优材更替生态公益林水土保持效益研究

Study on benefit analysis of soil and water conservation about excellent material change of ecological forest

以湖南省洞口县月溪国有林场生态公益林为研究对象,对其成熟林优材更替前后水土保持效益进行了研究。结果表明:1#更替模式(新造杉木纯林)和2#更替模式(新造杉木+樟树混交林)的地表径流量、泥沙流失量都比3#更替模式(CK,未砍伐杉木过熟林)大2～3倍;前者实施了挖穴造林,破坏了地表土壤结构,但水土流失系数没有超出允许浸蚀量,说明采取小块状更新、穴垦整地的更新方式对水土流失影响不严重。在立地条件基本一致的条件下,影响水土流失的关键因子是降水强度,地表植被的影响次之。影响地表径流量、泥沙流失量的另一因素是雨季降雨量,因此,防治水土流失关键期在雨季。混交林的土壤在日降水强度为7～11级时,对雨水具有较强的抗侵蚀作用。

Study on benefit analysis of soil and water conservation about excellent material change of ecological forest was taking Yuexi State-owned Forest Farms in Dongkou County as study area. The results showed that the surface runoff, soil loss amount of 1# （ the new afforestation pure forest of Chinese fir）, 2# （ the new afforestation mixed forest of Chinese fir and Cin^mum camphora） runoff plot are 2 - 3 times lager than 3# runoff plot （CK）. The former implementation of digging planting and destruction of surface soil structure, but the erosion of soil erosion coefficient does not exceed the allowed amount, indicating take a small block update, the update points cultivated land preparation methods on soil erosion are not severely affected. Under the same conditions, the key factor which affects the soil erosion is rainfall intensity, vegetation factor, followed by. Another factor about soil erosion is rainfall during the rainy season, therefore, the critical period of erosion control is in the rainy season. It is important significance for the mixed forest for the in- tensity of daily precipitation levels for the 7 -11 soil erosion corrosion.