三峡库区不同生境下桑树林地土壤结构稳定性与持水性能

Soil Stability and Water-retention Properties of Different Mulberry Habitats in the Three Gorges Reservoir Area,China

为保证桑树在三峡库区困难立地条件下的正常生长,对该区砾石土、粗骨土、砾质土和扰动土4种生境土壤结构稳定性与持水性能进行诊断,并探讨了各种生境障碍因素的改良途径。结果表明:(1)不同生境土壤物理性质差异显著(p<0.05),土壤容重表现为粗骨土生境(1.30g/cm3)>砾石土生境(1.23g/cm3)>砾质土生境(1.12g/cm3)>扰动土生境(1.08g/cm3),砂粒含量为粗骨土生境>砾石土生境>砾质土生境>扰动土生境。(2)不同生境土壤抵御季节性干旱能力差异较大,总库容表现为砾石土生境(97.185mm)>砾质土生境(81.139mm)>扰动土生境(66.958mm)>粗骨土生境(47.353mm);而最大有效库容则为砾石土生境(54.140mm)>砾质土生境(47.552 mm)>粗骨土生境(36.399 mm)>扰动土生境(11.705mm),砾石土生境最好,扰动土最差。(3)不同生境土壤稳定性指数(ASI)表现为粗骨土生境(4.57)>砾石土生境(2.44)>砾质土生境(2.36)>扰动土生境(2.31),土壤稳定性与土壤砂粒呈显著或极显著正相关,与粉粒和粘粒呈显著负相关,与土壤孔隙状况相关性不显著。(4)桑树在不同生境的土壤障碍因素差异明显,在粗骨土生境可通过土壤改良剂和菌根接种调整土壤透水性能,在扰动土生境可通过施加保水剂改善土壤有效库容,而在砾石土和砾质土生境可通过种植固氮植物、绿肥改善土壤养分条件。

To ensure the continual growth of mulberry at inferior sites in the area of the Three Gorges Reservoir area,an analysis of soil structure stability and water-retention properties was conducted in 4habitats defined as having stony,skeleton,gravelly and disturbed soils in this paper.Furthermore,the various soil factors acting as obstacles and the ways to improve habitats were discussed.The results showed that：（1）Significant differences（p〈0.05）were found in soil physical properties at the different habitats,and the order of soil bulk density was skeleton soil（1.30g/cm3）〉stony soil（1.23g/cm3）〉gravelly soil（1.12g/cm3）〉disturbed soil（1.08g/cm3）;The sand grain content varied in the same order;（2）Resistance to seasonal drought was greatly different among these habitats,and soil total storage capacity was in the order of stony soil（97.185mm）〉gravelly soil（81.139mm）〉disturbed soil（66.958mm）〉skeleton soil（47.353mm）.Moreover,the maximum available capacity was stony soil（54.140mm）〉gravelly soil（47.552mm）〉skeleton soil（36.399mm）〉disturbed soil（11.705mm）;（3）The soil anti-erodibility index（ASI）for different habitats was in the order of skeleton soil（4.57）〉stony soil（2.44）〉gravelly soil（2.36）〉disturbed soil（2.31）.Correlation analysis indicated that soil stability was significantly or highly significant positively correlated with sand content,was highly significantly negatively correlated with powder and clay content,and was not significant correlated with soil porosity;（4）The soil factors considered as obstacles for mulberry were different in differenthabitats;soil amendments could be used to increase the soil permeability in gravelly soil habitats,water-retaining agents could be added to improve the soil available capacity in disturbed soil habitats,and nitrogen-fixing plants and green manure could be planted/added to increase soil nutrients in stony and gravelly soil habitats.