干旱区生态环境知识资源中心

Although litter has long been recognized as being important in arid rangeland water balance, little information exists regarding water balance in the litter layer. Using a rainfall simulator and litter manipulations in the field, the impact of litter on rainfall interception and the maintenance of superficial soil water content were investigated in an arid rangeland in Khabr National Park in south-eastern Iran. Litter mass was sampled in ninety 1 m(2) quadrats randomly placed throughout the site. After determining the intensity of typical storms in the region to be 20 mm/h, amount of rainfall interception loss by litter was estimated using wetting and drying curves of litter. Water content of superficial soil (top 5 cm of top soil) was measured in bare soil and in soil covered by litter. On average, 0.64% or 5 mm of simulated rainfall was intercepted by litter. We show that litter decreases evaporation of superficial soil water content and retains water in the soil for longer periods after rainfall. Our results indicate the need of litter-based field management programs in arid and semi-arid rangelands of Iran.