流动沙丘造林对土壤物理组分有机碳分配的影响

Allocation of Soil Organic Carbon in Physical Fractions as Affected by Plantation in Mobile Sand Dune

以科尔沁沙地为研究区域,测定分析了流动沙丘栽植22a的樟子松林和24a的小叶锦鸡儿灌木林对土壤物理组分有机碳分配的影响。结果表明,(1)流动沙丘造林后土壤粗砂、极细砂和黏粉粒含量增加,细砂含量减少,土壤容重降低。(2)流动沙丘栽植樟子松和小叶锦鸡儿林后,全土有机碳储量分别增加357和514g/m2,增幅为729%和1 050%。(3)流动沙丘、樟子松和小叶锦鸡儿林地土壤轻组质量分别为0.08%,1.24%和1.14%,轻组碳储量分别为9.7,182.5和185.9g/m2,占其全土碳储量的比例依次为20%,45%和33%。(4)土壤有机碳在不同粒级土壤中的分配状况为,流动沙丘:细砂>粗砂>极细砂>黏粉粒;樟子松林地:粗砂>细砂>极细砂>黏粉粒;小叶锦鸡儿林地:粗砂>极细砂>细砂>黏粉粒。(5)流动沙丘造林后,轻组有机碳储量的变化比总有机碳的变化更为明显,粗砂组分中非保护性有机质的增加是引起土壤总有机碳变化的主要原因。

Allocation of soil organic carbon in physical fractions was measured in mobile sand dune,and stabilized sand dune using Pinus sylvestris var.Mongolica（22 year forest land） and Caragana microphylla（24 year shrub land） in Horqin sandy land.Results show that（1） the contents of coarse sand,very fine sand and clay＋silt,and electric conductivity increased while fine sand content and soil bulk density decreased in woodland,compared with mobile sand dune,（2） the whole SOC storage increased by 729% with an increment of 357 g/m2 in forest land,and by 1 050% with an increment 514 g/m2 in shrub land,（3） dry organic matters in light fractions account for 0.08%,1.24% and 1.14% of the total soil weights,while carbon storages in light fractions are 9.7,182.5 and 185.9 g/m2,accounting for 20%,45% and 33% of whole SOCs in the mobile sand dune,forest land,and shrub land,respectively,（4） the allocations of SOC in particle-size fractions were in orders as fine sandcoarse sandvery fine sandclay＋silt for the mobile sand dune,coarse sandfine sandvery fine sandclay＋silt for the forest land,and coarse sandvery fine sandfine sandclay＋silt for the shrub land,and（5） the variations of light fraction carbon were more sensitive than the whole SOC after sand dune stabilization.Also,the increase of unprotected organic matter within coarse sand fraction played an important role in the change of whole SOC.