鄱阳湖地区长期施肥双季稻田生态系统净碳汇效应及收益评估

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，利用不同施肥处理作物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（不施肥（CK）、单施氮肥（N）、单施磷肥（P）、单施钾肥（K）、氮磷肥配施（NP）、氮钾肥配施（NK）、氮磷钾配施（NPK）、两倍氮磷钾配施（2NPK）、有机肥与氮磷钾肥配施（NPKM））双季稻生态系统的碳汇效应和经济效益。结果表明，有机肥和化肥配施（NPKM）既提高了系统的作物固碳量又显著增加了土壤的固碳量，使得其净碳汇效应最大，为8．78tC·hm^-2·a^-1；两倍氮磷钾配施（2NPK）系统的净碳汇效应为8．11tC·hm^-2·a^-1，二者均高于氮磷钾配施（NPK）处理的7．03tC·hm^-2·a^-1，不施肥及单施一种或两种无机肥配施系统的净碳汇效应均明显减弱，其中不施肥处理（CK）最小为4．52tC·hm^-2·a^-1，单施N肥比单施P、K肥在提高系统净碳汇效应上作用明显。配施有机肥（NPKM）稻田的作物产量和经济效益也高于无机肥配施处理（NPK和2NPK），不施肥、单施一种或两种无机肥配施稻田的作物产量和经济效益明显偏低。因此，稻田施用一定量的无机肥是提高稻田生态系统碳汇效应和经济效益的保证，而配施有机肥可以明显提高稻田生态系统的碳汇效应和经济效益。

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

The net carbon sink and economic benefits of double rice cropping ecosystem under long-term fertilization were estimated based on the measurement of rice yield, soil organic matter content and the investigation of material and management inputs, in Poyang Lake Field Reddish Paddy Soil Pivotal Observational and Experimental Station of Agricultural Ministry. The treatments includes： no fertilization（CK）; single N（N）; single P（P）; single K（K）; combined N and P（NP）; combined N and K（NK）; combined N, P and K（NPK）; double combined N, P and K（2NPK） and combined inorganic/organic fertilization （NPKM）. The carbon sequestration from crop and soil increased under combined inorganic/organic fertilization（NPKM） compared to that under inorganic fertilization only（NPK）. Increased inorganic fertilization （2NPK） did not improve ecosystem net carbon sink significantly. The net carbon sinks of NPK, 2NPK and NPKM were 7.03 t C·hm^-2·a^-1, 8.11 t C·hm^-2·a^-1 and 8,78 tC·hm^-2·a^-1, respectively. It reduced ecosystem carbon sink signifieantly under lower fertilization level and no fertilization ecosystem, the net carbon sink was 4.52 t C·hm^-2·a^-1under no fertilization（CK） ecosystem and it is the lowest in all the treatments. The difference of the economic benefits under different treatments was almost the same as that of ecosystem net carbon sink. The N fertilizer is better than P and K fertilizer on improving paddy field ecosystem net carbon sink and economic benefits in Poyang Lake region. The application of organic fertilizer besides inorganic fertilizer could increase both ecosystem net carbon sink and economic benefits; no fertilization and less fertilization reduced the ecosystem net carbon sink and economic benefits significantly. So, the proper inorganic fertilizer application is necessary to keep higher crop yield and improve ecosystem net carbonsink, the application of organic fertilizer besides inorganic fertilizer is an effective method to achieve the objective of the lower carbon and high quality agriculture.