上海崇明生态农业园区花菜田的碳平衡

以上海崇明岛生态农业园区花菜Brassica oleracea var.botrytis田为研究对象,主要运用生物量法对花菜田植被碳储量、土壤呼吸及人工管理碳源进行测定,估算花菜田碳平衡情况,旨在通过对花菜田碳平衡的估算,探讨农田碳增汇减排措施。研究表明:①花菜在1个生育期内含碳率最小值为25.73%,最大值为41.61%,平均值为34.12%。②植被在成熟收割时植被碳储量为5.18 t·hm-2,土壤碳储量84.74 t·hm-2。③花菜田土壤呼吸速率在生长初期最高,然后逐渐减弱,土壤异养呼吸通量为2.38 t·hm-2。④生育期内人工碳源总排放量为1.81 t·hm-2。⑤花菜1个生育期净固碳量为0.99 t·hm-2,相当于固定二氧化碳4.01 t·hm-2。崇明岛花菜田碳平衡测定结果为微弱碳汇,针对地区土壤盐碱化现状,当前最主要增汇减排措施是合理配施有机肥,改善土壤,增加产量从而增加碳汇,其次还可以农林间种,调整人员管理结构,减少碳源。

Carbon balance of Brassica oleracea var. botrytis from Chongming Ecological Agriculture Park in Shanghai

To contribute to measurement techniques for carbon sink additions and emission reductions，and to provide data to support the development of a low-carbon agricultural park，the carbon balance of Brassica oleracea var. botrytis was estimated. To evaluate carbon balance, the main carbon storage components of B. oleracea var. botrytis，soil respiration, and carbon sources of artificial management were determined by measuring biomass in an eco-agricultural area on Chongming Island in Shanghai. The main results showed that （1） the minimum carbon content of B. oleracea var. botrytis was 25.7%，the maximum was 41.6%, and the average was 34.1%. （2） At harvest, carbon storage of the vegetable layer was 5.18 t·hm^-2，and the soil layer was 84.74 t·hm^-2. （3） The respiration rate of the soil was highest in the initial stages of growth，and then gradually weakened. For one growing period, soil heterotrophic respiration effluxes for the B. oleracea var. botrytis farmland was 2.38 t·hm^-2. （4） Total carbon emission  was 1.81 t·hm^-2，and （5） net carbon sequestration in one growing period was 0.99 t·hm-2 fixing CO₂ 4.01 t ·hm^-2. Thus，to improve the weak carbon sink, reasonable fertilizer including organic fertilizer should be applied to increase production that will increase carbon sinks；as production increases, agroforestry intercropping and personnel management structure adjustments can be used to reduce the carbon source.［Ch，3 fig. 1 tab. 18 ref.］