农田生态系统是陆地生态系统的重要组成部分，玉米是我国种植面积和产量最大的粮食作物。在气候变化背景下，准确评价夏玉米农田生态系统的碳源汇特征，对提高农田生态系统固碳能力具有重要意义。利用1991-2022年郑州国家基本气象站气象数据和2008-2022年郑州农业气象试验站夏玉米农田生态系统CO2通量数据、气象观测数据及夏玉米生物量和产量数据，分析了郑州站气候变化特征以及夏玉米农田生态系统CO2通量变化规律，明确了夏玉米农田生态系统碳源汇特征。结果表明:夏玉米农田生态系统CO2通量具有明显的日变化和季节变化特征，除6月份为碳源外，7-9月份均为碳汇。不同气候年型下，夏玉米农田生态系统碳通量具有一定的差异，总初级生产力(gross primary productivity，GPP)多年平均值为1197。5±129。9gC·m-2·a-1;生态系统呼吸(Reco)多年平均值为711。2±129。9 g C·m-2·a-1。不计算收获后的籽粒，夏玉米农田整体表现为CO2的汇，净生态系统碳交换量(net ecosystem exchange，NEE)多年平均值为-342。8±52。3 g C·m-2·a-1。籽粒收获移出农田后，根据理论产量计算，夏玉米农田表现为弱的碳汇，净生物群系生产力(net biome productivity，NBP)为-41。3 g C·m-2·a-1(占 NEE 的 12。0％);根据实际产量计算，夏玉米农田在籽粒收获后表现为较强的碳汇，NBP为-105。9 g C·m-2·a-1(占NEE的30。9％)。郑州站气候呈现暖干化变化趋势，气温和降水对夏玉米农田生态系统碳通量无显著影响，日照时数对夏玉米农田生态系统GPP影响显著(P＜0。05)，并通过GPP对净生态系统生产力(net ecosystem productivity，NEP)和Reco产生间接影响(P＜0。05)。夏玉米生长季，日照时数增加15。6 h·a-1，GPP增加19。4 g C·m-2·a1，NEP增加6。6 g C·m-2·a-1，表明夏玉米农田生态系统具有较大的固碳潜力。
Carbon source and sink characteristics and climate impacts of summer maize cropland ecosystem
Cropland is an important type of terrestrial ecosystem.Maize is the grain crop with the largest planting area and production in China.In the context of climate change,accurately evaluating the carbon source and sink characteristics of summer maize cropland is of great significance to improving cropland carbon sequestration capaci-ty.In this study,we collected the meteorological data during 1991-2022 from Zhengzhou National Basic Meteoro-logical Station and the data of CO2 flux,meteorological factors,and biomass and yield of summer maize during 2008-2022 from Zhengzhou Agrometeorology Experiment Station.Based on these data,we analyzed the change characteristics of climate variables and CO2 flux and the carbon source and sink characteristics of summer maize cropland.The results showed that there were obvious daily and seasonal change characteristics of CO2 flux of sum-mer maize cropland ecosystem.It was a carbon sink from July to September but a carbon source in June.The CO2 flux of summer maize cropland was different under different climate year types.The annual average of gross primary productivity(GPP)and ecosystem respiration(Reco)of summer maize cropland was 1197.5±129.9 g C·m-2·a-1 and 711.2±129.9 g C·m-2·a-1,respectively.Without including grains after harvest,summer maize cropland ecosystem was a carbon sink,with multi-year mean value of net ecosystem exchange(NEE)being-342.8±52.3 g C·m-2·a-1.After the grains were harvested and removed from the cropland,summer maize cropland exhibited a weak carbon sink,with a net biome productivity(NBP)of-41.3 g C·m-2·a-1(12.0％of NEE)based on calcu-lated theoretical yield.Based on actual yield,summer maize cropland exhibited a strong carbon sink,with a NBP of-105.9 g C·m-2·a-1(30.9％of NEE).The climate in this area showed a warm-dry tendency.Temperature and precipitation did not affect C02 flux of summer maize cropland ecosystem.In contrast,sunshine duration had a sig-nificant impact on GPP of summer maize cropland ecosystem(P＜0.05),and indirectly affected net ecosystem pro-ductivity(NEP)and Reco through GPP(P＜0.05).In the summer maize growing season,GPP and NPP increased by 19.4 g C·m-2·a-1 and 6.6 g C·m-2·a-1 respectively when sunshine duration increased by 15.6 h·a-1.Our results indicate that summer maize cropland ecosystem has a large carbon sequestration potential.
万方数据
维普
