黄淮海平原典型冬小麦农田生态系统能量平衡研究—以封丘地区为例

Research on energy balance of the typical winter wheat farmland ecosystem in the Huanghuaihai plain: A case study in Fengqiu region

本文以位于黄淮海平原的中科院封丘农业生态试验站冬小麦农田生态系统为研究对象,基于2013年10月至2014年6月涡度相关和自动气象站观测资料,利用涡度相关法和相关性分析法对黄淮海平原典型冬小麦各生育期的能量平衡特征进行了分析,揭示冬小麦农田环境气象要素与各分支通量之间的相关关系。结果表明:黄淮海平原典型冬小麦各生育期能量分配的特征不同,出苗期潜热仅占净辐射的40%,拔节期和抽穗期潜热占净辐射的比重均高达80%以上,其他生育期潜热占净辐射的比重均为55%以上。播种期和出苗期显热通量占净辐射的比重最大,均可达50%以上;分蘖期及其后生育期显热通量占净辐射的比重均为35%及以下,拔节期和抽穗期显热通量占净辐射的比重最小,仅为10%左右;随着冬小麦的生长,显热通量占净辐射的比重基本呈下降的趋势。冬小麦各生育期土壤热通量的区别不明显,越冬期土壤热通量占净辐射的比例为15%,其余各生育期土壤热通量占总能量的比例均为10%以下。冬小麦各生育期的能量闭和度均较高,出苗期能量闭合度为83%,分蘖期能量闭合度为90%,返青期以后生育期的能量闭合度均为90%及以上。2013—2014年封丘地区冬小麦各生育期气温与各通量之间呈正相关关系,相对湿度与各通量之间呈负相关关系;冬小麦生育期土壤温度与土壤热通量之间的相关系数为0.5左右,土壤温度与净辐射、潜热、显热之间无显著相关性;土壤含水量在冬小麦播种期、返青期与各通量的相关系数均为-0.5,其他生育期土壤含水量与各通量无明显相关性。

A winter wheat farmland ecological system located at the Feng-Qiu agricultural ecological experimental station of the Chinese academy of sciences in the Huanghuaihai（ Huanghe,Huaihe,and Haihe rivers） plain was selected as the test object in this paper. Using the data observed by the eddy covariance system and the automatic meteorological stations from October 2013 to June 2014,the energy balance at each growth stage of the typical winter wheat in the Huanghuaihai plain was analyzed based on eddy correlation and correlation analysis methods.The main purpose of this study is to find the relationships between each flux and the environment meteorological factors in the farmland. The results showthat the energy partitioning feature at each growth stage is different for the winter wheat. The percentage of latent heat to the net radiation at the seedling period is only 40%,while for the periods of jointing and heading,it is more than 80%,and for the other periods,it is also more than 55%. The percentage of sensible heat to the net radiation decreases with growth,reaching 50% at the sowing and seedling periods,and below35% at tillering and the following periods,until jointing and heading periods with only 10%. During the whole growth period,the percentage of soil heat flux to the net radiation is stable,with 15% overwintering period and less than 10% at the other periods. The energy closed degree is high,with 83% at the seedling period,90% at the tillering period,and more than 90% after returning green period. There is a positive correlation between air temperature and each flux,and a negative correlation between relative humidity and each flux. The correlation coefficient between soil temperature and soil heat flux is about 0. 5. There are no significant correlations between soil temperature and net radiation,latent and sensible heat fluxes. The correlation coefficients of soil water content with each flux at sowing and returning green periods are 0. 5,and for the other growth stages,this kind of significant correlation is not found.