添加秸秆对不同有机含量土壤腐质化特征及酸度的影响

Effects of Straw Addition on Humification Characteristics and Acid⁃ity of Soil with Different Organic Contents

通过向低、中、高及去有机质含量土壤处理中添加玉米秸秆进行室内培养试验,研究秸秆添加量对不同有机质含量土壤腐解能力及土壤酸度的影响。结果表明:在15℃恒温培养150 d后,土壤中秸秆腐解率表现为高有机质含量土壤>中有机质含量土壤>低有机质含量土壤>去有机质含量土壤,高有机质含量土壤均高于其他3种有机质含量处理腐殖化系数,且高有机质含量土壤有机质转化效果最好,有机质增加量最多。对于土壤酸度的影响,随秸秆添加量的增加,土壤pH上升幅度增加,土壤中交换性H^(+)、交换性Al^(3+)、交换性酸的含量降低。不同秸秆添加量条件下,4个有机质含量土壤表现不同,低有机质含量土壤秸秆添加量为10~15 g/kg时,土壤pH增幅最大,土壤交换性H^(+)、交换性Al^(3+)、交换性酸含量减幅最大,土壤酸度降幅最大;中、高有机质含量土壤秸秆添加量为15~20 g/kg时,土壤pH增幅最大,土壤交换性H^(+)、交换性Al^(3+)、交换性酸含量减幅最大,土壤酸度降幅最大。相对3种有机质含量土壤,去有机质含量土壤对降低土壤酸度的效果不明显。不同秸秆添加量和不同有机质含量的土壤中,交换性Al^(3+)含量远高于交换性H^(+),直接影响土壤交换性酸和土壤pH。秸秆还田在增加土壤有机质含量的同时还应有效降低土壤酸度,缓解土壤酸化。

By adding corn straw to soil with low,medium and high organic matter content and deorganic content for indoor culture experiments,the effects of straw addition on decomposition capacity and soil acidity of soil with different organic matter contents were studied.The results showed that after constant temperature incubation at 15℃for 150 days,the decomposition rate of straw in the soil showed as follows:high organic matter soil treatment>medium organic matter treatment>low organic matter soil treatment>deorganic soil treatment.At different stages of straw addition,the humification coefficient of soil with high organic matter content was higher than that of the other three organic matter content soil treatments,and the organic matter conversion effect of the high organic matter content soil treatment was the best,and the organic amount increased the most.With regard to the effect of soil acidity,with the increase of straw addition,soil pH value increased,and the contents of exchangeable H^(+),exchangeable Al^(3+),and exchangeable acid in the soil decreased.Under different conditions of straw addition,the four soil treatments with different organic matter contents showed different performances.The straw addition amount of low organic matter content soil treatment was between 10-15 g/kg,soil pH increased the most,the contents of soil exchangeable H^(+),exchangeable Al^(3+),and exchangeable acid decreased the most,and soil acidity decreased the most.The amount of straw addition for the two treatments of medium and high organic matter content soils was between 15-20 g/kg,the maximum increase was shown in soil pH,the contents of soil exchangeability H^(+),exchangeable Al^(3+),and exchangeable acid content decreased the most,and soil acidity decreased the most.Compared with the previous three organic matter content soil treatments,deorganic soil treatment had no obvious effect on reducing soil acidity.The content of exchangeable Al^(3+)in soil with different straw additions and different organic matter contents was much higher than that of exchangeable H^(+),which directly affected soil exchangeable acid and soil pH.Therefore,returning straw to the field can effectively reduce soil acidity and relieve soil acidification while increasing the content of soil organic matter.