黄土集水造林地土壤热特性的研究

Study on soil thermal properties in forest land of catchment in loess.

1998年 5～ 1 0月在山西省方山县北京林业大学径流林业试验场 ,采用KADEC U2型自记土壤温度仪 ,对刺槐林地 3种集水处理坡面的土壤进行 2 ,1 0 ,2 0 ,5 0cm深度土壤温度的连续全天观测 .结果表明 :各处理坡面土壤生长季平均容积热容量为 :拍光坡面 1 4 44J·cm-3 ·K-1,拍光 +地衣坡面 1 394J·cm-3 ·K-1,自然坡面 1 2 73J·cm-3 ·K-1;平均导热率依次为 0 35 2 ,0 34 4,0 31 1J·(cm·℃·min) -1;平均土壤热扩散率为 0 2 44～ 0 2 47cm2 ·min-1.拍光压实后喷涂引植地衣、苔藓 ,可有效缓解地表裸露后产生的负影响 ,在生长季可降低表层均温 0 2～ 1 5℃ ,降低最高表层土温 2 7～ 4 0℃ ,降低表层土温日较差 2 5～ 3 7℃ ,降低土壤热通量 1 1 %～ 2 5 % ,有效降低土壤蒸发 4%～ 1 5 % .实行拍光压实兼喷涂引植地衣、苔藓的集水造林技术 ,经济实用 ,对土壤水热环境的负面影响小 。

By KADEC U2 auto soil thermometer,the observation on soil temperature of 2?cm,10?cm,20?cm and 50?cm depth was carried out from May to Oct.in 1998,at three kinds of catchment stands of Robinia pseudoacacia in Fangshan County,Shanxi Province.The results are as follows:in growing season the average volume heat capacity is 1.444?J·cm -3 ·K -1 at the stands in which soil was pressed, 1 394?J·cm -3 ·K -1 in which soil was pressed and then was spraied with lichen coat,and is 1 273?J·cm -3 ·K -1 at the stands of original state.The average thermal conductivity,in the above order,is 0 352?J·(cm·℃·min) -1 ,0 344?J·(cm·℃·min) -1 and 0 311?J·(cm·℃·min) -1 .The average thermal diffusivity is 0 244～0 247cm 2·min -1 .By pressing soil and using lichen coat,the reforesting technique of catchment can lighten the bad effect of nudity soil,and can lower down average topsoil temperature by 0 2～1 5?℃, maximum topsoil temperature by 2 7～4 0?℃, topsoil temperature amplitude by 2 5～3 7?℃, and depress 11%～25% soil thermal flux and 4%～15% soil evaporation.This forestation method has less bad influence on environment variables of soil water and heat,is economical and valuable.