黄土塬区苹果园土壤水文特征及蒸散规律

发布时间：2018-06-27 08:12

本文选题：黄土塬区 + 苹果园　；参考：《中国科学院研究生院(教育部水土保持与生态环境研究中心)》2016年硕士论文

【摘要】：本研究主要以黄土塬区的苹果园为研究对象,围绕水量平衡和蒸散过程,在定点监测的基础上,分析苹果林冠层截留特征及影响因子、不同降水年型苹果园的蒸散规律、主要农林用地土壤水文特征及水量平衡闭合状态。主要研究结论如下:林冠对果园降水再分配过程具有重要影响。结果表明,苹果园成林与幼林的降水再分配过程中穿透雨量最大,冠层截留量次之,树干茎流量最小,分别占总降水量的80.4%、16.7%、2.9%;苹果园成林相对于幼林的穿透雨率低,冠层截留率高,苹果园成林有利于截获降雨,而幼林利于穿透雨的形成。不同降雨量级对林冠层的降水再分配有明显影响,随着降雨量级的增大,苹果园内穿透雨量、穿透率、树干茎流量、树干茎流率和林冠截留量均呈增大趋势,但冠层截留率随雨量级增大而逐渐减小;在同一降雨量级中,苹果园的物候特征对降水再分配过程影响显著,穿透雨率随时间呈先降低再升高的趋势,冠层截留率随时间呈现先升高再降低的趋势,在整个生长季,穿透雨率与冠层截留率呈负相关关系。苹果园在生长季内的半月尺度蒸散变化规律呈明显的双峰曲线,第一峰值出现在7月后半月或者8月前半月,第二峰值出现在9月前半月。2012㧟2014三年期间,苹果生长季内的蒸散量占降水量的比例分别为103%、104%与99%;2012年的蒸散量高出降水量12.1 mm,2013年的蒸散量高出降水量18.2 mm,2014年的蒸散量小于降水量1.2 mm。苹果园蒸散在生长季内的变异系数为1.0左右,脉动程度较大。在属于典型雨养农业区的长武塬区,自然降水是苹果经济林生态系统蒸散耗水的主要水分来源,降水量的多少直接影响着苹果的质量与数量。在枯水年(2012年)和偏枯的平水年(2013年),蒸散量大于降水量,即降水输入不能满足果园蒸散需水,土壤贮水表现为亏缺状态;在平水年(2014年),当年降水量可满足果园蒸散耗水的要求。同时,黄土塬区苹果园土壤水及蒸散对降雨产生快速水文响应机制,降落到林地的雨水迅速以土壤蒸发,植被蒸腾等形式进行水分输出。对黄土塬区主要农林用地的土壤水分变化特征及其干化现状进行分析。结果表明:0㧟600 cm土壤贮水量表现为9龄果园玉米地小麦地19龄果园,均值分别为186.5 cm、183.6 cm、158.6 cm与132.8 cm,除9龄果园与玉米地间差异性不显著(P0.05)外,其他农林用地土壤贮水量两两比较均呈显著性差异(P0.05);四样地浅层(0㧟200 cm)土壤含水量波动程度为中等变异(10%CV100%),深层土壤含水量稳定性较高,为弱变异(CV10%);19龄果园的土壤水分消耗深度为500 cm,9龄果园、玉米地与小麦地均为300 cm,19龄果园的雨水补给深度为250 cm,而9龄果园、玉米地与小麦地均大于600 cm;19龄苹果园土壤干化最严重,0㧟200 cm土壤干化程度呈季节性变化,200㧟250cm、250㧟320 cm土层分别为严重干燥化与强烈干燥化,320㧟600 cm呈极度干燥化,形成永久性土壤干层;其次为小麦地,0㧟100 cm产生临时性干层,250㧟300 cm发生强烈干燥化;玉米地与9龄果园干化程度较轻,在水分补给不足情况下,只在土壤浅层产生临时性土壤干层。水量平衡是描述生态系统功能和特征的重要指标之一。通过对苹果园成林和幼林水量平衡的综合分析,发现水量平衡闭合情况较好;但在降水量较小或者很大时,忽略项及试验操作误差会使研究果园系统的水量平衡闭合状态相对较差。在试验期间,蒸散贡献量由小到大依次为冠层截留,棵间土壤蒸发和果树蒸腾水分蒸散,9龄和19龄果园中该三组分与蒸散量的百分比值分别为10.1%、34.8%、55.1%和8.1%、30.3%、61.6%;10龄果园和20龄果园中该三组分与蒸散量的百分比值分别为7.9%、27.0%、65.1%和12.9%、25.3%、61.8%;同时发现幼龄果园土壤蒸发量大于成林土壤蒸发,而成林果树蒸腾作用却大于幼林果树蒸腾;且土壤蒸发量及果树蒸腾量在观测期内均出现先增大后降低的趋势,土壤蒸发量6月份出现最大值,植被蒸腾最大值出现在7月,该变化规律与环境及果树生长状态关系密切。
[Abstract]:This study focuses on the apple orchard in the loess tableland area. On the basis of the water balance and evapotranspiration process, the characteristics of the canopy interception and the influence factors of the apple canopy are analyzed on the basis of fixed-point monitoring. The evapotranspiration rules of different annual apple orchard, the main characteristics of soil hydrology and the closed state of water balance in the main agroforestry are the main conclusions. The results show that the rainfall redistribution process of the orchard has an important influence. The results show that the rainfall redistribution process of the apple orchard and the young forest is the most penetrating rain redistribution process, the canopy interception is the second, the stem stem flow is the smallest, which accounts for 80.4%, 16.7%, 2.9% of the total precipitation, and the penetration rate of the apple orchard for young forest is low and the canopy interception rate is high. The orchard adult forest was beneficial to intercept the rainfall, and the young forest was conducive to the formation of the rain. The different rainfall magnitude had an obvious influence on the precipitation redistribution of the canopy layer. With the increase of the rainfall magnitude, the penetration rate, the penetration rate, the stem flow rate, the stem stem flow rate and the canopy interception in the apple orchard were all increasing, but the canopy interception rate increased with the rainfall magnitude. In the same rainfall magnitude, the phenological characteristics of the apple orchard have a significant influence on the precipitation redistribution process, and the penetration rate is first decreasing and then rising. The canopy interception rate increases first and then decreases with time. In the whole growing season, the penetration rain rate is negatively related to the canopy interception rate. The apple orchard is growing in the growth season. The variation of the transpiration in the half of the season showed a clear Shuangfeng curve. The first peak appeared in the latter half of July or the first half of August. The second peak appeared in the first half of September. During the first half