三峡库区消落带2种树木林下土壤的物理性质比较

摘要

[目的]研究不同树种对三峡库区消落带土壤物理性质的影响,为三峡库区消落带植被恢复与重建提供科学依据.[方法]以重庆市主城区消落带植被恢复治理示范区石门段2个树种(南川柳纯林和枫杨纯林)林下土壤为研究对象,以相邻荒地土壤为对照,对3月(消落带出露期)至7月(消落带旱季)的土壤体积质量、土壤孔隙度、土壤持水量等物理性质进行比较.[结果]3月,枫杨林下土壤物理性质与荒地土壤差异不大,3个土层平均土壤总孔隙度(23.05％)、田间持水量(69.51 g/kg)甚至略逊于荒地土壤(27.88％和86.24 g/kg);7月,枫杨林下土壤物理性质明显优于荒地土壤.3月,南川柳林下土壤物理性质优于枫杨林下土壤;7月,枫杨林下土壤物理性质明显优于南川柳林下土壤.与3月相比,7月南川柳土壤物理性质指标均出现小幅下降,但变化不显著;枫杨林下土壤由于毛管孔隙显著增加(3个土层毛管孔隙度平均值由18.86％增加至41.20％),土壤物理性质指标均显著提高;荒地土壤物理性质未出现显著变化.[结论]2种三峡库区消落带适生树种的林下土壤物理性质存在明显差异,但均能对消落带土壤物理性质起到保护和改善作用.%[Objective] This study investigated the influence of different trees on soil physical properties in hydro-fluctuation belt of the Three Gorges Reservoir area to provide scientific basis for vegetation restoration and reconstruction in this area.[Method] Soil under two kinds of trees (Salix rosthornii Seemen and Pterocarya stenoptera) in hydro-fluctuation belt vegetation restoration management demonstration area in Chongqing was studied using adjacent waste land as control.Soil physical properties (soil bulk density,soil porosity,and soil water retention) were compared between March (exposing period) and July (dry season).[Result] In March,physical properties of P.stenoptera soil had little difference with those of waste land.The average soil total porosity (23.05％) and field capacity (69.51 g/kg) of 3 soil layers were slightly less than those of waste land (27.88％ and 86.24 g/kg).In July,physical properties of P.stenoptera soil were significantly better than those of waste land.In March,physical properties of S.rosthornii Seemen soil were significantly better than those of P.stenoptera soil.In July,physical properties of P.stenoptera soil were significantly better than those of S.rosthornii Seemen soil.Compared with March,physical properties of S.rosthornii Seemen soil decreased slightly in July while physical properties of P.stenoptera soil improved significantly due to increase of capillary pore (average capillary porosity of 3 soil layers increased from 18.86％ to 41.20％).There were no significant changes of physical properties in waste land.[Conclusion] Soil properties under these 2 kinds of optimum trees in hydro-fluctuation belt of the Three Gorges Reservoir area were significantly different,but both can play a role in protection and improvement of soil physical properties.