不同干扰强度对滩涂围垦区土壤颗粒组成的时空分异特征的影响

Effects of Disturbance Intensity on Spatio-temporal Differentiation of Soil Particle Size in Reclamation Areas of Tidal Flat

滩涂是陆地与海洋间重要的生态交错带以及生态系统之一,随着沿海地区经济的发展,滩涂围垦成为缓解区域土地利用压力的重要途径之一。论文通过对不同围垦年限以及不同人类干扰强度下土壤粒径分布(Particle Size Distribution)的时空差异研究,比较了自然演变和人类活动双重影响下,垦区环境的变化过程及影响因素。结果表明:1)在60 a的围垦过程中,在强烈、中度和无人类干扰强度下,土壤粒径分布均表现出在脱盐过程中随围垦年限增加而砂粒减少、粉粒和粘粒增加的过程,脱盐后砂粒的年均下降率可达0.72%;2)在无干扰强度下,土壤粒径分布反映出滩涂围垦和脱离海水影响的自然过程,而强烈和中度干扰强度则在此基础上反映出人为和自然干扰的综合效果;3)耕种方式、时间以及土壤侵蚀等因素均会对土壤粒径分布的变化强度造成影响而表现出显著的空间差异性;4)土壤粒径的时空分布可以综合反映出滩涂围垦区的环境特点,对指导垦区内土地资源的合理开发利用具有重要意义。在长期的围垦过程中,不同的开发利用时间及区位表现出了不同的关键影响因素,使垦区内土地利用格局和资源配置仍存在诸多不合理之处,随之带来相应的环境问题必须引起重视,为未来滩涂围垦区的合理规划提供理论依据。

Tidal flat is one of the important ecotones and ecosystems between land and sea,but tidal flat reclamation has been an important way to release the increasing pressure of landuse due to the economic development in coastal regions.We analyzed the spatio-temporal differentiation of particle size distribution（PSD） on tidal flat with different years of reclamation and different intensities of disturbance,and compared the effects from natural succession and human activities on the process of environment change in the reclaimed zones.The results demonstrated： 1） During 60 years of reclamation,with the growth of reclamation period the content of sand decreased while those of silt and clay increased under all levels disturbance,and the decreasing rate of sand could reach 0.72% per year after desalination.2）With no disturbance,the soil PSD could reflect the physical process of tidal flat being reclaimed and separated from the sea water,while under the intense natural and artificial disturbances it would reflect the integrated effects of both factors.3） Cultivated methods,time and soil erosion would all induced significant spatio-temporal differentiation of PSD.4） The spatio-temporal differentiation of PSD in reclaimed zones could generally demonstrate the environmental characteristics of tidal plat,and had significance in developing land resources in reclaimed tidal flat.During the long-time reclamation of tidal flat,the key affect factors were different in different regions at different stages,which lead to many unreasonable phenomena of land use pattern and resources allocation,and caused dramatic changes and fluctuations in soil environment.The correlation between natural resources and human activities should be carefully assessed.