【作者】 马维伟；

【导师】 王辉；

【作者基本信息】 甘肃农业大学 ， 水土保持与荒漠化防治， 2008， 硕士

【摘要】 人工林在木材生产,环境保护和景观建设中具有重要的功能和作用,而且将成为森林生态系统中愈来愈重要的组成部分。兰州南北两山人工林生态系统是兰州市城市生态系统的重要组成部分,对兰州市城市生态环境有着举足轻重的影响。研究分析兰州南北两山人工林地的土壤水分物理特征,对揭示南北两山森林与土壤的互动作用机理、森林对环境的保护作用具有重要的理论意义和应用价值。本文以兰州北山侧柏人工林为例,对其土壤水分性质、土壤物理性质、土壤渗透特征进行了研究分析,得到以下一些初步结论:(1)5种立地类型(阳坡、半阳坡、阴坡、半阴坡、梁峁台)条件下,侧柏林地在同一时期内土壤水分垂直变化规律基本一致,自上而下呈现出不稳定的变化特征。除梁峁台外,其他立地类型的水分变异系数基本呈现自上而下逐渐减小态势,不同立地类型土壤水分变异系数大小依次为:半阴坡>梁峁台>半阳坡>阴坡>阳坡。(2)不同林龄的侧柏人工林的土壤最大蓄水量没有差异,而涵养水源量存在着明显的差异。不同林龄的侧柏林地土壤涵养水源量(0～30cm)都显著高于荒地,其中,13a、10a、7a、4a生侧柏林地水源涵养量分别比荒地高201、268、251和208t/hm2,说明侧柏林地有较高的水源涵养功能。(3)土壤最大持水量、毛管持水量、田间持水量和最佳含水率随林龄的增大而增加,其大小均是13a生侧柏林地最大,无造林荒山地最小;0～30cm层土壤水分有效性在4a生林地表现为中效水,其他林地大都为难效水;与无造林荒山相比,不同造林年限的侧柏人工林地土壤持水量均有一定程度增加。说明侧柏人工林能够改善土壤表层水分状况。(4)不同林龄侧柏林地土壤容重都表现为随林龄的增大而减小,随土层深度的增加而增大;而不同林龄侧柏林地的土壤总孔隙度和非毛管孔隙度随林龄的增大而增大,随土层深度的增加而减小;林地土壤的总孔隙度都比荒地高,表明林地土壤的物理性状和结构要优于无林地。(5)不同林龄侧柏林地土壤渗透性能存在很大差别,具体表现为栽植年限越长,渗透性能越好。运用霍顿公式f= f 0+﹙f c- f 0﹚×e- kt进行曲线拟合,相关系数R2在0.64～0.95之间。(6)侧柏林地的土壤渗透系数与容重的回归方程为:y1=1.381- 0.609x1(R=-0.790);侧柏林地的土壤渗透系数与非毛管孔隙度的回归方程为:y2=3.664+5.096 x2(R=0.68)。(7)不同灌溉方式的侧柏林地土壤渗透性能存在显著差异,林地0～20㎝层的渗透性能好于20～40㎝,不同灌溉方式林地渗透性能具体表现为:喷灌林地>漫灌林地>弃灌林地>荒坡地,不同灌溉方式的林地土壤入渗过程符合对数曲线,对方程进行数学运算所求的累积入渗量和实测入渗量基本相符。(8)不同林龄林地间渗透特征存在差异,但林地的渗透能力都强于荒坡地。如:土壤的稳渗速率林地(0.43mm/min)﹥荒坡地(0.09mm/min),平均入渗率也是林地(0.53mm/min)﹥荒坡地(0.19mm/min)。更多还原

【Abstract】 The artificial forest plays an important role in wood production, environmental protection and landscape design, and will become more and more important in forest ecosystems. Ar- tificial forest ecosystem of Lanhzou South-north Hills is an important component of Lanzhou urban ecosystem,it has decisive influence on Lanzhou urban ecological environment.Study on soil water physical properties of the artificial forest, which can reveal interaction mech- anism between forest and soil ,can clarify forest protective function to environment, so it has essentially theoretical and practical value. Based on the systematic research on forest stan- ds characteristics and the space distribution of soil hydro-physical property, soil infiltration characteristics,the main results are as follows:(1)Soil water vertical variation tendency of five site types was basically identical at the same period and showed an unstable tendency from top to bottom. Except liang, mao and tai, the variation coefficient of other site types basically showed a tendency to reduce from top to bottom. The variation coefficient was as the following: semi-shady slope>liang and mao and tai> semi-sunny slope> shady slope> sunny slope.(2)The maximum moisture capacity of Platycladus orientalis forestland had no distinctive difference in different stand ages,but the water conservation content varied significantly.The water conservation content of 4 different afforestation ages (4-year-old,7-year-old,10-year- old and 13-year-old) had been increased 201、268、251 and 208t·hm-2 than that of slope wasteland separately. It showed that Platycladus orientalis plantations have the high fun- ction of conservation water.(3)The maximal holding of water in soil, capillary water capacity, field capacity and optimum water rate increased with tree ages. In these indexes,those of 13-year-stand age were the most and those of wasteland were the least; soil water availability of forestland(0～30cm) was moderate 4a,and was irreadly available for other forestland; Compared with wasted land, soil moisture content of different young plantation stages increased to some degree. These findings showed that Platycladus orientalis plantations could improve soil surface water condition.(4)The soil bulk density of the Platycladus orientals plantation of different ages were decreased with tree ages, but it increased with the depth of soil layer incresed. However, the no-capillary and total porosity increased as tree ages, and decreased with the depth of soil layer increased. The total porosity of forestland was higher than the wasted land. The results showed that the structures and physical characters of forestland better than that of the wasted land.(5)There were obvious permeability differences in different planting forestland. It displayed as: the better the soil percolation capacity, the longer the forest was planted. Soil permeability process of forest land followed Horton equation f= f 0+﹙f c- f 0﹚×e- kt, correlation coefficient 0.64～0.95.(6) Congress equation of the infiltration coefficient and soil bulk density of Chinese pine stand was: y1=1.381-0.609x1,R=-0.790;Congress equation of the infiltration coefficient and no-capillary of Chinese pine stand was : y2=3.664+5.096x2,R= 0.68.(7) There were obvious permeability differences in different irrigation patterns, and the soil percolation capacity of the upper soil layer(0～20㎝)was better than the under layer(20～40㎝). The soil percolation capacity in different irrigation patterns was as following: Sprinkler Irrigation﹥flood irrigation﹥abandoned irrigation﹥bare-slope. Soil permeability process conformed to logarithm function law. It was proved by equation which the simulation calculation result was basically same as that obtained by actual measuring.(8)There were differences in soil permeability characteristics of different planting forestland, but soil permeability characteristics of forestland were better than bare-slope. For example, the final infiltration rate of forestland(0.43mm·min-1)﹥bare-slope(0.09mm·min-1), the average rate of forestland(0.53 mm·min-1)﹥(0.19 mm·min-1).更多还原