排水暗管间距对滨海盐土淋洗脱盐效果的影响

Effect of subsurface drain spacing on elution desalination for coastal saline soil

为合理设计盐碱土灌排改良工程,提高盐碱土改良效果,该文通过田间试验,研究了排水暗管间距对滨海盐土淋洗脱盐效果的影响。结果表明,漫灌淋洗期间,吸水管间距埋设越小,小区暗管系统稳定排水流量越大,淋洗初期的排水矿化度也越大,排水排盐效率越高;相同淋洗用水量下,3m间距小区田间各点土壤脱盐比较均一,6、9m间距小区田间各点土壤脱盐效率相差较大,3次淋洗后3个小区田间各点0~1m深土体土壤脱盐率分别在70.93%～73.40%、64.68%～77.47%、56.54%～78.78%;利用暗管工程技术参数估算方法预测了淋洗改良后田间各点土壤含盐量,不同间距吸水管上方0~1m深土体土壤含盐量预测值与实测值差异较大,其他各点差异较小,预测误差率在±10%左右。排水暗管间距对田面各点土壤脱盐效果影响很大,盐碱土灌排改良应合理设计暗管间距和采取有效的淋洗措施。

In order to design reasonably irrigation and drainage engineering and improve saline soil effectively, and investigate effect of the drain spacing on desalination of soils, leaching experiments were carried out on drained coastal saline soils laid 3, 6 and 9 m spaced subsurface drains respectively. The results showed that, during the leaching stage the drainage discharges in three experimental plots were great early, then decreased and kept stable roughly several days later. The drain spacing was smaller, the greater the stable drainage discharge among three plots, and the drainage water salinity was greater also at the early stage of three times leaching. The same leaching water column, desalinization of soils in the plot with 3 m spaced subsurface drains was more uniform, and was not very uniform with 9 m spaced subsurface drains. After three times leaching, the desalinization rates of 0-1 m soil layer in the plots with 3, 6 and 9 m spaced drains were 70.93%-73.40%, 64.68%-77.47% and 56.54%-78.78% respectively. The equation was applicable to estimate soil salinity variation in the flooded and pipe-drained field, and the prediction error was a little more at the sites above drains, but was 10% or so at the other sites between drains.