土壤有机质是形成土壤肥力的核心物质,是植物有机营养物质在土壤中的主要存在形式。土壤有机质含量在很大程度上影响着土壤的性质,左右着土壤肥力水平。国内外试验研究证明:作物产量所吸收的养分60-90%来源于土壤,只有10-40%来源于当年土壤。林口县耕地土壤有机质下降速度较快,由六、七十年代的4-6%,下降到现在的2-3.5%。土壤有机质含量的急剧下降,造成土壤理化性状不断恶化,土壤容重增加,孔隙度减少,通透性变 Soil organic matter is the core material of soil fertility and the main form of plant organic nutrients in the soil. Soil organic matter content greatly affects the nature of soil, soil fertility around the level. Tests at home and abroad have proved that 60-90% of the nutrients absorbed by crop production come from the soil, and only 10-40% of the soil is derived from the current year. The soil organic matter in cultivated land in Linkou County decreased rapidly from 4-6% in 1960s and 1970s to 2-3.5% now. Soil organic matter content dropped sharply, resulting in deteriorating soil physical and chemical properties, soil bulk density increased porosity decreased permeability change