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不同防护措施对土壤水盐含量和梭梭生长的影响
刘璐
学位类型硕士
导师蒋进
2016
学位授予单位中国科学院大学
学位授予地点北京
学位专业环境工程
关键词沙漠-绿洲过渡带 防护措施 土壤水分 土壤盐分 梭梭生长
摘要本文以塔克拉玛干沙漠南缘策勒绿洲-荒漠过渡带为研究区,在过渡带流动沙地种植梭梭幼苗,并采取不同防护措施(凋落物防护、固沙剂防护、生物灌丛防护、灌丛+凋落物防护及灌丛+固沙剂防护),研究不同防护措施对沙地土壤水分、土壤盐分及梭梭幼苗生长状况的影响。得出以下结论。 (1)在初春的灌水作用下,5月各样地土壤含水率达到最高,1m深土体平均含水率均在11%左右。随着时间的推移各样地土壤含水率均有不同程度的降低。前期5-7月份土壤含水率下降速率较快,后期7-10月份下降速率趋于平缓。不同防护措施对沙地土壤水分含量具有明显影响。其中凋落物防护、固沙剂防护下土壤水分状况较好,特别是表层0-30cm土壤含水率明显高于裸沙地,而生物灌丛区内各防护措施下土壤水分含量低于裸沙地。到试验末期10月份凋落物防护下1m深土体平均含水率最大为2.9%,固沙剂防护次之为2.45%,而其余各防护措施下1m深土体含水率均在1.6%左右。 (2)从空间尺度看,表层土壤水分受外界环境因素影响波动变化较大,特别是研究区强烈的蒸发作用,而深层土壤水分含量相对比较稳定。在初春灌水后各层土壤水分含量较为均匀,随时间的推移土壤水分逐渐向深层过渡,到10月各样地土壤水分主要都集中在60-100cm土层,其中凋落物防护下60-100cm土层平均土壤含水率为6.04%,固沙剂防护为4.47%,其余各防护措施下该层平均土壤含水率均在2%-3%之间。 (3)在绿洲-荒漠过渡带流动沙地,初春采用滴灌一次性供水135L·m-2对土壤盐分分布产生一定的影响。灌水后各防护措施下0-60cm土层土壤电导率值较小,各层土壤电导率值均在0.7ms/cm左右。60cm土层以下土壤电导率值急剧增大,70-100cm土壤电导率值远远高于0-70cm土层。到试验末期10月份0-20cm土壤盐分含量增幅较大。其中裸沙地表层0-10cm土壤电导率值为2.61ms/cm,分别是凋落物防护和固沙剂防护的3.2倍和2.5倍。生物灌丛区内各防护措施0-10cm土壤电导率值均在1.5ms/cm左右。土壤有机质含量表现为表层0-30c各 防护措施均高于裸沙地,其中凋落物防护下该层土壤有机质平均值为对照的1.65倍。土壤pH值表现为:固沙剂防护下表层0-30cm和30-60cm土层均显著低于裸沙地。凋落物防护、灌丛+固沙剂防护仅在表层0-30cm显著低于裸沙地。 (4)绿洲-荒漠过渡带在初春采用滴灌一次性供水135L·m-2,可以保证栽植梭梭苗木当年的生长需求。相比较于农田防护林每年4-9月每月灌溉一次的灌溉制度,这不仅节省了大量水资源,同时完善了农田防护林搭配荒漠灌木林的防护体系,提高了防护林对绿洲农田的防护作用。其中凋落物、固沙剂防护下梭梭苗木的株高、冠幅和基径最大,分别高于对照17.8cm、44.1dm2、4.5mm和10.2cm、25.5dm2、4.14mm。种植梭梭苗木的株高、冠幅、基径和新枝长度的最大生长速率均出现在6-8月,到9月份梭梭苗木生长速率减缓,其中冠幅和新枝长度甚至出现负增长。生物灌丛防护和综合防护措施下梭梭苗木冠幅与基径均低于对照。
其他摘要In present study, field experiments were carried out in Cele desert-oasis ecotone in the south edge of Taklimakan Desert.Through transplant the seeding of Haloxylon ammodendron and take different protection (litter shield,fixing agent shield,biological protect,composite protect) on the mobile sandy land of oasis-desert ecotone, studying the effect of different Protection Treatment on the Soil Moisture and Salt and Haloxylon ammodendron Growth,drawing the following conclusions. (1)Different protection treatment had obvious effect on sandy soil moisture content.The moisture content of surface 0-30cm soil was increased under litter shield and fixing agent shield. But this difference gradually disappeared with the increase of soil depth.The soil moisture content is low under biological protect and composite protect. With the irrigation in the early spring, the soil moisture content of May was the highest (about 10%-11%). The soil water content of different protection decreased in different degrees over time. The decline in soil moisture rate is greater from May to July, and it tends to be gentle from July to October.In the end of the experiment(October), the 1m soil moisture content of the litter shield was the maximum,which has reached 2.9%.The fixing agent shield 1m soil moisture content has reached 2.45%.While the biological protect and composite protect both in about 1.6%. (2)From the spatial scale, the environment factors have a greater influence on surface soil moisture, in particular, the strong evaporation of the study area. The surface soil moisture fluctuation range is large, and