施肥条件下瘠薄红壤的物理肥力恢复特征

EFFECT OF FERTILIZER APPLICATION ON PHYSICAL PROPERTIES OF INFERTILE RED SOILS

在中国科学院红壤生态开放实验站布置田间长期定位试验,研究施肥条件下瘠薄红壤的肥力恢复特征,本文报道土壤物理性状的变化.结果表明,施用有机肥处理的大团聚体含量比单施化肥处理高100～150g/kg.施用有机肥6年,旱作条件下大团聚体含量达到500～600g/kg,已接近丰产桔园红壤的含量水平,而单施化肥处理为400～450g/kg,比一般红壤条件还低.耕种6年后,红壤的容重降至0.9～1.1mg/cm3.施用有机肥还提高土壤的总孔隙度1%～8%;提高传导孔隙的比例3%～20%;使 >200μm孔隙的比例达到9.6%～%18.9%,平均14.6%,接近丰产桔园的水平;提高田间持水量0.7%～4.5%,显著增强土壤的持水能力.因此,有机肥施用是恢复和保持红壤物理肥力的重要而有效的措施.

A long-term field experiment was conducted at the Ecological Experimental Station of Red soil, Chinese Academy of Sciences in order to investigate rehabilitation of fertility in infertile red soils with application of fertilizers. The results showed changes in soil physical properties. The content of macroaggregates in the infertile red soils in the treatment of organic manure application was 100~150g/kg higher than that in the treatment of inorganic fertilizer application. Under upland conditions, in the infertile red soils that had been fertilized with organic manure for 6 years, the macroaggregate content reached 500~600g/kg, close to the level of the red soil in a high-yield citrus orchard. However, six-year application of inorganic fertilizers left the red soil 400~450g/kg of macroaggregates, which was lower than that in the red soil of CK. After cultivation for 6 years with organic manure, bulk density of the infertile red soils decreased to 0.9~1.1mg/m3. The application of organic manure also increased total soil porosity by 1%~8%, ratio of soil conducting pore space by 3%~20%, ratio of >200靘 pore space to 9.6%~18.9% with an average of 14.6%, and field moisture capacity by 0.7%~4.5%. Therefore, application of organic manure was an important and effective measure for rehabilitation and maintenance of physical fertility of red soil.