梭梭林下土壤结皮发育对降水入渗动态的影响

研究梭梭林下土壤结皮发育对降水入渗、土壤水分动态的影响，旨在掌握梭梭林地管理和促进林下植被发育的关键技术。结果表明:1）土壤结皮发育对各层土壤含水率的变化具有显著影响（P<0.05），0~0.5 cm土层土壤含水率的变化随土壤结皮发育逐渐增大，而其余土层逐渐减小。随土壤深度增加，无结皮沙地（NSC）和物理结皮沙地(PSC)土壤含水率先增加后减小，生物结皮沙地(BSC)逐渐减小。2）土壤结皮发育对林下土壤水分动态产生显著影响（P<0.05），随着土壤结皮的发育，0~0.5 cm土层土壤水分波动幅度逐渐增强，而其余土层则逐渐减弱，表现为NSC>PSC>BSC。NSC和PSC样地水分波动频度较大，BSC样地没有明显的波动。3）高强度降水下(区间降水39 mm)，三者降水的入渗强度和入渗深度较大，而中（区间降水19 mm）、轻（区间降水8 mm）强度降水下，NSC和PSC样地产生轻微的浅层入渗，BSC样地保持在稳定的水平，表现为NSC>PSC>BSC，可知梭梭林下土壤结皮发育对降水的截留作用逐渐增强，限制了降水的入渗，但在稳定深层土壤水分和限制深层土壤蒸发方面具有积极的作用。

Effects of Soil Crust Development on Precipitation Infiltration Dynamics under Haloxylon ammodendron Plantations

Soil crust was widely developed under Haloxylon ammodendron plantations in arid desert areas,and its development had an important effect on soil hydrological cycle.This paper studied the effect of soil crust development on precipitation infiltration and soil moisture dynamics under the plantations.The objectives of this study were to master the key technologies on management of H.ammodendron plantations and to promote the development of land vegetation.The results showed that 1) soil crust development presented a significant effect on the soil moisture change (P<0.05).Soil moisture change in the crust development layer (0-0.5 cm) gradually increase with soil crust development,while it gradually decreased in the other layers.With the increase of soil depth,the change of soil moisture increased firstly and then decreased in the non-soil-crust (NSC) and physical soil crust (PSC) plots,but in the biological soil crust (BSC) plots,it showed a gradually decreasing trend.2) Soil crust development had a significant effect on soil moisture fluctuation（P<0.05）under the plantations.With the soil crust development,the fluctuation amplitude increased in the crust development layer (0-0.5 cm),while it gradually decreased in the other soil layers.The fluctuation amplitude in the soils with different crusts was in the order of NSC>PSC>BSC.The fluctuation amplitude and frequency of soil moisture were relatively higher in the NSC and PSC plots,while soil moisture had no obvious change in the BSC plots.3)Under highly intensive rainfall conditions(interval precipitation 39 mm),high the infiltration intensity and depth were found in three crust,under moderately (interval precipitation 19 mm) and lightly (interval precipitation 8 mm) intensive rainfall conditions,light infiltration in the shallow layer was found in NSC and PSC,while in BSC,it was stable,and the filtration was in the order of NSC>PSC>BSC.It was concluded that that the interception of precipitation of soil crust gradually increased with the development of the crust under H.ammodendron plantations.The crust inhabited the rain water filtration,on the other hand,curst played a positive role in stabilized soil moisture and limited moisture evaporation of deep soil layers.