Soil Water and Heat Distribution Characteristics of Mixed Artificial Grassland in Alpine Desert Area

Exploring variation laws and characteristics of soil water and heat helps to efficiently utilize water and heat resources in artificial grasslands．Based on mathematical statistics and multifractal theory, response and distribution characteristics of soil water and heat variations to rainfall were compared and analyzed in Wulan County, Qinghai Province．Results showed that influence of rainfall on soil moisture content had obvious delayed effect．Variation of soil moisture content was of moderate intensity with a "thin-tailed" distribution, and mainly caused by distribution of high values with a short-distance variation．Compared with pattern of mixed sowing oats and arrows, soil moisture content was higher and effect by rainfall was stronger in pattern of mixed sowing peas and quinoa．Effect of rainfall on soil temperature of deep depth had a certain delay．Soil temperature belonged to moderate intensity variation showing a "thick tail" distribution, among which soil temperature in 0～10 cm soil layer had the highest variation intensity．The deep soil temperature was mainly short-distance variation, and variation of soil temperature was mainly caused by high value distribution．Compared with pattern of mixed sowing oats and arrows, soil temperature was higher and effect by rainfall was less in pattern of mixed sowing peas and quinoa．In conclusion, there were differences in effects of mixed sowing patterns on soil water and heat．Pattern of mixed sowing peas and quinoa had more advantages in soil water and heat utilization than pattern of mixed sowing oats and arrows．The results could provide a theoretical basis for full utilization of soil water and heat resources in artificial grasslands in alpine desert regions．