干化土壤中植被生长及土壤水分特征试验研究

发布时间：2018-03-30 05:29

本文选题：干化土壤　切入点：植被　出处：《中国科学院大学(中国科学院教育部水土保持与生态环境研究中心)》2017年硕士论文

【摘要】：目前黄土丘陵人工林地的土壤干化问题严重,这种土壤现象一旦形成,便很难在短时间内得到恢复。众多学者担心,永久性干层的形成,不仅会对现存植被生长不利,而且会给后续植被的选择和生存带来很大影响。在黄土高原大规模退耕还林还草的背景下,研究干化土壤上后续植被的种植及其生长状况甚为重要。本研究在陕西省米脂县远志山红枣基地进行,通过在大田干化土壤状况下种植枣树及模拟干化土壤环境中种植早熟禾、苜蓿、柠条、刺槐等不同植被,研究干化状况下不同植被生长及土壤水分变化特征。利用定位监测获取试验区10米土层土壤水分,同时定期测量各植被生长指标及生物量,分析干化土壤中不同植被土壤水分动态变化、各植被生长状况及其水分利用效率。以期为干化土壤后续植被的建造提供理论依据,为干化环境中土壤水分管理提供借鉴。主要获得以下结果:(1)研究区土壤干化情况:研究区为23年生旱作苹果园地,耗水深度已达到1000cm,休闲4年后栽植枣树。此时伐后土壤300~500、500~700、700~1 000 cm范围土壤水分亏缺度分别为41.56%-45.93%、36.82%-41.56%、20.26%-24.32%,分别达到中度偏重亏缺、中度亏缺、轻度亏缺。模拟干化土壤的剖面土壤含水量均一,土壤平均含水率保持在7.5%左右,水分亏缺度为43.19%,整体达到中度亏缺状态。(2)模拟干化土壤中各植被土壤水分变化范围及规律不同:2014-2016年早熟禾年耗水量均小于当年降水量,土壤储水量及水分变化深度逐年增加,至2016年土壤水分增加范围为0-300cm,该层次土壤储水量较初期增加327.92mm;2014年苜蓿年耗水量(405.8mm)小于当年降水量(460.4mm),0-180cm土层土壤水分得到补充,该土层储水量较初期增加54.6mm,2015年-2016年苜蓿年耗水量均大于当年降水量,土壤储水量逐年减少,至2016年耗水范围达到0-600cm,该层次土壤储水量较初期减小126.37mm;2014年柠条年耗水量(402.93mm)小于当年降水量,0-180cm土层土壤水分得到补充,该土层储水量较初期增加57.89mm,2015年-2016年柠条年耗水量均大于当年降水量,土壤储水量逐年减少,至2016年耗水范围达到0-400cm,该层次土壤储水量较初期减小44.66mm;2014年刺槐土壤水分变化规律与苜蓿、柠条相同,0-180cm土壤储水量较初期同层次增加26.86mm,但2015年开始刺槐年耗水量均远大于当年降水量,0-1000cm范围内土壤水分急剧减少,至2016年0-1000cm范围内土壤储水量较初期减少231.2mm。(3)模拟干化土壤中早熟禾、苜蓿、柠条、刺槐等生长受当年降水量影响较大。2016年降水量远大于2015年,各植被生物量均高于2015年,其中苜蓿生长量变化最大,2016年其生物量是2015年的1.6倍;2016年各植被水分利用效率均低于2015年,其中苜蓿水分利用效率变化最大,2016年其水分利用效率是2015年的87%。2年间苜蓿水分利用效率均大于其他植被。(4)大田干化枣林生长期间主要消耗0-300cm的土壤水分,该层次土壤水分逐年减少。伐后土壤0-300cm土层平均土壤含水率为10.17%,土壤储水量为305.24mm;3龄、4龄、5龄枣林同层次平均土壤含水率分别为8.77%、6.83%、6.65%,较伐后土壤分别减少1.41%、3.34%、3.52%;土壤储水量较伐后土壤分别减少42.24mm、100.27mm、105.79mm。以当地15龄老枣林0-600cm土层范围内平均含水量为依据计算枣林有效水量,发现伐后土壤0~300 cm土层土壤可用有效水总量为149.71 mm,3龄枣林消耗可用有效水为34.97%,4龄枣林消耗可用有效水为83.04%,5龄时枣林由于缺乏有效水分只能消耗剩余有效水量的4.59%。可见大田干化枣林在4龄后即基本失去土壤水分的有效供给。(5)大田干化枣林3龄后采用节水型修剪,在干化环境中仍能保持良好生长。将干化土壤中采取节水型修剪的枣林生长状况与相同水分条件下的常规矮化修剪、正常水分条件下的常规矮化修剪枣林对比发现,大田干化枣林采用节水型修剪后,其产量及水分利用效率均高于相同水分条件下的常规修剪枣树,并且产量可达到正常水分条件下枣树的1.39倍以上,产量水分利用效率可达其1.52倍以上。
[Abstract]:The Loess Hilly plantation soil desiccation problem is serious, the phenomenon of soil once formed, it is difficult to recover in a short period of time. Many scholars worry that the permanent dry layer, not only on the existing vegetation growth has great impact on adverse selection and survival, and will give the following vegetation in the Loess Plateau of mass. Returning farmland to forest and grassland in the background, study and growth status of dry planting soil following vegetation is very important. This study was carried out in Polygala Mizhi County of Shaanxi Province mountain red dates base, by dry soil conditions in the field planting and seeding jujube Planting Simulation bluegrass, dry soil of alfalfa, Caragana, different the study of vegetation, under the condition of different vegetation growth and soil moisture variation of stem. Using location monitoring acquisition test area 10 meters of soil water, and the vegetation growth index measured regularly And analysis of dry biomass, dynamic changes of soil moisture in the soil of different vegetation, the vegetation growth and water use efficiency. In order to provide theoretical basis for the construction of dry soil following vegetation, and provide reference for the management of soil moisture and dry environment. Mainly the following results: (1) dry soil research area: the study area for 23 years in apple orchard, water consumption depth has reached 1000cm, leisure 4 years after planting jujube trees. At this time of soil 300~500500~700700~1 000 cm soil moisture deficit degree were 41.56%-45.93%, 36.82%-41.56%, 20.26%-24.32%, respectively, on moderate deficit, moderate deficit, mild water deficit. The water content of soil were simulated dry soil, the average soil water content remained at around 7.5%, the water deficit degree is 43.19%, the overall deficit reached moderate state. (2) the simulation of dry soil moisture in soil Change the scope and distribution of different bluegrass: 2014-2016 years of annual water consumption is less than that of precipitation, soil water storage and water depth change increased year by year, to 2016, soil moisture increased the range of 0-300cm, the level of soil water storage is increased at the early stage of 327.92mm; in 2014 the annual water consumption of Alfalfa (405.8mm) smaller than that of precipitation (460.4mm). 