摘要
用地统计学的理论和方法, 分析了渭北旱塬区3种主要土地利用类型农地、苹果地和苜蓿地3个土层深度(0～20、60～80、280～300 cm)的土壤水分空间变化趋势.变异函数分析结果表明,3种土地利用类型的土壤水分具有明显的空间变异特性.在0～20 cm土层,空间变异性尺度为9～16 m,60～80 cm土层为5～12 m,280～300 cm土层为5～10 m,空间变异性程度随尺度变化.自相关尺度为1～17 m,自相关部分的空间变异性在0～20、60～80和280～300 cm分别占总空间变异性的89.95%～94.15%、83.75%～97.64%和85.16%～93.85%,明显大于随机部分的空间变异性.从苜蓿地、苹果地到农地,空间自相关的尺度逐渐增大.各向异性分析表明,农地和苜蓿地在表层(0～20 cm)具有明显的各向异性,而苹果地的土壤水分含量接近各向同性.
Soil moisture is an important variable that significantly affects the hydrological environment of a region. Weibei Upland in southern part of Loess Plateau is a commercial apple base where the increase of apple planting area has seriously affected the regional water cycle. It is necessary to better understand the effects of different land use patterns on the spatial distribution of soil water contents in order to account for the balances of water and energy at Weibei dry highland. In this paper, the principle and methods of geo-statistics were used to investigate the spatial heterogeneity in soil moisture at three soil depths(0~20 cm, 60~80 cm, and 280~300 cm)of different land use types (farmland, apple land, and clover land ) by calculation of semi-variogram at Weibai dry highland in Loess Plateau. Spherical model was used to fit the form of semi-variogram. The typical results showed that there are high degrees of spatial heterogeneity in farmland, apple land and clover land. In 0~20 cm layer, the scale of spatial heterogeneity is 9~16 m, 5~12 m in 60~80 cm layer, and that is 5~10 m in 280~300 cm layer. The degrees of spatial heterogeneity change with this scale. The distance of spatial autocorrelation in soil moisture is found within distances from 1~17 m. The spatial heterogeneities of autocorrelation in total spatial heterogeneity are 89.95%~94.15% (0~20 cm), 83.75%~97.64% (60~80 cm) and 85.16%~93.85%(280~300 cm), respectively, which are obviously more than that of random proportion. The scale of spatial autocorrelation increased gradually from clover land, apple land to farmland. There exists a stronger anisotropic structure in E 0° and N 90° directions in both farmland and clover land (0~20 cm), but apple land in the same direction is close to isotropy.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2005年第z1期33-38,共6页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(40101005)
山东省自然科学基金项目(Q2002E03)
山东省教委项目(J02L01)
关键词
渭北旱塬
地统计学
土壤水分
空间变异性
weibei dry highland
geo-statistics
soil moisture
spatial heterogeneity
