洞庭湖地区长期施肥条件下双季稻田生态系统净碳汇效应及收益评估

Evaluation of Net Carbon Sink Effect and Economic Benefit in Double Rice Field Ecosystem Under Long-term Fertilization

以农业部望城红壤水稻土生态环境重点野外观测试验站的长期定位肥力效应试验稻田为研究对象,利用历年作物产量、凋落物固碳和农田CO2排放等观测资料及生态系统的物质和管理投入等调查资料,估算了年碳汇平衡和经济收益,以及不同施肥处理的固碳速率、潜力及表土碳密度。结果表明,不同施肥处理下年碳汇量介于0.82～4.70tC.hm-2.a-1,增施有机肥(猪粪、稻草)的处理NPK+RS、NK+PM和NP+RS的碳汇量分别是相应的仅施化肥处理NPK、NK和NP的1.1、1.7和1.4倍。不同处理生态系统物质投入的碳成本介于0.03～0.65tC.hm-2.a-1,人工管理的碳成本介于1.42～1.48tC.hm-2.a-1,年经济收益介于1.17×103～8.71×103CNY.hm-.2a-1,有机肥配施的经济效益是单施化肥的1.1～1.6倍。不同施肥处理固碳速率介于25.83～51.98kg.hm-2.a-1,不同施肥处理表土碳密度介于29.21～43.24t.hm-2,增施有机肥能够提高土壤固碳速率和表土碳密度。与单施化肥相比,有机无机配施处理的生态系统生产力较高,也表现出较高的碳汇效应和经济收益,是促进土壤固碳减排的一项重要措施。

The annual C balance, economic benefit, Soil C sequestration rate and C density of surface soil in long-term fertilization double rice ecosystem were estimated, based on measurement of grain yield, litter C content and field CO2 emission as well as investigation of material and management inputs, in Wangcheng Field Reddish Paddy Soil Pivotal Observational and Experimental Station of Agricultural Ministry. The calculated annual C sink under different fertilizations ranged from 0.82 to 4.70 t C·hm^-2·a^-1, which C sink effect under combined inorganic/organic fertilization was 1.1, 1.7 and 1.4 times as that under relative chemical fertilization. C cost of material and management input ranged fro.m 0.03 to 0.65 t C·hm^-1·a^-1 and 1.42 to 1.48 t C·hm^-2·a^-1, respectively. Annual economic benefit ranged from 1.17 to 8.71 CNY·hm^-2·a^-1, and combined fertilization enhanced 1.1-1.6 times higher than chemical fertilization. Soil C sequestration rate under different fertilization ranged 3.98 to 16.30 kg·hm^-2·a^-1, C density of surface soil under different fertilization ranged 32.82 to 37.24 t·hm^-2. It indicated that increasing organic manure fertilizer has great effect on improving C sequestration rate and C density of surface soil. Comparing with that under chemical fertilization, The paddy ecosystem could not only have higher productivity, but also present greater net C sink and higher economic benefit under combined inorganic/organic fertilization. So it＇s an effective measure to increasing carbon sequestration and emission mitigation in soil.