不同植被覆盖条件下黄土土壤温度的变化规律

Soil Temperature Change Law of Loess under Different Vegetation Cover

为了探究黄土高原表层土壤的温度变化规律,选择裸地、植树区和乔草混合区3种样地进行实地测量,运用统计学方法进行为期1 a的浅层土壤温度对比研究。结果表明,春季5 cm处土壤温度显著低于15,30 cm处,夏季浅层土壤温度在22℃左右,秋冬季土壤深度越深温度越高,秋季土壤每15 cm层间增量在1~2℃,冬季则超过2℃;年度日平均土壤温度从高到低排序为植树区>裸土区>乔草混合区,夏季3个样地土壤温度排序为裸土区>植树区>乔草混合区,冬季则相反;地表覆有植被且植被类型越多则该地区植物生长期越长;土壤温度随土壤深度变化规律曲线符合T=alnx+b(4月初至10月底a<1,其他月份a>1)。研究结果可为黄土地区的土壤维护、土地利用方式的选择等提供数据支撑。

To explore the surface soil temperature change law in the Loess Plateau,three kinds of sample plots,bare land,tree planting area and arbor grass mixed area were selected for field measurement,and a one-year comparative study of the shallow soil temperature was conducted by using statistical methods.The results showed that the soil temperature at 5 cm in spring was significantly lower than 15 cm and 30 cm.In summer,the shallow soil temperature was about 22℃.In autumn and winter,the greater the soil depth was,the higher the soil temperature was.The temperature increment of every 15 cm in autumn was 1-2℃,while that in winter was more than 2℃.The order of annual daily average soil temperature was tree planting area>bare soil area>arbor grass mixed area.The order of soil temperature in summer was bare soil area>tree planting area>arbor grass mixed area,but it was opposite in winter.The more vegetation types were covered on the surface,the longer the plant growth period was.The variation of soil temperature with soil depth was T=alnx+b(a<1 from early April to end of October,and a>1 in other months).The results can provide data support for soil maintenance and land use mode selection in Loess area.