晋西黄土区退耕还林后土壤入渗特征及土壤质量评价

为研究晋西黄土区退耕还林后不同植被覆盖下土壤的入渗特征及土壤质量评价,采用野外双环入渗法测定土壤的入渗特征,并测定不同地类土壤的容重、孔隙度、有机质、全氮等指标,使用相关性分析研究不同类型植被覆盖下土壤的入渗性能及其与土壤理化性质的相关关系,并将各地类的土壤理化性质进行主成分分析。结果表明:(1)植被类型对于土壤渗透速率影响较大,表现为天然次生林刺槐×油松混交林刺槐纯林油松纯林灌木林地苹果园地荒草地农田(玉米地)。(2)退耕还林后,不同植被类型的土壤理化性质差异显著(P0.05),随着森林逐渐恢复,土壤容重下降,孔隙度及有机质等含量增加,土壤理化性质得以改善,入渗性能也有明显提高。土壤入渗特征与总孔隙度、非毛管孔隙度、有机质和全氮含量呈极显著正相关(P0.01),与容重呈极显著负相关(P0.01),与速效磷呈显著负相关(P0.05)。(3)综合土壤入渗性能和土壤理化性质作为土壤评价指标,晋西黄土区退耕还林后不同植被类型土壤质量从高到低依次为次生林刺槐×油松混交林刺槐纯林油松纯林灌木林地苹果园地荒草地农田。

Characteristics of Soil Infiltration and Soil Quality Evaluation After Conversion of Farmland to Forest in Loess Region of Western Shanxi Province

In order to study the soil infiltration characteristics and soil quality evaluation under different vegetation cover after returning farmland to forest in the loess region of Western Shanxi Province, the field double-ring infiltration method was developed for the determination of soil water infiltration characteristics. The soil bulk density, porosity, organic matter, and total nitrogen were studied. Correlation analysis was used to study the relationships between soil infiltration capability and the physical and chemical properties of soil. Principal component analysis was also used on the soil physical and chemical properties. The results showed that:(1) Vegetation type had a great influence on soil permeability rate, which was as follows natural secondary forest > Mixed forest of Robinia pseudoacacia and Pinus tabulaeformis > Robinia pseudoacacia forest > Pinus tabulaeformis forest > Shrub > Malus pumila > waste grassland > farmland. (2) After the conversion of farmland to forest, the soil physical and chemical properties of different types of vegetation had significant differences. With the better degree of forest restoration, the soil bulk density decreased, and the contents of porosity and organic matter increased, the soil physical and chemical properties was also gradually improved. Soil infiltration characteristics were significantly positively correlated with total porosity, non-capillary porosity, organic matter and total nitrogen content (P < 0.01), significantly negatively correlated with bulk density (P < 0.01), and significantly negatively correlated with available phosphorus (P < 0.05). With the conversion from farmland to waste grassland, shrub and arboreal forest, soil physical and chemical properties were improved and soil permeability was also gradually enhanced. (3) Soil infiltration performance and soil physical and chemical properties were used as soil evaluation indexes. The order of soil quality of different vegetation types from high to low was as follows natural secondary forest > Mixed forest of Robinia pseudoacacia and Pinus tabulaeformis > Robinia pseudoacacia forest > Pinus tabulaeformis forest> Shrub > Malus pumila > waste grassland > farmland.