摘要
土壤水分是干旱半干旱地区生态建设的主要限制因子,在有限降雨条件下,深层土壤水分对土地利用和植被恢复的响应特征是植被恢复能否实现可持续发展的关键。为明确深层土壤水分时空变化特征,在黄土高原北部六道沟小流域的柠条、山杏、苜蓿、撂荒、沙地、沟道和农地分别布设960 cm深的中子管,利用中子仪(CNC503DR)测定了2014-2017年土壤水分含量共计19次。研究结果表明:0-200 cm范围内,柠条处理土壤含水量最低(平均含水量9.5%),其次分别是沙地(10.4%)、苜蓿(10.6%)、山杏(12.6%)、撂荒(13.0%)、农地(14.2%),侵蚀沟沟底土壤含水量最高(15.6%)。沙地处理200 cm-960 cm土壤水分平均值仅为6.6%,其次是山杏(10.7%)、苜蓿(11.6%)、柠条(13.5%)、撂荒(16.1%)、农地(18.0%),侵蚀沟沟底土壤含水量高达21.0%(200-460 cm)。侵蚀沟沟底点位土层深度只有460 cm,但是380-460 cm土层土壤含水量达到了25%以上。农地、柠条和撂荒处理中900 cm以下土壤含水量呈明显的增加趋势,特别是农地处理,960 cm深度处土壤含水量高达30.3%。随着土层深度的增加,土壤含水量标准差逐渐降低且趋于稳定。土壤质地与土壤水分标准差和变异系数呈显著相关,土壤含水量标准差随粘粒含量的增加呈指数增加(R^(2)=0.5134),变异系数则呈对数减少(R^(2)=0.7274)。各处理粘粒含量差异明显,沙地处理中0-400 cm土层土壤粘粒含量较为稳定(9.2%),400 cm以后大幅下降(1.8%)。侵蚀沟底土壤粘粒含量最高,0-460 cm土层粘粒含量平均值达到了12.3%.0-960 cm土壤含水量随粘粒含量的增加呈指数关系显著增加(R^(2)=0.7097)。对0-200 cm和200-960 cm土层土壤粘粒含量和土壤含水量分别做回归分析,R^(2)值分别为0.4138和0.7684。表层土壤含水量受降水、植被和土壤质地的多重影响,而土壤粘粒含量是影响深层土壤含水量及其稳定性的决定性因素,相关研究结果可以为黄土高原地区土壤水资源高效管理和利用及生态建设可持续发展提供科学指导。
Soil moisture is the main limit for ecology construction in the arid and semi-arid regions.Due to the limited rainfall,the response of deep soil moisture to land use and vegetation restoration is the key factor to sustainable development of vegetation restoration.In order to reveal the spatial and temporal variation of deep soil moisture,neutron tubes were inserted in the area of caragana(Caragana Korshinskii),alfalfa(Medicago Sativa),apricot(Armeniaca sibirica),fallow,sandy land,gully and crop land in the Liudaogou watershed of the Loess Plateau.A total of 19 times of soil moisture content from 2014 to 2016 were determined by neutron meter(CNC503DR).The results showed that soil planted with caragana occupied the lowest soil water content(mean 9.5%),followed by sandy land(10.4%),alfalfa(10.6%),apricot(12.6%),fallow(13.0%),cropland(14.2%).The soil water content was highest in the eroded gully bottom(15.6%).The average soil water content of 200-960 cm in sandy land was only 6.6%,followed by apricot(10.7%),alfalfa(11.6%),caragana(13.5%),fallow(16.1%),cropland(18.0%),and gully bottom 21.0%(200-460 cm).The soil depth of at the erosion gully bottom was only 460 cm,but the soil moisture content in the 380-460 cm soil layer reached more than 25%.The soil water content in the soil layer below 900 cm in cropland,caragana and fallow treatments showed an obvious increasing trend,especially in the cropland plot,the soil water content at 960 cm depth reached 30.3%.With the increase of soil depth,the standard deviation of soil moisture content decreases and tends to be stable.Soil moisture was significantly associated with standard deviation and coefficient of variation and soil texture.With the increase of clay content,the standard deviation of soil water content exponentially increased(R^(2)=0.5134),and the variation coefficient of soil moisture content logarithmic decreased(R^(2)=0.7274).The soil clay content differed obviously among these treatments.The clay contents is relatively stable within 0-400 cm soil layer in the sand plot(average 9.2%),however,they declined sharply in the layer of 400-960 cm(average 1.8%).The soil clay content in eroded gully bottom was the highest,and the average clay content in 0-460 cm reached 12.3%.The soil water content of 0-960 cm increased exponentially with the increase of clay content(R^(2)=0.7097).The soil moisture were highly depended on soil clay content,the R^(2) values were 0.4138 and 0.7684 in 0-200 cm and 200-960 cm,respectively.Soil moisture in the shallow layer is affected by rainfall,vegetable,soil texture and so on.While the deep soil moisture content and its stability is mainly controlled by soil clay content.Our results can provide scientific guidance for efficient management and utilization of soil water resources and sustainable development of ecological construction in the Loess Plateau.
作者
张梦杰
孙树臣
ZHANG Mengjie;SUN Shuchen(Hunan Institute of Water Resources and Hydropower Research,Changsha 410007,China;School of Environment and Planning,Liaocheng University,Liaocheng 252059,China)
出处
《聊城大学学报（自然科学版）》
2021年第4期103-110,共8页
Journal of Liaocheng University:Natural Science Edition
基金
国家自然科学基金项目(41701243)
聊城大学博士启动基金项目(318051748)资助。
关键词
立地条件
土壤水分
时空分布特征
土壤质地
黄土高原
site condition
soil water
spatial and temporal distribution characteristics
soil texture
Loess Plateau
