摘要
在岷江上游杂谷脑河流域特殊的地理环境背景下,土壤水分成了限制林树下线树木生长和分布的关键因子,采用野外定位试验与室内试验相结合的方法,对岷江上游杂谷脑河流域具有代表性的林树下线土壤持水性及物理性质进行了研究,利用Gardner经验方程拟合出其土壤水分特征曲线,研究林树下线土壤持水性及其影响因素。结果表明:(1)典型土壤拟合参数a值大部分在20以上,同一种林地类型,土壤持水能力表现为阴坡>阳坡;同一坡向土壤持水能力为天然林阴坡>人工林;不同土层深度土壤持水能力为表层>下层(人工林阳坡除外)。(2)天然林和人工林的比水容重均表现为:阳坡>阴坡;阴坡和阳坡的比水容重在土层剖面上无明显规律。这说明土壤的供水能力受坡向影响大,植被类型、土层深度影响小。(3)岷江上游山区林地土壤以粉粒最多,黏粒最少,砂粒居中,且阳坡林地砂粒含量低于阴坡,粉粒和黏粒含量高于阴坡;阴坡林地土壤容重随海拔的升高而递增,阳坡林地土壤容重随海拔的升高而呈先增后减的规律,阴坡的土壤容重明显低于阳坡;林地土壤孔隙度结构总体阴坡优于阳坡。(4)林地土壤持水性与黏粒、非毛管孔隙度呈极显著正相关,与容重和毛管孔隙度呈显著正相关,退耕还林工程中,大量种植的经果林和生态林能有效改善土壤的质地。因此,在当地进行植被恢复过程中,首先要考虑的就是土壤水分问题,应当从高海拔交错带逐步向下进行,最终达到岷江上游干旱河谷困难地段的植被恢复可以顺利进行的目的。
Under the special geographical environment of Zagunao River Basin in the Upper Reaches of Min River,the soil moisture has become a key factor limiting the plant growth and distribution of the timberline.Field experiments and laboratory experiments were conducted to study the soil water-holding capacity and physical properties of typical forest trees in Upper Reaches of the Min River,the Gardner experience equation was utilized to plot a soil water characteristic curve,and the soil water-holding capacity and the influencing factors were investigated.The results showed that：（1）the fitted parameter a value of typical soil reached up to 20;（2）in the same type of woodland,soil water holding capacities of natural forest and plantation in the shady slopes were all better than sunny slopes;and in the same slopes,soil water holding capacities of plantations were better than those of the natural forests;the soil water holding capacities of surface soil were better than the deeper layer（except for artificial forest in the sunny slops）,which indicated that the water supply capacity of soil was affected greatly by the slope direction,and the vegetation type and soil depth have little influences;（3）silt content of the mountain forest soil of the upper reaches of the Min River forest soil was the highest,and the contents of clay size and sand contents were the least and middle,respectively;the soil sand content in shady slopes was higher than that of the sunny slope,and the silt content andclay contents were lower in sunny slope;the soil bulk density of forest increased with the increase of the altitude in the shady slope,and the soil bulk density increased first and then decreased with the increase of altitude in the sunny slope;the soil bulk density of the shady slope was significantly lower than that in sunny slope;the soil porosity structure was better than that of the sunny slope;（4）the soil water holding capacity of forest land was most significantly correlated with clay contents and non-capillary porosity and significant correlated with bulk density and capillary porosity,and the economic and ecological forests could improve the soil texture of large planting after the project of returning farmland to forest.Therefore,the soil moisture is the most important limiting factor in the process of local vegetation restoration.Vegetation restoration should be carried out step by step from the high altitude ecotone,and the purpose of vegetation restoration can be achieved ultimately in the difficult valley of the upper reaches of Min River.
作者
方露
李晓宁
唐香君
樊敏
幸艳
赵丽
FANG Lu;LI Xiaoning;TANG Xiangjun;FAN Min;XING Yan;ZHAO Li(School of Environment and Resources,Southwest University of Science and Technology,Mianyang,Sichuan 621010,China;County Project Information Center of Cangxi County Development and Reform Bureau,Guangyuan,Sichuan 628400,China)
出处
《水土保持研究》
CSCD
北大核心
2018年第5期95-102,共8页
Research of Soil and Water Conservation
基金
四川省教育厅项目“岷江上游土壤环境质量对退耕还林驱动的林树下线下移的响应”(16ZB0139)
研究生创新基金“冻融作用下川西北高寒土壤水热运移研究”(17ycx038)
本科生创新基金“岷江上游土壤质量对退耕还林驱动的林树下线下移的响应”(cx17-043)
关键词
岷江上游
林树下线
土壤水分特征曲线
比水容重
土壤物理性质
upper research of Min River
timberline
soil water characteristic curve
specific water capacity
soil physical properties
