杉木连作,第二代杉林生长有明显衰退现象,据调查,比第一代杉木茁积量下降10—50％。针对上述问题,我们对杉木连作地进行了施肥试验,地点选择在国营龙潭林场,经过六年多的实践,取得了良好的效果。一、试验情况试验地选取海拔高350米,坡度28°,沙页岩发育成的山地红壤,pH4.5,立地条件中等的杉纯林采伐迹地。面积一公顷,进行 Cunninghamia lanceolata continuous cropping, the second generation of Chinese fir growth significantly declining phenomenon, according to the survey, than the first generation of Chinese fir fell 10-50%. In response to the above problems, we conducted a continuous cropping experiments Fir, the location selected State-run Longtan Forest Farm, after more than six years of practice, and achieved good results. First, the experimental conditions Experimental selection of an altitude of 350 meters, the slope of 28 °, sand shale developed mountain red soil, pH4.5, the site conditions of the middle fir cuttings. One hectare in area