不同治理措施对盐碱土团聚体组成和碳氮的影响

Effects of Different Treatment Measures on the Composition and Carbon and Nitrogen of Saline-alkali Soil Aggregates

以内蒙古科尔沁地区盐碱土为研究对象,采集不同治理措施下的盐碱土020、2030 cm和3050 cm土样分析其土壤团聚体组成和碳氮含量的变化。试验处理分为2个梯度中度M和重度L,空白处理(MCK、LCK)、铺细沙处理(MS、LS)、有机质处理(MY、LY)、腐殖酸处理(MF、LF)和脱硫石膏处理(MT、LT),研究人为治理措施对盐碱土团聚体组分和碳氮的影响,以期揭示不同治理措施下土壤有机碳、全氮的固持机制,为合理的治理措施提供参考依据。结果表明:中度盐碱对照和4种不同治理措施下土壤机械稳定性团聚体以<0.25 mm和0.252.00 mm粒经为主,重度盐碱以>5.00 mm为主;与中度盐碱对照相比,4种治理模式下不同土层<0.25 mm粒经明显增加;与重度盐碱对照相比,020 cm土层<0.25 mm粒经明显增加增加,>5.00 mm粒经明显减少,其它土层粒经无明显差异;与对照相比,不同梯度(中度、重度)4种不同治理措施下土壤有机碳不同程度地增加,MF>MY>MS>MT,并且随着土层的加深而降低,具有表矩形特征;与对照相比,不同梯度4种不同治理措施下土壤全氮不同程度地增加,中度盐碱020 cm土层MS>MF>MY>MT,其它MF>MS>MY>MT,重度盐碱020 cm土层MF>MS>MY>MT,2030 cm土层MF>MY>MS>MT,3050 cm土层无显著差异MF比其它处理要低,并且随着土层的加深而降低。相对于对照盐碱化裸地,不同治理措施能够有效改善土壤团聚体特性,优化土壤主要理化性质,其中以添加腐殖酸为最佳治理措施。

Saline-alkali soils in the horqin region of Inner Mongolia were used as the research object,and soil samples of saline-alkali soils 0-20,20-30 cm and 30-50 cm under different treatment measures were collected to analyze the changes of their soil aggregate composition and carbon and nitrogen contents.The experimental treatments were divided into two gradients moderate M and severe L,blank treatment(MCK,LCK),fine sand spreading treatment(MS,LS),organic matter treatment(MY,LY),humic acid treatment(MF,LF) and desulfurization gypsum treatment(MT,LT).The effects of anthropogenic treatment measures on saline-alkali soil agglomerate fractions and carbon and nitrogen were studied to reveal the mechanisms of soil organic carbon and total nitrogen sequestration under different treatment measures,in order to provide a reference basis for reasonable treatment measures.The results showed that the mechanical stability of soil aggregates was dominated by <0.25 mm and 0.25-2.00 mm particle size in the moderately saline control and 4 different treatment measures,and >5.00 mm particle size in the heavily saline-alkali;compared with the moderately saline-alkali control,the <0.25 mm particle size in different soil layers increased significantly in the 4 treatment modes;compared with the heavily saline control,the <0.25 mm particle size in the 0-20 cm soil layer increased significantly.Compared with the control,soil organic carbon increased to different degrees under 4 different treatment measures in different gradients(moderate and severe),MF>MY>MS>MT,and decreased with the deepening of the soil layer,with the characteristic of surface rectangle;compared with the control,soil total nitrogen increased to different degrees under 4 different treatment measures in different gradients.Compared with the control,moderate saline-alkali 0-20 cm soil layer MS>MF>MY>MT,other MF>MS>MY>MT,severe saline-alkali 0-20 cm soil layer MF>MS>MY>MT,20-30 cm soil layer MF>MY>MS>MT,30-50 cm soil layer no significant difference MF was lower than other treatments and decreases with the deepening of soil layer.Compared with the control saline-alkali bare ground,different treatment measures can effectively improve the soil aggregate characteristics and optimize the main physicochemical properties of the soil,among which the addition of humic acid is the best treatment measure.