石灰岩瘠薄山地不同密度侧柏林保土效益

以临朐县石灰岩山地山坡上部营造的5种侧柏林造林密度为试验材料,系统研究侧柏林枯枝落叶层蓄积量、灌草植被生物量、土壤物理性状、渗透速率、土壤侵蚀量等保土功能指标。结果表明:(1)5种密度侧柏林的枯枝落叶层蓄积量造林密度最大的枯枝落叶层蓄积量最多,造林密度最小的枯枝落叶层蓄积量最少,林下灌草植被盖度和生物量随造林密度的减小而明显增加,密度为1 667株/hm2的侧柏林枯枝落叶量、灌木生物量和草本植物生物量总和最多,其次为2 500,1 111,5 000株/hm2的,最少的为833株/hm2。枯落物腐烂分解后可改善土壤物理性状,减小土壤容重,增加土壤孔隙度,特别是增加非毛管孔隙度,促进水分下渗。(2)5种密度侧柏林与对照相比减少的土壤侵蚀量以密度为1 667株/hm2的最大,为61.466t/hm2,其次是2 500株/hm2的,为61.092t/hm2,1 111株/hm2的为58.712t/hm2,最小的是5 000株/hm2和833株/hm2的,分别为56.664,55.2t/hm2。(3)通过对5种密度侧柏林的林分郁闭度、土壤总孔隙度、土壤非毛管孔隙度、枯落物蓄积量、土壤渗透速率、灌草生物量、灌草盖度、与对照相比减少的土壤侵蚀量等因子进行方差分析,均存在显著差异,按各项保土指标得分相加得出保土效益,计算结果显示,5种密度的侧柏林保土效益大小依次排序为:1 667株/hm2>2 500株/hm2>1 111株/hm2>833株/hm2>5 000株/hm2。

Soil Conservation Benefits of Different Densities of Orientalis in Shandong Limestone Barren Mountain

In order to explore the soil conservation benefits of different densities of orientalis in Shandong limestone barren mountain,the soil conservation functions of 5 kinds of densities of orientalis are analysised in field measurement and laboratory.The results showed:(1)In the five orientalis forests of different density,the forest with the maximum planting density had the greatest amount of litter accumulation,however,the forest with the minimum planting density had the least amount of litter accumulation,understoryed shrubs and grass vegetation cover and biomass multiply with the decreased planting density,litter biomass,biomass of shrubs and herbaceous biomass with the density of 1 667 lines/hm2 orientalis were the most followed by 2 500 lines/hm2,1 111 lines/hm2,5 000 lines/hm2 and 833 lines/hm2 at last.The decomposition of litter had improved soil physical properties,reduced soil bulk density,increased soil porosity,and in particular urged the increase of non-capillary porosity,and promote water infiltration.(2)Meanwhile,it was proved that the 1 667 lines/hm2 stand controlled the biggest soil erosion amount of 61.466 t/hm2,followed by stand of 2 500 lines/hm2,1 111 lines/hm2 with the amount of 61.092 t/hm2 and 57.712 t/hm2.The 5 000 lines/hm2 and 833 lines/hm2 stand controlled the smaller amount of 56.664,55.2 t/hm2.(3)From the variance analysis of indexes,such as the canopy density,total soil porosity,soil non-capillary porosity,amount of litter layer,soil infiltration rate,shrub grass biomass of understory herbs,controlled amount of soil erosion,there were significant differences between different stands.The results showed that the soil conservation benefits of five different density types decreased in the order of 1 667 lines/hm2,2 500 lines/hm2,1 111 lines/hm2,833 lines/hm2,5 000 lines/hm2.