黄土丘陵沟壑区前期降雨指数构建及其径流效应研究  

Study on the Antecedent Precipitation Index （API） Design and Its Runoff Effect in a Loess Hilly Area

作　　者：卫伟[1,2] 陈利顶[1] 吕一河[1] 傅伯杰[1] 

机构地区：[1]城市与区域生态国家重点实验室、中国科学院生态环境研究中心,北京100085 [2]中国科学院研究生院,北京100039

出　　处：《水土保持研究》2007年第4期368-371,共4页Research of Soil and Water Conservation

基　　金：国家自然科学基金项目（40321101;30570319）;国家“十五”科技攻关资助项目（2001BA606A-03）.

摘　　要：前期降雨指数可以作为量化和测算一个区域内降雨发生时前期土壤水分含量的有效指标。而前期土壤水分状况对地表径流的启动起着重要的作用。因此,构建、量化前期降雨指数并探讨其与地表径流之间的关系极为重要。基于甘肃定西安家沟小流域内（35°35′N,104°39′E）的多年径流小区水文监测数据,在前人的研究基础上构建了半干旱黄土丘陵区的不同土地利用/植被覆盖下的前期降雨指数,并探讨了它们与对应地表径流量之间的关系。结果发现：（1）不同土地利用/植被覆盖下的前期降雨指数存在差异,即不同植被类型下的土体水分含量存在差异,再次验证了土地利用在一定程度上能够起到改变土壤蓄水能力和水土保持的效果;（2）前期降雨指数中,以灌丛的变异系数最小,松林地变异最大,自然草地变异小于人工草地。表明不同土地利用下的土体物理性状稳定性存在差异,以灌丛最佳,松林地最差,可能和其林下土壤板结有关。（3）不同土地利用/植被覆盖下的前期降雨指数与径流量关系依次为：灌丛林下为极为显著正相关;自然草地和人工草地均为显著相关、并以自然草地相关性更好;松林地和坡耕地的前期降雨指数和径流无明显相关关系。建议在植被恢复和格局调整中将灌丛（沙棘）作为首选的先锋植物种。The antecedent precipitation index （API） can be used as an effective tool to quantify and represent the previous soil water conditions. Previous soil water however, plays an important role in surface runoff generation. Studying and discussing the relationship between them is therefore very important for controlling soil and water loss. On the basis of former scholars＇ efforts and many years of monitored hydrological data in Anjiagou catchment （35°35＇N, 104°39＇E）, Dingxi, Gansu province, the API and its relations with corresponding runoff amounts under different land use/vegetation coverage in the loess hilly area are separately designed and discussed. The results are as follows. Firstly, the antecedent precipitation indices among different land use/vegetation cover differ. This indicates that land use can change the soil water holding capacity and induced water reserving ability. Secondly, among the five land use/cover types, the coefficient of variation of API in scrubland is the smallest, followed by natural grassland and artificial grassland. Pine woodland remains the largest variation, which may due to soil hardening un- der the pine forest. Thirdly, the correlations between API and runoff yields under different land use/vegetation cover are in the order of： shrubland〉natural grassland〉artificial grassland. Pine woodland and slope farmland, however, have no significant correlation between runoff and API. We suggest thus, shrubland （seabuckthorn） should be used as the preferred species for practical vegetation restoration and pattern adjustment.

关 键 词：黄土丘陵沟壑区 前期降雨指数 地表径流 效应 

分 类 号：S152.7[农业科学—土壤学] S714[农业科学—农业基础科学]