基于EM38的滨海棉田土壤表观电导率空间变异与利用研究

The Spatial Variation of Apparent Soil Electrical Conductivity on the Root Area of Cotton Fields in Coastal Saline Soil

土壤盐渍化和次生盐碱化是制约黄河三角洲农业可持续发展的关键障碍因子,了解和评估耕地土壤盐分的时空动态是对其进行科学利用和改良的前提。本文以黄河三角洲滨海盐碱地棉田为研究对象,在降水集中月份前后用EM38-MK2大地电导率仪测量了棉花两个关键生育期土壤根系层0~0.375 m和0~0.75 m剖面的土壤表观电导率,深入分析了棉花根区土壤表观电导率在空间上的分布特征与影响因素。结果表明:1)在降雨前后,黄河三角洲滨海土壤盐分空间变异较大,达到或超过中等变异水平;2)通过对大地电导率进行校正,排除影响其读数的干扰因素影响,大地电导率能快速表征0~0.375 m/0~0.75 m两个关键层次土壤盐分状态,可有效用于滨海棉田的土壤盐渍化的监测和评估;3)结合黄河三角洲地区地形地貌特征、降水蒸发、作物综合长势等因素的区域调查,作者认为在区域尺度上,优化土地利用格局,加强农田基本水利建设;在田间尺度上,加强土地平整和灌排配套等措施是治理和改良滨海盐碱土的基础。

Soil salinization and secondary salinization were the key obstruction factors which restricted the agricultural sustainable development of the Yellow River delta. Understanding and evaluating the spatial-temporal dynamics of farmland soil salinity was the premise to use and improve it scientifically. The cotton filed in the coastal saline-alkali land of the Yellow River delta was selected as research object in this paper. EM38- MK2 earth conductivity meter was used to measure the apparent conductivity of soil root layers(0 ~ 0.375 m and 0 ~ 0.75 m) at the two key growth periods before and after the precipitation concentrated months, meanwhile the spatial distribution characteristics and influence factors of apparent conductivity in the cotton root zone soil were analyzed. The results showed that: 1) before and after the precipitation, the spatial variation of coastal soil salinity at Yellow River delta was up to or over medium level; 2) after correcting earth conductivity and eliminating interference factors for reading, the earth conductivity of the two key soil layers(0 ~ 0.375 m and 0 ~ 0.75 m) could be rapidly determined, which could be effectively used to monitor and evaluate the soil salinization in coastal cotton field; 3) Based on the region survey of landform and crop growth condition in the Yellow River delta region, we suggested that it should be optimized land use pattern and strengthened the infrastructure of irrigation and water conservancy at the regional scale. For the field scale, strengthening land consolidation and setting up a complete set of irrigation and drainage measure were the basis for management and improvement of coastal saline soil.