长期施用化肥对农田黑土有机碳和氮消长规律的影响

利用中国科学院海伦农业生态实验站黑土区的农田长期定位试验土壤(1990~2004年)为研究对象,研究了长期施用化肥对土壤有机碳和氮的消长规律的影响。结果表明,长期施用化肥,氮用量的增加对土壤有机碳含量的影响较大,使土壤有机碳含量降低,而对土壤氮素的含量影响较小;磷用量的增加对土壤有机碳含量的影响不大,但使土壤全氮含量下降较多,因而C/N比呈上升趋势;而钾用量的增加对土壤中的有机碳含量基本上没有影响,但使土壤全氮量下降明显,有效氮含量略有降低,C/N比呈现增加趋势。因此,通过调控化肥的用量可以维持土壤中的有机碳、全氮及有效氮含量,保持土壤的持续生产力,提高作物产量。

Soil organic carbon and nitrogen of black farmland growth and decline under a long-term experiment chemical fertilizer applications

Soil samples collected from the black farmland of the Agri-ecological Experiment Station of CAS at Hailun County were used to study the growth and decline of Soil Organic Carbon(SOC) and total N under a long-term fertilizers application.The results showed that long term Nitrogen fertilizer application caused greater SOC concentration declining,but a slightly changed of soil N concentration and relatively stabilized C/N ratio.Long-term phosphorous application had fewer effects on the rate of decreasing of SOC,but made total N concentration decline greatly and C/N tended to increase.Long-term potassium application made SOC,N and C/N ratio change in the same trend and caused the rate of decline of SOC to become smaller,C/N ratio increase accordingly.