半干旱地区海水灌溉下滨海盐土水分特征的研究

Study on moisture characteristics of marine saline soil irrigated with seawater in semiarid region

在山东莱州进行海水与淡水混合灌溉田间小区试验 ,发现高海水比例灌溉在干旱、半干旱地区具有明显的保水作用。海水灌溉下土壤水分变化特征如下 :(1)在半干旱地区 ,0～ 5 0cm土体土壤含水量主要受灌溉、降雨及蒸发等因素的影响 ,但从表层到下层 ,变化越来越小 ;随着灌溉水中海水比例的增加 ,0～ 5 0cm土体土壤水吸力逐渐降低 ,土壤含水量逐步提高 ,土壤保水能力提高了 4 0 %～ 6 0 %。 (2 )不同比例海淡水混灌 (A 0∶1;B 1∶9;C 1∶3;D 1∶1) ,使不同剖面的土壤水吸力产生明显的变化 :除 30cm土层土壤水吸力以处理B最大外 ,5 ,15和 5 0cm土层土壤水吸力大小均依次为处理A、B、C、D。 (3)各灌溉处理 6～ 8h后土壤水吸力均下降到最低点 ;70～ 80h ,在 5～ 15cm土层A、B两处理土壤水吸力增幅变大 ;灌溉后 4 8h处理A、B与C、D在 5cm土层土壤水吸力开始产生显著差异 ,随着时间的推移 ,差异加大。而 15cm土层 ,这种差异始于灌溉后 6 0h。 30cm土层各处理间土壤水吸力在灌溉后 7～ 8d内基本一致。

The field experiments of irrigation with seawater mixed with fresh water were carried out in Laizhou,Shandong Province The results showed that high proportion of seawater irrigated had a function of water conservation in arid and semiarid region Characteristics of the soil moisture irrigated with seawater were as follows: (1)In semiarid region,the soil moisture content in 050 cm soil layer was affected mainly by irrigation,rainfall and evaporation etc But this effect became smaller with the depth of soil As the proportion of seawater increasing,soil water suction in 050 cm soil profile became lower while soil moisture content increased gradually,and the capacity of water conservation increased 40%60% or so (2)The soil water suction in different soil layers changed significantly with the proportions of seawater The soil water suction in 5,15 and 50 cm soil layer of different treatment was in following order: A,B,C,D,except in 30 cm soil layer,B got the highest water suction (3)All of the soil water suction decreased to the smallest in 68 hours after irrigation The soil water suction in the 515 cm of soil layer produced high increase in 7080 hours after irrigation The soil water suction in 5 cm soil layer of the treatments of A and B differed evidently from C and D in 48 hours after irrigation As the time prolonged,the difference became larger This case was also found in 15 cm of soil layer in 60 hours after irrigation The soil water suction in every treatment of 30 cm soil layer was almost identical