of September, the proportion of the evapotranspiration in the growing season of Apple was 103%, 104% and 99%, respectively, and the evapotranspiration in 2012 was 12.1 mm, 2013 of the precipitation. The annual evapotranspiration was 18.2 mm, and the evapotranspiration was less than 1.2 mm. in 2014. The variation coefficient of the evapotranspiration of apple orchard in the growing season was about 1 and the degree of pulsation was larger. It affects the quality and quantity of the apple. In the dry year (2012) and the flat water year (2013), the evapotranspiration is greater than the precipitation, that is, the input of the precipitation can not meet the evapotranspiration of the orchard, and the soil water storage is deficient. In the year of flat water (2014), the precipitation can meet the requirement of the evapotranspiration of the orchard. The soil water and evapotranspiration produced a rapid hydrological response mechanism, and the rain fell to the woodland quickly by soil evaporation, vegetation transpiration and other forms of water output. The characteristics of soil moisture change and the present dry status of the main agricultural and forest land in the Loess Tableland were analyzed. The results showed that the 0? 600 cm soil water storage capacity was represented by the 9 year old orchard corn land The average value of 19 years old orchard in wheat field was 186.5 cm, 183.6 cm, 158.6 cm and 132.8 cm respectively. Except for 9 years old orchard and corn field, the soil moisture content 22 of other agroforestry was significantly different (P0.05), and the fluctuation degree of soil water content in the shallow layer of four samples (0? 200 cm) was moderate variation (10%CV100%) and deep soil water content. The soil moisture consumption depth of the 19 year old orchard is 500 cm, the 9 year old orchard, the corn land and the wheat land are 300 cm, the 19 year old orchard is 250 cm, and the 9 year orchard, the corn land and the wheat land are more than 600 cm, the 19 age apple orchard is the most serious soil dry, 0? 200 cm soil drying degree is seasonal. Changes, 200? 250cm, 250? 320 cm soil layers were severe drying and dryness, 320? 600 cm were extremely dry, formed permanent soil dry layer, followed by wheat land, 0? 100 cm to produce temporary dry layer, 250? 300 cm dryness; corn and 9 years orchard less dry, under the condition of insufficient water supply, only in soil under the condition of water supply The water balance is one of the most important indexes to describe the function and characteristics of the ecosystem in the shallow layer. Through the comprehensive analysis of the water balance of the apple orchard and the young forest, it is found that the balance of water balance is better, but when the precipitation is small or large, the neglect and the experimental error will make the study of the orchard system water. During the experiment, the contribution of the evapotranspiration from small to large was canopy interception, soil evaporation and fruit tree transpiration water evapotranspiration, and the percentage ratio of three components to evapotranspiration in 9 and 19 years old were 10.1%, 34.8%, 55.1% and 8.1%, 30.3%, 61.6%, and the three component and steam evapotranspiration in the 10 years orchard and the 20 age orchard. The percentage of dispersion is 7.9%, 27%, 65.1% and 12.9%, 25.3%, 61.8%, and the evaporation of the soil in the young orchard is greater than that of the forest soil, but the transpiration of the fruit tree is greater than that of the young fruit tree, and the soil evaporation and the transpiration of the fruit tree all increase first and then decrease in the observation period, and the amount of soil evaporation is released in June. The maximum value of vegetation transpiration occurred in July, which is closely related to the environment and the growth status of fruit trees.
【学位授予单位】：中国科学院研究生院(教育部水土保持与生态环境研究中心)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S661.1;S152.7

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