摘要
利用热脉冲茎流计监测西北旱区盛果期苹果树茎干液流变化规律,采用自动气象站测定气象因素的变化,在试验基础上分析了苹果树液流量的动态变化并分别采用基于冠层变化的季节蒸发蒸腾模型(Cj)、双作物系数模型(Kcb)和Priestley-Taylor模型对日均蒸腾量进行模拟。研究结果表明,日均茎干液流量呈先增加后降低的单峰曲线,基于冠层变化的季节蒸发蒸腾模型可以准确估算西北旱区盛果期果树的日均蒸腾量,模拟的日均蒸腾量可以减小液流量的时滞影响,提高长时间估算果树蒸腾量的精度。
Sap flow is a key character in the understanding of plant hydraulic functioning and it is crucial in determining water consumption research of agriculture in Northwest China. The field experiment was conducted during 2008—2010 at the Shiyanghe Experimental Station for Water-Saving in Agriculture and Ecology. The site has a continental temperate climate with mean annual sunshine duration of more than3 000 h,mean annual temperature of 8℃ and mean annual precipitation of 164 mm. Apple trees（ Malusdomestica Borkh. cv. Golden Delicious） were planted in 1981,with row spacing of 6 m and plant spacing of 4 m. The experimental plots were irrigated four times per year by flood irrigation to avoid tree water stress. After measuring trunk sap flow using heat pulse method and wind speed,net radiation,relative humidity,air temperature with an automatic meteorological station,the seasonal variation of sap flow was analyzed and the daily transpiration was modeled using seasonal evapotranspiration model by canopy gap distribution（ Cj）,dual crop coefficient method（ Kcb） and Priestley-Taylor method（ PT）.The Cj model combined hourly changes in canopy gap fraction to calculate the cover ratio of soil under the canopy and bare soil outside the canopy for soil evaporation,which was constant in the clumping model.Results showed that the seasonal sap flow increased at the beginning of the growing stages and reached peak value of 6. 5 mm / d in mid-June. The Cj model performed well in modeling daily transpiration.Compared with the trunk sap flow,the average transpiration,determination coefficient（ R2）,mean absolute error（ MAE） and Nash and Sutcliffe modeling efficiency（ NSE） of Cj model were 2. 51 mm / d,0. 49,0. 93 mm / d and 0. 01,respectively. The Cj model and PT model were better in the leaf expanding period than in fruit expanding period for transpiration modeling,while the Kcbmodel kept stable during the whole season. The Cj model could decrease the effect of time lag of sap flow and be used for long
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2016年第2期105-112,共8页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51309132
51509130)
江苏省基础研究计划青年基金项目(BK20130995
BK20150908)
中央高校基本科研业务费专项资金项目(26120132013B06014)
