围垦后滨海湿地土壤盐分动态研究

发布时间：2018-04-16 12:39

本文选题：崇明岛 + 盐分动态　；参考：《华东师范大学》2015年硕士论文

【摘要】：近年来,随着土地需求的增加,滨海地区多采用围垦的手段扩大耕地面积。但由于围垦改变了原先滩涂湿地潮汐交流的水文条件,湿地的土壤盐分动态也会随之改变。本研究采用土壤、植被和微气象长期连续监测的方法获得了围垦后土壤盐分长期变化的数据；分析了在不同时间尺度上盐分的动态规律；用模型的方法估算了围垦区芦苇湿地的蒸发散；并研究了蒸发散和降雨与土壤盐分动态的相关性,探讨了影响土壤盐分动态的机理。为围垦湿地土壤盐渍化的综合治理提供了一定的参考依据。研究的主要结果如下：(1)在年际动态方面,崇明东滩围垦区芦苇湿地耕层土壤在围垦后,由于该地区年均降雨量大于年均蒸散量,总体上土壤每年仍能以一定的速率降低。10cm土层的土壤盐分在所监测的6年间年均降低7.94%,30cm土层的土壤盐分在2009至2012年间年均降低6.06%。(2)在季节动态方面,土壤盐分在大多数年份里呈春、夏、秋升高,冬季降低的趋势。其中春季上升缓慢,夏季和秋季波动较大,升高与降低交替进行,秋季盐分积累最为严重,冬季,土壤盐分都会在迅速降低后会维持在较低水平。(3)在日动态方面,10cm土层的土壤盐分呈黎明前最低,下午2点左右最高的波动趋势,30cm土层的土壤盐分变化稍有滞后,且1 Ocm土层土壤盐分波动情况比30cm土层剧烈。(4)芦苇湿地的蒸发散在春季和冬季与表层土壤盐分动态存在显著相关,而在夏季和秋季无显著相关。降雨对土壤盐分的淋溶作用存在滞后效应,在大降雨事件发生后的7天内,1Ocm土层和30cm土层土壤盐分均有显著下降的趋势,且1Ocm土层下降速率呈先快后慢的趋势,30cm土层下降速率平稳。
[Abstract]:In recent years, with the increase of land demand, coastal areas use the means of reclamation to expand the area of cultivated land.However, because reclamation changed the hydrological conditions of tidal exchange, the soil salinity dynamics would change.In this study, soil, vegetation and micrometeorological long-term monitoring methods were used to obtain the long-term changes of soil salinity after reclamation, and the dynamic laws of salinity were analyzed at different time scales.The evapotranspiration of Reed wetland in reclamation area was estimated by using the model method, and the correlation between evaporation and rainfall and soil salinity dynamics was studied, and the mechanism of affecting soil salt dynamics was discussed.It provides a certain reference for comprehensive management of soil salinization in reclaimed wetland.The main results of the study are as follows: (1) in terms of interannual dynamics, the annual rainfall of Reed wetland topsoil in Chongming Dongtan Reclamation area is greater than that of annual evapotranspiration after reclamation.As a whole, the soil salinity of the soil layer of 10 cm can still decrease at a certain rate at a certain rate per year in the six years monitored. The soil salinity of the soil layer of 7.94 ~ 30 cm is decreased by 6.06% per year from 2009 to 2012) in the aspect of seasonal dynamics, the soil salinity of the soil can be reduced at a certain rate per year.Soil salinity increased in spring, summer and autumn and decreased in winter in most years.Among them, the rise in spring is slow, the fluctuation in summer and autumn is great, the increase and decrease are alternately carried out, the salt accumulation in autumn is the most serious, and in winter,The soil salt content of 10cm soil layer was the lowest before dawn in the daily dynamic aspect, and the soil salt content of 30cm soil layer had a slight lag in the peak fluctuation trend around 2: 00 pm, and the soil salt content of 10cm soil layer was lower than that of the soil salt content in the soil layer of 30cm soil layer.Moreover, the fluctuation of soil salinity in Ocm soil layer was more intense than that in 30cm soil layer. 4) the evaporation and dispersion of Reed wetland in spring and winter were significantly related to the salinity dynamics of surface soil, but there was no significant correlation in summer and autumn.The precipitation had lag effect on the leaching of soil salt, and the salt content in the soil layer of 1 Ocm and 30cm layer decreased significantly within 7 days after the heavy rainfall event.The decreasing rate of 1Ocm soil layer was first faster then slower than that of 30 cm soil layer.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S152.7

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