淹水在苏打盐碱土形成过程中的作用——苏打盐碱土形成原因的探讨
Effects of soil submerging on the formation of saline-sodic soils——Discussion on the causes of saline-sodic soils and the effects of submergence
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摘要: 苏打盐碱土在我国松嫩平原西部地区广泛分布,它以透水性差,碱性强为主要特点,是世界上最难治理的一类障碍性土壤。近年来,该区土壤苏打盐碱化程度日益加剧,面积不断增加,亟待治理,而弄清苏打盐碱土形成的主要原因是有效治理的前提。本文对松嫩平原西部苏打盐碱土形成原因,从土壤地表景观格局、物理特征和化学性质方面进行了系统归纳与总结,概述了淹水对土壤盐分以及生物的影响,发现由于特殊的地形地貌,该区土壤过去经常处于淹水状态,长期的排水不畅导致区域内水分运动以上行为主,积盐作用强烈,淹水在苏打盐碱土形成和导致盐碱化加剧过程中起到了重要作用。文章同时从3方面提出了苏打盐碱土治理的有效对策与途径。Abstract: Saline-sodic soils are widely distributed in the west of Songnen Plain, Northeast China.These soils are regarded as the most difficult types of obstacle soils for improvement and utilization, because of their poor permeability and higher alkalinity.Recently, many studies have shown that the area and degree of salinity of saline-sodic soil have been ever-increasing in an unprecedented scale which raised the public concern.To improve and utilize the soil more effectively, the main cause of saline-sodic soil should be correctly illustrated and understood.In this review, we systematically analyzed and discussed the main factors on the formation of saline-sodic soils, including landscape pattern of surface, physical parameters and chemical properties and summarized the effects of soil submerging on the salt content and soil biota.We found that the west of Songnen Plain was usually remained in a flooding condition because of its special topography and landforms.Also, the impeded drainage caused water moving upward in the soil, which intensified the salt accumulation, and eventually exacerbated the condition of normal soil.Therefore, soil submerging makes an important contribution in exacerbating the saline-sodic soil condition.Meanwhile, we also proposed the priorities and practical ways in three aspects to manage the sodic-saline soil.