it decreases with the increase of soil depth.The soil moisture content of each layer was more evenly after the irrigation in the early spring. As time passed, the soil moisture gradually transits to deeper soils, and each sample plots soil moisture mainly concentrated in the 60-100cm soil layer by October. The soil moisture in this layer under different protection treatment in descending order is: litter shield plot 6.04%, fixing agent shield 4.47%, biological protect plot and composite protect plot both in 2%-3%. (3)On the mobile sandy land of desert-oasis ecotone,the one-time irrigation about 135L·m-2 in early spring has a certain effect on soil salt distribution.The soil electrical conductivity of the soil in 0-60cm is lower after the irrigation, which was about 0.7ms/cm in each layer. Below 60cm soil, the soil electrical conductivity increased rapidly, and its value of 70-100cm is much higher than that of 0-70cm. In the end of the experiment(October), the soil salt is gathered in the surface soil layer by the water evaporation. The 0-20cm soil salt content has high yield increase. The 0-10cm soil salt content of the control was 2.61ms/cm.Which is 3.2 times of litter shield and 2.5 times of fixing agent shield. The 0-10cm soil salt content of the Biological shrub area was about 1.5ms/cm. The content of soil organic matter shows different protection treatment higher than the control in 0-30cm soil layer. The average value of soil organic matter under litter shield is 1.65 times that of control.With the increase of soil depth,This difference is gradually disappearing.The pH value of soil showed the fixing agent shield is significantly lower than that of control in 0-30cm and 30-60cm soil layer.The litter shield and composite protect is lower than that of control only in 0-30cm. (4)On the desert-oasis ecotone,the one-time irrigation about 135L·m-2 in early spring can ensure the annual growth of Haloxylon ammodendron seeding. It`s different from the irrigation system of farmland protection forest, which need repeated irrigation in one year. There is of great significance to the construction of ecological protection on the desert-oasis ecotone. The plant height, the crown width and the diameter of Haloxylon ammodendron seeding reach maximum value under the litter shield and fixing agent shield,higher than the control 17.8cm、44.1dm2、4.5mm and 10.2cm、25.5dm2、4.14mm respectively. The max growth rate of the height, the crown width, the diameter and new shoots length of Haloxylon ammodendron seeding appeared in June to August. By September the growth rate of Haloxylon ammodendron seeding became slow down.The crown width and new shoots length even negative growth. While the Haloxylon ammodendron seeding crown and the diameter of the biological protect and composite protect were significantly lower than the control.
学科领域环境工程
语种中文
文献类型学位论文
条目标识符http://ir.xjlas.org/handle/365004/14691
专题研究系统_荒漠环境研究室
作者单位中科院新疆生态与地理研究所
推荐引用方式
GB/T 7714
刘璐. 不同防护措施对土壤水盐含量和梭梭生长的影响[D]. 北京. 中国科学院大学,2016.
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