鄱阳湖地区长期施肥双季稻稻田生态系统净碳汇效应变化特征

以江西省红壤所长期施肥红壤水稻土双季稻农田生态系统为研究对象,利用不同施肥年限作物的产量及土壤有机质含量等测定数据,结合调查获得的生态系统物质和管理投入资料,估算了不同施肥处理双季稻生态系统的碳汇效应和经济效益,并比较了不同施肥年限农田生态系统碳汇效应的变化特征。结果表明：有机肥与无机肥配施处理的净碳汇效应最强为-8.78 tC.hm-2.a-1,不施肥处理的净碳汇效应最弱为-4.86 tC.hm-2.a-1,加倍施加化肥虽提高了系统的净碳汇效应,但是作用不显著;不同施肥年限,相同施肥条件农田的作物固碳量和净碳汇效应没有显著性差异,但是土壤固碳量变化显著,施加有机肥可以维持和提高土壤的固碳能力平均达到0.41 tC.hm-.2a-1,在追求更高作物固碳量同时,提高和维持土壤的固碳能力也是提高农田碳汇效应的有效途径。有机肥与无机肥配施处理的平均经济效益为17 568 CNY.hm-.2a-1,也高于其他施肥处理。因此,适当施加有机肥不仅可以大幅提高农田生态系统的碳汇效应,还可以显著提高农业生产的经济效益,是实现低碳、高值农业的最有效措施之一。

Dynamic of Net Carbon Sink Effects and Economic Benefits in Double Rice Ecosystem Under Long-term Fertilization in Poyang Lake Region

The net carbon sink effects and economic benefits of double rice cropping system under long-term fertilization experiment were evaluated based on the determination of rice yield and soil organic matter content,as well as the investigation of material and management inputs in the Red Paddy Soil Observational and Experimental Station of Poyang Lake region.Results showed the carbon sink derived from crop and soil increased under inorganic/organic combined fertilization compared to that under unique inorganic fertilization.And the increasing input of inorganic fertilization did not significantly improve ecosystem net carbon sink.The net carbon sinks of unique inorganic fertilization,double unique inorganic fertilization and inorganic/organic combined fertilization were 7.03 tC·hm-2·a-1,8.11 tC·hm-2·a-1 and 8.78 tC·hm-2·a-1,respectively.Ecosystem carbon sink reduced significantly under no fertilization ecosystem with the net carbon sink was 4.86 tC·hm-2·a-1,and it is also the lowest among all the fertilization treatments.Carbon sink from crop and the net ecosystem carbon sink was almost constant at different fertilization time if under the same fertilization condition,however,soil carbon sink changed greatly with fertilization time.It is urgent to discover proper fertilization practice to maintain and improve soil carbon sink besides purely pursuing higher crop yield.In conclusion,combined using organic fertilizer with inorganic fertilizer could not only increase ecosystem net carbon sink but also the economic benefits.Thus,organic fertilization is an effective way to achieve the target of the lower carbon and high quality agriculture.