黄土丘陵沟壑区不同退耕模式的土壤水文性质影响对比

Comparison of Soil Hydrologic Properties Under Different Conversion Patterns in the Hilly-gully Region of the Loess Plateau

为系统评价黄土丘陵沟壑区在“退耕还林(草)”工程实施后不同退耕模式下的土壤水分涵养功能,选取0-200 cm土层的蓄水量、土壤含水量分层比、土壤水吸力和土壤含水量年际变化率作为土壤层水分蓄存、渗透、保持和稳定性的表征指标,分别对比了不同退耕模式下的土壤水文性质。结果表明:(1)各退耕模式下土壤蓄水量差异显著,撂荒模式的土壤蓄水量最高,为还灌和还乔模式下的1.6,1.7倍;(2)还乔模式下表层土壤水分的渗透性最优,深层土壤水分的渗透潜力最大;(3)各退耕模式的土壤持水性差异显著,还乔模式下土壤水分的保持能力突出;(4)撂荒模式土壤水分的稳定性最佳,各模式0-200 cm内土壤水分的稳定性在30年前后出现拐点,土壤含水量的年际变化率由负转正,并在120 cm以下土层较为稳定。

In order to systemically evaluate soil water conservation function under the different conversion patterns after implementation of“The Grain For Green”program in the hilly and gully region of the Loess Plateau.This study selected 0-200 cm soil water storage,stratification ratio of soil water content,soil moisture suction,and inter-annual change rate of soil water content as the representative indicator of storage,infiltration,maintenance and stability of soil,which is to compare soil hydrologic properties separately in different patterns.The results showed that:(1)Soil water storage(SWS)under different conversion patterns was significantly different.The maximum SWS of grassland model was about 1.6 and 1.7 times of that under shrub and arbor model;(2)The arbor forest pattern had the best permeability of surface soil water and the biggest permeability potential of deep soil water;(3)Soil water retention under different conversion patterns was significantly different.The arbor forest pattern had the best soil water retention capacity;(4)The grassland pattern had the best stability of SWC,and the stability of SWC within 0-200 cm of each model had an inflection point around 30 years.The annual change rate of SWC changed from negative to positive,and the soil layer below 120 cm was more stable.