杉木闽粤栲异龄复层林的土壤肥力及其涵养水源功能

Soil Fertility and Water Conservation of Different-aged Compound Storied Castanopsis fissa and Cunninghamia lanceolata Plantations

以福建省沙县高砂林场的重点生态区位杉木林为研究对象,研究了450、600、750、900株·hm^(-2)4个间伐保留密度下栽植闽粤栲,各处理林分的土壤物理化学性质、林分持水量及涵养水源功能。结果表明:与套种前和对照杉木纯林相比,异龄复层林土壤深度(h)0<h≤20 cm土层,土壤密度分别降低了10.15%和9.52%;粒径(D)D>0.25 mm的水稳性团聚体含量分别提高了19.03%和12.69%;结构体破坏率分别下降了21.52%和11.61%;总孔隙度分别提高了6.57%和4.95%。与套种前相比,0<h≤20 cm土层的全磷、全氮、有机质质量分数分别提高39.02%、26.96%和29.33%,速效钾、速效磷和水解氮质量分数分别提高了24.32%、38.09%和14.37%。与对照杉木纯林相比,林分总持水量提高19.38%;地表径流系数下降23.21%。20 cm<h≤40 cm土层也呈现同样规律。方差分析显示,各保留密度处理均可显著改善土壤的物理化学性质及其涵养水源功能,以600株·hm^(-2)保留密度套种的效果最优。

With Cunninghamia lanceolata mixed with Castanopsis fissa under densities of 450,600,750 and 900 stem·hm^（-2） after thinning located at the key ecological niches in Gaosha Forest Farm of Shaxian County. The soil physical and chemical properties,water-holding capacity,and water conservation function were measured. The soil density was decreased,respectively,by 10.15% and 9.52% in 0-20 cm layer of the soil in different-aged compound storied C. fissa and C. lanceolata plantations compared with that before inter-cropped and pure C. lanceolata control. Similarly,the content of water-stable aggregates particle size（ D） D0.25 mm increased by 19.03% and 12.69%,while structure destruction rate decreased by21.52% and 11.61%,respectively. Meanwhile,total porosity was increased by 6.57% and 4.95%. Compared with plantations before inter-cropped,contents of total P,N,and organic matter in soil of 0-20 cm layer were increased by 39.02%,26.96%,and 29.33%,and those of rapid K,P,and hydrolysable nitrogen increased by 24.32%,38.09%,and 14.37%,respectively. Compared to the pure C. lanceolata plantation,the total water holding quantity was enhanced by 19.8%,the while surface runoff coefficient was decreased by 23.21% in the uneven aged mixture,and the soil of 20-40 cm layer was also present with the same trend. By the analysis of variance,each retention density can significantly improve soil properties and water conservation function,among which the optional density was 600 tree·hm^（-2）.