【作者】 易亮；

【导师】 李凯荣；

【作者基本信息】 西北农林科技大学 ， 水土保持与荒漠化防治， 2009， 硕士

【摘要】 针对黄土高原生态环境恶化以及黄土高原防护林体系经济效益低下的问题,以黄土高原沟壑区生态经济型防护林为研究对象,通过野外调查与室内分析相结合的方法,系统研究了林地的水分和养分特征,并以水分生态条件为依据,对黄土高原沟壑区生态经济型防护林进行了空间配置。研究取得以下主要结论:(1)黄土高原沟壑区不同立地类型生态经济型防护林地土壤养分层次变异程度总体表现为阴坡＞半阴坡＞半阳坡＞塬面(平地)＞阳坡。林地土壤有机质和碱解氮含量较低,速效磷、速效钾含量相对较高。经济林中仁用杏和柿树林地P肥最为缺乏,杏树林地最缺N肥,花椒林地最缺N肥和P肥,核桃林地最缺乏K肥。(2)黄土高原沟壑区生态经济型防护林地土壤水分年内季节动态可划分为生长季初土壤水分相对稳定期、生长季中土壤水分强烈消耗期、生长季中土壤水分恢复补偿期以及生长季末土壤水分缓慢蒸发期这4个阶段。土壤水分含量垂直变化划分为土壤水分弱利用层、土壤水分利用层和土壤水分调节层3个层次。(3)欠水年除了核桃林地水分供求关系协调外,其它经济林地在生长季内供水量均小于耗水量,出现不同程度的水分亏缺现象,水分供需矛盾突出。(4)生态经济型防护林地不同树种间土壤水分生态位适宜度大小表现为核桃＞侧柏＞油松＞柿树＞杏树＞刺槐＞花椒＞仁用杏。(5)根据土壤水分生态条件,提出了黄土高原沟壑区不同地貌部位的防护林和经济林树种的空间配置方案,并且依据树木胸径和林地水分营养面积关系,确定了主要造林树种的合理林分密度。更多还原

【Abstract】 To solve the problem of environment deterioration and low economic benefit for protection forest system in Loess Plateau,we systematically studied the soil moisture and nutrients for eco-economic type of protection forest in gully region of loess plateau through field investigation and laboratory analysis.Based on the soil moisture condition,we further conducted the spatial allocation.The main conclusions are as follows:1.The variance of soil nutrient in different layers on different sites were North Slope＞East Slope＞West slope＞tableland(flatland)＞South Slope.Soil organic matter and alkali-hydrolyzable nitrogen were deficient,while available phosphorus and available potassium were abundant.For different economic forest lands,phosphorus was the most deficient fertilizer for both Almond-apricot(Prunus armeniacia×sibirica)and Persimmon (Diospyros kaki L.f)lands;nitrogen took the first place of deficiency in Apricot(Armeniaca vulgaris Lam.)land,and then phosphorus and potassium;Prickly ash(Zanthoxylum bungeanum Maxim)land lacked nitrogen and phosphorus,Walnut(duglans regia L.)lacked potassium.2.The annually seasonal dynamics of soil moisture were divided into four stages: relatively stable period in the initial stage of growing season,intensive consumption period in the middle stage of growing season,recovery compensation period in the middle stage of growing season,and slowly evaporation period in the late stage of growing season.Soil water content was vertically divided into three layers:faint utilization layer,utilization layer,and adjustment layer.3.In dry year,except that walnut land water supply-demand was harmonious the whole year,the water supply was almost entirely less than water consumption spanning the growing season in other lands.As a result,there was water deficiency in these lands;the supply protruding contradicted the consumption.4.Average water niche suitability for different eco-economic forest lands declined in the order Walnut(Juglans regia L.)＞Arborvitae(Platycladus orientalis(L.)Franco)＞Chinese Pine(Pinus tabulaefoemis Carr.)＞Persimmon(Diospyros kaki L.f)＞Apricot(Armeniaca vulgaris Lam.)＞Black Locust(Robinia pseudoacacia L.)＞Prickly Ash(Zanthoxylum bungeanum Maxim)＞Almond-apricot(Prunus armeniacia×sibirica).5.According to the water ecology condition,we proposed the spatial allocation scheme for protection forest and economic forest of different geomorphologic position in loess gully region.Further more,the reasonable stand density of main afforestation species was determined according to the relationship between DBH and water nutrition area.更多还原