添加秸秆及生物质炭对风沙土有机碳及其活性组分的影响

以宁夏贺兰山东路风沙土为研究对象,分析秸秆、生物质炭等碳量添加下土壤有机碳及活性碳组分的变化,为确定该地区最佳施肥措施提供科学理论依据。结果表明:添加生物质炭和秸秆均显著增加了土壤有机碳含量,与对照相比土壤有机碳含量分别增加了7.7%、7.5%。添加生物质炭有利于土壤易氧化有机碳、颗粒有机碳的积累,二者含量分别比对照增加49.6%、17.5%;而添加秸秆更有利于土壤微生物生物量碳、可溶性有机碳的积累,其含量分别比对照分别增加25.8%、59.9%。秸秆与生物质炭添加均显著增加了土壤速效氮、容重和黏粒含量,且以添加生物质炭增加作用更为明显,显著降低了土壤全盐、砂粒含量。土壤有机碳、可溶性有机碳、颗粒有机碳、易氧化有机碳与速效氮含量极显著正相关,与全盐、砂粒含量极显著负相关;土壤可溶性有机碳、颗粒有机碳、易氧化有机碳与容重极显著负相关;而土壤微生物生物量碳与理化性质之间无显著相关性。综上,在风沙土中添加生物质炭更有利于土壤活性碳库提升和理化性质改善,且以年添加量7 t/hm2以上为宜。

Effects of Biochar and Straw on Soil Organic Carbon and Fractions of Active Carbon in Aeolian Sandy Soil

Taking the sandy soil in eastern Helan road of Ningxia as the research object, the changes of soil organic carbon and active carbon components under the addition of straw and biochar were analyzed to provide scientific theoretical basis for determining the best fertilization measures in this area. The results showed that biochar and straw significantly increased the content and storage of soil organic carbon. The addition of biochar was beneficial to the accumulation of soil oxidized organic carbon and particulate organic carbon, while straw addition was more conducive to the accumulation of soil microbial biomass carbon and soluble organic carbon. The addition of straw and biochar significantly increased soil available nitrogen, bulk density and clay content, significantly reduced soil total salt and sand content, and the increase effect of biochar was more obvious. Soil organic carbon, soluble organic carbon, particulate organic carbon and readily oxidizable organic carbon were significantly positively correlated with available nitrogen content, and negatively correlated with total salt and sand content. Soil soluble organic carbon, particulate organic carbon and readily oxidizable organic carbon were significantly positively correlated with bulk density. However, there was no significant correlation between soil microbial biomass carbon and physical and chemical properties. In conclusion, adding biochar to aeolian sandy soil is more conducive to the improvement of soil active carbon pool and physical and chemical properties, and the appropriate annual addition amount is more than 7 t/hm_².