草地雀麦种植对坡地土壤水分动态变化的影响

Effect of Meadow Brome(Bromus riparius) Planting on Soil Moisture Dynamic Changes

选择15°坡地设置草地雀麦种植试验小区,并以裸露地为对照,在自然降雨条件下观察草地雀麦生物学特性及坡地土壤含水量变化,研究草地雀麦种植对坡地土壤水分动态变化的影响。结果表明：草地雀麦种植对坡地土壤水分动态变化影响显著,且地下生物量越大影响越大。在北京地区草地雀麦种植2年后地上生物量达4412.7kg/hm^2,0-30cm地下生物量达3325.3kg/hm^2,且0-10cm土层地下生物量是草地水土保持功能发挥的主要组成部分。北京地区土壤水分变化较为明显的时期主要在3-10月份,其动态变化大体可分为雨季前期（3-6月）和雨季（7-10月）两个阶段,其中,雨季前期土壤含水量较低,草地雀麦种植可以减缓坡地0-60cm深度土壤含水量的下降,并以0-20cm土层作用最大,维持土壤含水量在11.5%-12.0%之间;雨季降雨明显增加时,草地雀麦可以促进坡地土壤水分吸收达到相对较高的状态,并在土壤含水量高于23%以上后,加速0-60cm土层尤其是0-20cm土层土壤水分散失,维持土壤含水量在17.5%以下。

In natural rainfall conditions,the meadow brome was planted in runoff-plots on the 15 degree slope,and meadow brome biological characteristics and soil moisture dynamic changes were observed compared with CK of the bare slope,then the effect of meadow brome planting on soil moisture dynamics changes in the slope was studied.The results showed that the effects of meadow brome planted on the slope had a significant effect on soil moisture dynamics,and the more meadow brome underground biomass increasing,the more effect.The above-ground biomass of meadow brome growing for two years in Beijing was 4412.7kg/hm^2 and underground in the 0～30cm soil was 3325.3kg/hm^2.And underground biomass in the 0～10cm soil was more important to soil and water conservation.In Beijing,soil moisture changes occurred obviously during March to October,which can be divided into two periods according to the dynamic characters including early rainy season（March - June） and rainy season（July - October）.In early rainy season in which soil moisture was low,meadow brome may keep soil moisture in 0～60cm soil,especially in 0～20cm soil,and soil moisture in slope can be kept in level of 11.5% to 12.0%.When rainfall was increased obviously in rainy season,meadow brome can promote soil moisture increase in the slope soil,and soil moisture was more than 23%,soil moisture in 0～60cm,especially in 0～20cm,was lost quickly,soil moisture was kept at less than 17.5%.