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为了解具有秸秆夹层层状土壤一维垂直入渗水盐分布特征,通过定水头入渗实验装置,在距土表以下20 cm设置一个秸秆夹层,研究了4种秸秆铺设量(0、6 000、12 000、18 000 kg/hm2)和2种秸秆长度(1、10 cm)的秸秆夹层对盐碱土入渗过程土壤水分和盐分分布的影响。结果表明,盐碱土中设置秸秆夹层具有良好的阻水性,累积入渗量和入渗速率明显下降,下渗水流在一定限度内滞留于秸秆层以上,秸秆夹层同时具有减渗性,使下渗水量明显减小;土壤盐分在秸秆夹层以下一定深度范围内出现峰值。秸秆长度影响盐分滞留深度,秸秆长度10 cm处理全盐含量最大值深度较秸秆长度1 cm处理有所下移;秸秆夹层也影响着水分入渗过程中离子的交换与吸附,Cl–入渗后在剖面深度的变化规律与全盐变化规律相同,HCO3–对秸秆夹层的敏感性明显强于SO42–,SO42–对水分依赖性较强,含水量足够大时才能引起它的快速运移。
In order to understand the characteristics of one-dimensional vertical infiltration of salt and water in stratified stubble soils, a straw interbed was set at 20 cm below the soil surface through a fixed-head infiltration experimental device. The effects of four straws laying on straw (0, 600, 12 000,18 000 kg / hm2) and two straws of straw length (1,10 cm) on soil moisture and salt distribution in saline-alkali soil infiltration process. The results showed that the straw intercalation in saline-alkali soil had good water-blocking property, and the infiltration rate and infiltration rate decreased obviously. The infiltration water flow was retained above the straw layer within a certain limit. The straw intercalation also had the ability of reducing infiltration, The amount of soil salinity peaked within a certain depth below the straw intercalation. The length of straw affected the depth of salt retention. The depth of maximum salt content of 10 cm straw length was lower than that of straw length 1 cm. The straw interlayer also affected the exchange and adsorption of ions during water infiltration. After Cl-infiltration The change of profile depth is the same with that of total salt. The sensitivity of HCO3- to straw interlayers is obviously stronger than that of SO42-. SO42- is strongly dependent on water content and water content is large enough to cause its rapid migration.