高寒荒漠区混播草地土壤水热分布特征

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

探究土壤水热变化规律及特征有助于人工草地高效利用水热资源。利用数理统计和多重分形理论,对比分析了青海省乌兰县藜麦毛苕子混播和燕麦箭筈豌豆混播草地土壤水热变化对降雨的响应及其分布特征。结果表明,降雨对草地土壤含水率的影响具有明显的延迟效应;土壤含水率变化属于中等强度变异,呈“薄尾”分布,土壤含水率的变异主要由高值分布造成,并且主要为短距离变异;与燕麦箭筈豌豆混播相比,藜麦毛苕子混播土壤含水率较高,并且对降雨的表蓄作用较强。降雨对深层土壤温度的影响具有一定的延迟性;土壤温度属于中等强度变异,呈“厚尾”分布,其中0~10 cm土层变异强度最大,深层土壤温度主要为短距离变异,土壤温度变异主要由高值分布造成。与燕麦箭筈豌豆混播相比,藜麦毛苕子混播土壤温度较高,并且受降雨影响较小。综上,混播模式对草地土壤水热的影响存在差异,藜麦毛苕子混播较燕麦箭筈豌豆混播在土壤水热利用方面具有一定优势。该研究结果可为高寒荒漠区人工草地充分利用土壤水热资源提供理论依据。

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.