vegetation structure has improved.The order of total soil moisture was:waste grassland (16.61%)>20 a (10.08%)>15 a (9.54%)>10 a (8.52%). With increased forest age,the trend of soil moisture increase with drop in slope is restrained.Mature RPF has a significant effect on slope soil moisture distribution.Vertical variation in soil moisture was markedly different between ARF and waste grassland,above 15a old ARF has a stable effect on soil moisture below 100cm.ARF leads to serious soil moisture deficit.With increased forest age,moisture of 0~200 cm soil is improved,but there is no recover sign for 200~400 cm soil.This work will help to guide eco-environment construction and management of Robinia pseudoacacia in the loess region of western Shanxi Province.