有机物添加对河套灌区碱化土壤理化性质与有机碳密度的影响

Effects of organic matter addition on the physicochemical properties and organic carbon density of alkalinized soil in Hetao Irrigation Area

【目的】提高河套灌区碱化土壤有机碳含量、耕作层土壤的保水保肥能力和土地可持续生产能力。【方法】以河套灌区轻度碱化土壤为研究对象,于2019—2020年通过田间定位试验,设置生物炭添加、牛粪添加、羊粪添加、玉米秸秆添加和常规施肥(对照)5个处理,以春季秸秆全量还田为基准,即有机碳量为2400 kg/hm^(2)添加,对0~60 cm土层土壤理化性质和有机碳密度进行分析。【结果】生物炭处理与对照相比,0~30 cm土层的pH值下降4.4%、碱化度下降0.4%、有机碳密度提高30.9%;30~60 cm土层的pH值下降2.3%。牛粪处理与对照相比,0~30 cm土层的速效钾含量提高45.2%、全氮含量提高38.0%、>2 mm和0.25~2 mm的水稳性团聚体增加158.05%和81.51%、有机碳密度提高52.4%;30~60 cm土层的速效钾含量提高35.6%、速效磷含量提高41.7%。羊粪处理与对照相比,0~30 cm土层的全氮含量提高30.0%、>2 mm的水稳性团聚体增加357.45%;30~60 cm土层的速效磷含量提高39.1%。秸秆处理与对照相比,0~30 cm土层>2 mm和0.25~2 mm的水稳性团聚体增加77.62%和83.01%。【结论】不同有机物对河套灌区轻度碱化土壤的理化性质发挥着不同程度的作用。生物炭添加对土壤盐碱性改良效果较好;牛粪和羊粪添加对土壤理化性质及土壤养分的补充效果较好,而牛粪实际施用成本及施用对土壤理化性质的改善和有机碳库的补充综合效果最好,利于土地保水保肥和持续生产,值得在河套灌区进行推广。

【Objective】To improve the organic carbon content of alkalinized soil,and the ability of water and fertilizer conservation in cultivated soil and sustainability of land-use in Hetao Irrigation Area.【Methods】Taking the lightly alkalinized soil in Hetao Irrigation Area as the research object,five treatments including addition of biochar,addition of cow manure,addition of sheep manure,addition of corn straw and conventional fertilization(control)were set up in the field positioning experiment from 2019 to 2020.The total amount of straw returned to the field in spring was taken as the benchmark,that is,the amount of organic carbon was 2400 kg/hm^(2).The physicochemical properties and organic carbon density of 0-60 cm soil layer were analyzed.【Results】Compared with the control group,the pH value of the 0-30 cm soil layer was decreased by 4.4%,the alkalinization degree was decreased by 0.4%,the organic carbon density was increased by 30.9%;and the pH value of 30-60 cm soil layer decreased by 2.3% treated with addition of biochar.Compared with the control group,the available potassium content in 0-30 cm soil layer was increased by 45.2%,the total nitrogen content was increased by 38.0%,the water-stable aggregates larger than 2 mm and 0.25-2 mm were increased by 158.05% and 81.51%,the organic carbon density was increased by 52.4%;and the content of available potassium and available phosphorus in 30-60 cm soil layer was increased by 35.6% and 41.7% respectively treated with addition of cow manure.Compared with the control group,the total nitrogen content in 0-30 cm soil layer was increased by 30.0%,and the water-stable aggregates larger than 2 mm was increased by 357.45%;and the content of available phosphorus in 30-60 cm soil layer was increased by 39.1%treated with addition of sheep manure.Compared with the control group,the water-stable aggregates larger than 2 mm and 0.25-2 mm in 0-30 cm soil layer were increased by 77.62% and 83.01% treated with addition of corn straw.【Conclusion】Different organic matter had different effects on the physicochemical properties of the slightly alkaliznied soil in Hetao Irrigation Area.The addition of biochar had a good effect on soil salinity and alkalinity improvement.The effect of addition of cow manure and sheep manure on soil physicochemical properties and soil nutrients was better,while the comprehensive effect of applying cow manure on soil physicochemical properties and organic carbon pool was the best,which was conducive to soil water and fertilizer conservation and sustainable production in Hetao Irrigation Area.