不同生物炭对南疆盐渍土盐分离子淋洗效果的影响

Evaluation of the Effectiveness of Different Biochar in Leaching Salt Ions from Saline Soil in Southern Xinjiang

为探究不同生物炭添加对盐渍化土壤盐分及离子淋洗效果的影响。采用室内土柱模拟试验,在土壤表层(0—10 cm)添加比例为0.5%的猪粪(PMB)、棉秆(CSB)和玉米秸秆(MSB)生物炭,淋洗过程分为急降(P1)、缓降(P2)和稳定(P3)3个阶段,通过测定淋洗速率、流量、累积浸出阴阳离子浓度、土壤剖面含水率和土壤剩余可溶性离子的含量来探究不同生物炭对南疆盐渍土盐分离子的淋洗效果。结果表明:与未添加生物炭处理(CK)相比,生物炭的施用能提高各阶段淋洗液的流量和淋洗速率,在电导率快速下降阶段CSB处理流量提高20%,PMB处理淋洗速率提高29%,MSB处理最先使EC值降低到5 mS/cm,但对离子的去除能力提升较小。生物炭的施用对各阶段离子淋出先后顺序有一定影响,即促进Ca^(2+)、Na^(+)、SO_(4)^(2-)和Cl^(-)淋出,抑制K^(+)淋出。淋洗结束时,生物炭均能显著降低土壤残余含盐量。CSB处理可提高表层土壤保水能力,使得钠吸附比(SAR)始终保持较低水平且对土壤中残余阴离子洗脱效果最好。表明CSB处理是一种非常有潜力的土壤改良剂。研究结果可为南疆盐渍化土壤改良提供理论参考。

To explore the differences and characteristics of the effects of different biochar additions on salinity and ion leaching in saline soil.This study used indoor soil column simulation experiments to add 0.5%of pig manure(PMB),cotton straw(CSB),and maize straw(MSB)biochar to the soil surface(0-10 cm),the leaching process was divided into three stages:rapid descent(P1),slow descent(P2),and stable descent(P3).To investigate the leaching effect of different biochar on salt ions in saline soil of southern Xinjiang,the infiltration rate,flow rate,cumulative leaching concentration of anions and cations,soil profile moisture content,and residual soluble ion content were measured.The results showed that compared to the treatment without adding biochar(CK),the application of biochar could improve the flow rate and infiltration rate of the leachate at each stage.During the rapid decline in electrical conductivity stage,the flow rate of CSB treatment increased by 20%,and the infiltration rate of PMB treatment increased by 29%.MSB treatment first reduced the EC value to 5 mS/cm,but the improvement in ion removal ability was small.The application of biochar had a certain impact on the sequence of ion leaching at each stage,that was,it promoted the leaching of Ca^(2+),Na^(+),SO_(4)^(2-),and Cl^(-),and inhibited the leaching of K^(+).At the end of leaching,biochar can significantly reduce the residual salt content of soil.CSB treatment can improve the water retention capacity of topsoil,keeping the sodium adsorption ratio(SAR)always at a low level and providing the best elution effect for residual anions in the soil.This shows that CSB treatment is a potential soil conditioner.The results provide theoretical reference for salinized soil improvement in southern Xinjiang.