长期施肥条件下黑土有机碳和氮的动态变化

以黑土地区海伦农田生态系统国家野外科学观测研究站的农田长期(1990～2004年)肥料定位试验土壤为试验材料,对不同施肥处理有机碳和氮进行了系统分析。结果表明,长期不施化肥(CK),土壤中有机碳、全氮、碱解氮及C/N呈现下降趋势;长期施用氮肥,土壤有机碳亏损速率较大,但土壤氮素变化较小,C/N保持相对稳定;长期施用磷肥,土壤有机碳含量下降速率较小,但全氮含量下降速率较大,因而C/N保持上升趋势;长期施用钾肥,土壤有机碳、氮及C/N变化趋势相同,但土壤有机碳含量下降速率较小,C/N增加较快。因此,通过调控化肥可以维持土壤的有机碳、全氮及碱解氮含量,保持土壤的持续生产力及提高作物产量。

Dynamics of Soil Organic Carbon and Nitrogen in Black Soil under a Long-term Application of Fertilizers

Soil samples were collected from the black farmland of the Agri-Ecological Experiment Station of CAS in Hailun County,China.The changes of total organic carbon and total nitrogen in the soil of a long term experiment under different fertilizer application were systematically analyzed.The results showed that total organic carbon,total nitrogen,available N concentration and C/N ratio had a decline trend with long term fertilization.Long term Nitrogen fertilizer application caused greater derease in soil organic carbon(SOC) concentration,but a slightly changed in soil N concentration.Long-term Phosphorous fertilizer application had less effects on the decreasing rate of SOC,but made total N concentration declined greatly.Long term Potassium application made SOC,N and C/N ratio change in the same orientation.