沼液滴灌对次生盐渍化土壤不同土层理化性质的影响

The Effect of Biogas Slurry Drip Irrigation on the Physical and Chemical Properties of Different Soil Layers in Secondary Salinization Soil

【目的】探究沼液对南疆次生盐渍化土壤不同土层理化性质的影响。【方法】针对阿拉尔灌区次生盐渍化土壤,将沼液改良盐碱土的方法与滴灌相结合,采用室内土柱模拟实验的方法,设置CK、T0、T1、T2和T3共5个处理,分别用0(全水)、20%、40%、60%和80%稀释浓度梯度的含沼液进行沼液滴灌施用试验,研究不同沼液浓度对0~20 cm、20~40 cm、40~60 cm深度次生盐碱土层土壤容重、pH值、碱化度、全盐和土壤水稳性团聚体含量的影响。【结果】1)与CK对照处理相比,T0、T1、T2、T3沼液滴灌处理0~60 cm各土层的土壤容重、pH值、碱化度均显著降低,沼液处理容重、碱化度各深度土层降幅均为T3>T2>T1>T0,pH值各土层降幅均为T2>T3>T1>T0。2)各沼液滴灌处理土壤全盐含量均高于CK处理,土壤出现了盐分累积现象,T0、T1、T2、T3处理相较于CK处理含盐量增幅分别为1.3%~1.9%、5.5%~6.7%、9.8%~14.8%、13.0%~18.8%,表明沼液浓度越大,含盐量越高,越易引起土壤土层盐分的上升。3)沼液对土壤水稳性团聚体影响较大,沼液滴灌处理0~60 cm深度土层各级别水稳性团聚体百分数均高于CK处理,沼液处理组之间,T3处理土壤各级别水稳性团聚体百分数显著高于T1和T0处理,表明沼液浓度越高,越有利于土壤团聚体的形成,显著增加土壤的各级别水稳性团聚体数量。【结论】滴灌施入沼液在降低次生盐碱化土壤容重、pH值、碱化度和增强土壤团粒结构等方面都具有积极作用,本研究可为南疆地区次生盐碱地的综合利用提供理论依据和技术指导。

[Objective]To investigate the effects of biogas slurry on the physicochemical properties of different soil layers in secondary salinized soils in southern Xinjiang.[Method]For the secondary saline alkali soil in the Alar irrigation area,the method of improving saline alkali soil with biogas slurry was combined with drip irrigation.An indoor soil column simulation experiment was conducted,with five treatments including CK,T0,T1,T2 and T3.Experiments were conducted on drip irrigation of biogas slurry with concentration gradients of 0(total water),20%,40%,60%,and 80%to investigate the effects of different concentrations of biogas slurry on soil bulk density,pH value,alkalinity,total salt,and soil water stability aggregates in secondary saline alkali soil layers at depths of 0~20 cm,20~40 cm,and 40~60 cm.[Result]1)Compared with the CK control treatment,the soil bulk density,pH value,and alkalinity of each soil layer in the 0~60 cm layers were significantly reduced in the T0,T1,T2,and T3 slurry drip irrigation treatments.The soil bulk density and alkalinity of each depth layer in the slurry treatment decreased by T3>T2>T1>T0,and the pH of each soil layer decreased by T2>T3>T1>T0.2)The total salt content of the soil in each drip irrigation treatment with biogas slurry was higher than that in the CK treatment,and salt accumulation occurred in the soil.The increase in salt content in T0,T1,T2 and T3 compared to the CK treatment was 1.3%~1.9%,5.5%~6.7%,9.8%~14.8%and 13.0%~18.8%,respectively,indicating that the higher the concentration of biogas slurry,the higher the salt content,and the more likely it is to cause an increase in soil salinity.3)Biogas slurry has a significant impact on soil water stable aggregates.The percentage of water stable aggregates at all levels in the 0~60 cm depth soil layer treated with biogas slurry drip irrigation is higher than that of the CK treatment.Among the biogas slurry treatment groups,the percentage of water stable aggregates at all levels in T3 soils is significantly higher than that in T1 and T0 treatments,indicating that the higher the concentration of biogas slurry,the more favorable it is for the formation of soil aggregates and significantly increases the number of water stable aggregates at all levels in the soil.[Conclusion]Drip irrigation with biogas slurry has a positive effect on reducing soil bulk density,soil pH,alkalinity and enhancing soil aggregate structure in secondary saline alkali soils.This study can provide theoretical basis and technical guidance for the comprehensive utilization of secondary saline alkali soils in southern Xinjiang.