杉木为浅根树种,其主根多分布于40厘米左右的土层中,毛细很多分布在20米米左右的土层中.因此,如能使这部份土壤保肥、透水、通气,就使杉木速生丰产有了保证.我场大山工区杉木林地,土壤属粉沙性红黄土,表土贫瘠,粘重,透水、通气性能很差.为了改良林地土壤,为杉木生 Cunninghamia lanceolata is a shallow-rooted tree species whose main roots are mostly distributed in a soil layer of about 40 centimeters and many of which are distributed in a soil layer of about 20 meters. Therefore, if this part of the soil is fattened, permeable and aerated, Fast-growing and high-yield has been guaranteed .Industry Dashan District fir woodland, the soil is pink sandy loess, topsoil barren, sticky weight, water permeability, poor aeration performance .In order to improve the forest soil,