六盘山叠叠沟小流域草本地上生物量的空间变化及其与环境因子的关系

Spatial Variation of Above-ground Biomass of Grasses and its Relation with Environmental Factors in the Small Watershed of Diediegou of Liupan Mountains

在宁夏六盘山叠叠沟小流域研究了坡面草地的地上生物量空间分布规律及其与环境因子的关系。研究表明:从坡向上看,草本生物量的大小为:半阳坡(3555.47kg/hm2)>半阴坡(2545.85kg/hm2)>阳坡(2043.44kg/hm2);从坡位上看,不同坡面有所差异,半阳坡草本生物量随坡位升高呈现增加趋势,半阴坡和阳坡呈现出先增后减趋势。草本生物量与0～20cm土层的土壤容重呈负相关;与土壤含水量呈正相关。草本生物量的方差分析表明:在坡向上,半阴坡与阳坡和半阳坡表现为差异不显著,但阳坡和半阳坡之间有显著差异。在坡位上,半阴坡在中坡的草本生物量与下坡和上坡处表现为极显著差异,分别是其1.45和1.85倍;阳坡在上坡的草本生物量与中坡和下坡处分别表现为极显著和显著差异,中坡处分别是下坡和上坡处的1.36和2.29倍,下坡处是上坡处的1.68倍;半阳坡三个坡位的草本生物量差异不显著。

This paper studied the spatial variation of above-ground biomass of grasses and its relationship withe nvironmental factors in the small watershed of Diediegou in Liupan Mountains.The result indicated that,therei s a slope aspect difference for the grass biomass in the order of semi-sunny slope（3555.47 kg/hm 2）〉s emi-shady slope（2545.85 kg/hm 2）〉sunny slope（2043.44 kg/hm 2）.The biomass difference among slopep ositions varies with slope aspects：on the semi-sunny slope,the grass biomass increased gradually with risinge levation;on the semi-shady slope and sunny-slope,the grass biomass firstly increased and then decreasedw ith rising elevation.The biomass is negative related with the soil bulk density of the soil layer of 0-20cm,andp ositive related with soil water content.The variance analysis of grass biomass showed no significant differencef or the biomass on semi-shady slope compared with those on sunny slope and semi-sunny slope,but asignificant difference between the sunny slope and semi-sunny slop.The biomass at middle-slope position ons emi-shady slope has an extremely significant difference to those at the positions of upper-slope andd own-slope,it is 1.45 and 1.85 times higher;on the sunny slope,the biomass at upper-slope has an extremelys ignificant difference to that at middle-slop and a significant difference to that at down-slop respectively,theb iomass ratio at middle-slope position to down-slope and upper-slope is 1.36 and 2.29 respectively,and ther atio between down-slope to upper-slope position is 1.68;the biomass on semi-sunny slope has no significantd ifference among slope positions.