黄河三角洲地区棉田土壤盐分的时空分布特征研究

Study on Spatial and Temporal Distribution of Soil Salinity in Cotton Field in the Yellow River Delta

黄河三角洲地区是我国重要的后备耕地资源,明确土壤盐分的空间变异特征是充分开发该地区土地资源的基础。本试验选取黄河三角洲地区典型土地利用类型棉田,沿黄河入海方向自内陆至海岸布设采样带,研究0~100 cm土层土壤盐分在剖面及空间的分布特征。结果发现,沿黄河入海方向自西向东土壤盐分呈上升趋势,与成土时间、距海远近和人类活动密切相关。整个采样区(利津县北宋镇至河口区孤岛镇)棉田土壤盐分以轻盐土为主,受人为耕作管理影响0~60 cm土壤条件趋于一致,空间变异性小于60~100 cm土层;研究区土壤盐分剖面类型以表聚型为主,分布在研究区的近海段,随着人类耕作熟化影响时间的加长和距海距离的增加,土壤盐分剖面由表聚型向振荡平均型和底聚型发展。合理的土地耕作在一定程度上可以减轻土壤盐渍化,在后期种植管理中应参照研究区土壤盐分等值线图,采取恰当的农田管理方式,降低土壤盐渍化,防止次生盐渍化的发生。

The Yellow River delta is an important reserve cultivated land resources in China. To make clear the spatial variability of soil salinity is the basis of exploiting land resources in this area. In this study, the profile and spatial distribution characteristics of soil salinity in 0 - 100 cm soil layer in the typical land use type of cotton field were studied with sampling from inland to the coast along the Yellow River. The results found that the soil salinity along the Yellow River from inland to coastal areas was gradually increasing, which was closely related to the soil forming time, the distance from the sea and human activities. The study area was mainly light saline soil, and under the influence of artificial cultivation management, the spatial variability of 0 - 60 cm soil layer tended to be consistent, which was smaller than that of 60 - 100 cm soil layer. Surface ac- cumulation was the main soil salinity profile type in the study area and mainly distributed in the coastal area of the study area. Along with the increase of human cultivation time and the distance from the sea, the soil salin- ity profile type was gradually transformed into the oscillating average type and bottom accumulation type. It showed that reasonable land management could reduce the soil salinization to some extent. In the late planting management, we should refer to the isogram of soil salinity in the study area and take appropriate farmland management ways to reduce the soil salinization and prevent the occurrence of secondary salinization.