不同土层加入生物质炭对盐分淋洗的影响

Effect of biochar on salt leaching in different soil layers

生物质炭作为土壤调理剂,能够显著地改良和培肥土壤,但对盐渍化土壤盐分淋洗的影响缺乏研究和了解。本研究采用土柱模拟试验,将蘑菇棒生物质炭以质量比10%,添加到内蒙古河套地区硫酸盐盐渍化土壤0～20 cm,0～35 cm和0～70 cm的土层中,并进行淋洗,测定淋出液和土壤盐分及主要盐分离子含量,以期了解生物质炭对土壤盐分和主要盐分离子洗脱的影响。结果表明：加入生物质炭的土柱,淋洗液出流的时间提前了34～37d,电导率降低至〈5 mS.cm-1,需要的时间缩短了94～101 d;比起0～20 cm和0～70 cm土层加入生物质炭处理,0～35 cm土层加入生物质炭淋出液出流时间最早,盐分洗脱的效果最好。生物质炭对盐分离子淋洗也产生不同的影响,促进Na＋、K＋和Mg2＋的洗脱,但抑制Ca2＋洗脱;在淋洗初期生物质炭促进Cl-和SO42-洗脱,后期促进了HCO3-和CO32-的洗脱。可见,生物质炭可用作盐渍化土壤调理剂,不仅缩短盐分洗脱时间,而且还可以提高洗盐效率。

Biochar ,as a soil conditioner ,is little known on its impacts on salt leaching of saline soil .In this exper-iment ,10% rates of mushroom medium biochar was added into different layers （0~20 cm ,0~35 cm ,0~70 cm ） in a sulfate saline soil column collected from Hetao area in Inner Mongolia .Following washing with deionized water ,the elu-ent was collected and measured for electrical conductivity （EC ） and main ion contents .The study aims to investigate the effect of adding biochar into the different soil layers on leachings of salts and ions .The results showed that the eluent from biochar-amended columns appeared much earlier ,by 34~37 days .The time for EC reduction to lower than 5 mS＆#183; cm-1 was shortened by 94~101 days .Adding biochar into the soil layer of 0~35 cm achieved earlier eluent and better leaching effect compared with other two treatments in which biochar was added into 0~20 cm and 0~70 cm soil layer . Biochar addition had different impacts on ion leaching .It promoted leaching of Na＋ ,K＋ and Mg2＋ ,but inhibited Ca2＋leaching out of soil .Biochar addition promoted the leaching of both Cl - and SO42- at early stage and the leaching of HCO3 - and CO32- at late stage .The obtained result may imply that the biochar amended into saline soil as a soil condi-tioners could shorten salt leaching time and increase salt leaching efficiency as well .