0-180cm soil water supplement, the soil water storage is increased at the early stage of 54.6mm, 2015 -2016 annual water consumption of alfalfa were higher than that of precipitation, soil water storage decreased year by year, to 2016 water consumption range reached 0-600cm, the level of soil water storage decreased compared with the initial 126.37mm in 2014; the annual water consumption of Caragana (402.93mm) less than the year precipitation the amount of 0-180cm, soil water supplement, the soil water storage is increased at the early stage of 57.89mm, 2015 -2016 annual water consumption was higher than that of Caragana precipitation, soil water storage The amount of water consumption decreased year by year to 2016 range reached 0-400cm, the level of soil water storage decreased compared with the initial 44.66mm; Caragana 2014 soil moisture variation of Robinia pseudoacacia and alfalfa, the same 0-180cm, compared with the initial soil water storage with increased levels of 26.86mm, but the beginning of 2015 annual water consumption of Robinia pseudoacacia were much larger than that of precipitation, soil moisture in the range of 0-1000cm sharply reduced to 2016 in the range of 0-1000cm soil water storage decreased compared with the initial 231.2mm. (3) simulated dry soil bluegrass, alfalfa, Caragana, locust growth by year precipitation affected.2016 annual precipitation than in 2015, the vegetation biomass was higher than that in 2015, the biggest change amount of alfalfa growth, 2016 the biomass is 1.6 times in 2015; in 2016 the vegetation water use efficiency was lower than that in 2015, the WUE was the biggest change in 2016, the water use efficiency in 2015 87%.2 years of Alfalfa water use efficiency were higher than that of other vegetation. (4) field soil water dry jujube growth during the main consumption of 0-300cm, the level of soil moisture decreased year by year. After cutting 0-300cm soil layer the average soil water content is 10.17%, the soil water storage was 305.24mm; 3 age, 4 age, 5 age of jujube with the level of the average soil water content were 8.77%, 6.83%, 6.65%, compared with the soil after cutting were reduced by 1.41%, 3.34%, 3.52%; the soil water storage of soil were reduced compared with 42.24mm, 100.27mm, 105.79mm. in the local 15 age old jujube forest in 0-600cm layer average moisture content is calculated on the basis of the effective content of jujube forest, found in after the soil 0~300 cm soil available water amount was 149.71 mm, 3 year old jujube available water consumption is 34.97%, 4 instar of jujube forest available water consumption was 83.04%, 5 at the age of jujube forest due to the lack of effective water can only consume the remaining available water The amount of 4.59%. visible in the field of effective supply of dry jujube at the age of 4 after the basic loss of soil moisture. (5) the field of dry jujube forest after 3 years using water-saving pruning, can still maintain good growth in the dry environment. The dry soil by conventional pruning dwarf jujube forest water-saving pruning with growth in the same water condition, the conventional dwarf forest contrast trim jujube found under normal water condition, the field of dry jujube forest using water-saving pruning, its yield and water use efficiency were higher than that of the same water under the condition of normal pruning and jujube, yield can be achieved under normal water condition of jujube more than 1.39 times the water use efficiency, yield up to 1.52 times more.

【学位授予单位】：中国科学院大学(中国科学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】：2017
【分类号】：S152.7

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