杉木细柄阿丁枫混交林涵养水源功能和土壤肥力的研究

The Water Holding Capacity and Soil Fertility in the Mixed Forest of Cunninghamia lanceolata and Altingia gracilides

对 2 5年生杉木细柄阿丁枫混交林进行研究表明 :混交林对土壤的物理性质、养分含量、酶活性和涵养水源功能均有良好的作用。混交林林分持水量为 2 2 1 2 .84 t/ hm2 ,杉木纯林为 1 84 1 .6 2 t/ hm2。混交林土壤水稳性团聚体组成、孔隙组成和水分状况均比纯林好 ;混交林土壤养分含量比纯林高 ,0～ 2 0 cm层有机质含量比纯林增加 80 .5 % ,全氮 ,全磷、水解性氮、速效磷和速效钾含量分别比纯林提高 2 8.8%、39.8%、32 .0 %、5 6 .6 %和 76 .8% ;混交林土壤酶活性比杉木纯林高 ,0～2 0 cm层转化酶、脲酶、酸性磷酸酶和过氧化氢酶活性分别比纯林增加 1 5 6 .1 %、72 .6 % .30 .0 %和 1 0 .3%。

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.), a fast-growing, evergreen coniferous tree with high yield and excellent wood quality, is one of the most important tree species for timber production in south China. Because of its high commercial value, native broad-leaved and coniferous forests are often transformed into plantations of pure Chinese fir. The total plantation area of Chinese fir in China is around 9.11 million hectares. Because the area of Chinese fir plantations has expanded rapidly, successive crops of Chinese fir have been planted on the same site. Many studies have reported a serious decline in the productivity of successive rotations of Chinese fir. Therefore, it is extremely important to prevent productivity decline in Chinese fir plantations in successive rotations. Since establishment of mixture plantation of Chinese fir and broad-leaf species is a practicable measure to prevent productivity decline, many mixture forests of Chinese fir and broad-leaf species were planted in my Farm since the past 30 years. The mixture of Chinese fir and Altingia gracilides is one of successes mixed patterns. In order to determine effect of mixture forest of Chinese fir and Altingia gracilides on water holding capacity and soil fertility improvement, four experimental plots were established in the mixture stand and pure stand of Chinese fir. Biomass and water holding capacities of stand, ground vegetation and deciduous layer were investigated by harvesting method and then physical properties, chemical properties and enzyme activities of soil were analyzed. Results from this study showed that mixture forest of Chinese fir and Altingia gracilides had good function to improve water holding capacity and soil fertility compared with pure stand of Chinese fir. The water holding capacities in mixture and pure plantation of Chinese fir were 2212.84t/hm 2 and 1841.62 t/hm 2 respectively. Soil aggregate composition, porosity and water condition in mixture forest were better than these in pure plantation. So did the soil nutrient condition and organic matter. The organic matter, total nitrogen and total phosphorus of soil in layer of 0～20cm increased by 80.5%, 28.8% and 39.8% respectively compared with pure plantation. The enzyme activities in the mixture forest were more active than in pure plantation. Invertase, urease, acid phosphatase and peroxidase activities in layer of 0～20cm in mixture forest increased by 156.1%, 72.6%, 30% and 10.3% respectively compared with pure plantation. Therefore, the mixture of Chinese fir and Altingia gracilides is a popularization mixed patterns to prevent soil fertility in south China.