A Study on Soil Erosion and Nutrient Loss in Chinese Fir Plantation

A long term study was conducted on the soil and water conservation as well as the nutrient cycling in the juvenile, middle aged and pre matural Chinese fir plantation located in three forest farms attached to the Subtropical Forestry Experimental Center, Chinese Academy of Forestry (CAF) in Fenyi County of Jiangxi Province from 1984 to 1996.The results showed that the degree of soil erosion and nutrient loss occurred in Chinese fir plantation decreased with the increase of plantation age from juvenile to middle aged and to pre mature ones.For example, in the juvenile plantation the surface runoff was 546.0 m3·hm-2, soil loss was 1005.0 kg·hm-2, while in the middle aged plantation the surface runoff was 506.98 m3·hm-2, the soil loss was only 180.7 kg·hm-2 and in the pre mature plantation the surface runoff was 477.25 m3·hm-2,the soil loss was almost zero.For the nutrient loss, the loss of organic mater and the total loss of N, P, K were 50.049 kg·hm-2 and 31.508 kg·hm-2 in the juvenile plantation, 6.080 kg·hm-2 and 2.096 kg·hm-2 in the middle aged plantation, and 10.784 kg·hm-2 in the pre mature plantation.In the juvenile plantation, the soil loss occurred in maximum amount during the first year when the plantation was established and decreased year by year and came to an extremely little amount 4 years after the plantation establishment.For the surface runoff, it seemed no signiflcant relation to the plantation age.In the plantation with soil derived from slate, it had stronger resistance against soil erosion.However, during the whole rotation of Chinese fir plantation in 25 years, the total loss of soil or nutrient was very little, with accumulated amount of 1530.23 m3·hm-2 of surface runoff, 1185.7 kg·hm-2 of soil loss, 56.28 kg·hm-2 of organic mater and 44.383 kg·hm-2 of N, P, and K nutrients.K lost the most among all kind of nutrient elements.It was concluded that there would be no soil degradation in the Chinese fir plantation grown and managed at the site with soil derived from slate.