摘要
作物系数是计算作物蒸散量的关键参数。利用2006-2008年和2011年辽宁锦州玉米农田生态系统的涡度相关、气象、作物发育期及叶面积指数观测数据,分析不受水分胁迫条件下玉米逐日作物系数特征及其与叶面积指数的关系。研究表明:作物系数与玉米农田实际蒸散均呈单峰型变化,约在7月末至8月初达到最大值(玉米开花吐丝期)。在此基础上,建立了不受水分胁迫条件下玉米逐日作物系数与叶面积指数关系(达到0.01显著性水平),同时,采用积温表示的标准化生育期方法模拟相对叶面积指数,并建立了逐日作物系数与相对叶面积指数关系(达到0.01显著性水平),解决了无叶面积观测地区玉米逐日实际蒸散量的计算。研究结果可为玉米农田用水管理以及灌溉措施的制定提供参考。
Spring maize is one of the most important crops in Northeast China and accounts for about 1/3 of grain crop area.Due to climate change in Northeast China during recent years,climate warming and drying trend is very significant.As a result,drought disasters of spring maize occur frequently,moreover,it often occurs in the critical period of the formation of maize production,resulting in a serious impact on maize yield.How to scientifically irrigate maize farmland and ensure maize yield stable and high is a serious challenge.In order to accurately calculate the actual evapotranspiration of maize,dynamic daily crop coefficient of spring maize and its relationship with leaf area index are studied,using the latent heat flux data from eddy covariance(EC),and corresponding data including meteorological data,phenological data and leaf area data during 2006- 2008 and 2011 at Jinzhou Agricultural Ecosystem Research Station.Results indicate that both daily crop coefficient and actual evapotranspiration of spring maize farmland ecosystem show a unimodal curve change,and they reach the maximum from late July to early August(maize flowering and silk stages).A new dynamic crop coefficient model under conditions of enough water supply is developed for spring maize,and it indicates the close linear relationship between crop coefficient and leaf area index(R^2 = 0.88,F=73.5,P<0.01).Furthermore,the relative leaf area index is simulated using the standardization of growth period based on cumulative temperature.The relationship between daily crop coefficient of spring maize and relative leaf area index are also developed(R^2=0.93,F=527,P-<0.01),which solves the calculation of daily actual evapotranspiration over spring maize farmland ecosystems without the leaf area observation.This new model improves the crop coefficient suggested by FAO,and extends the calculation from phonological stages to daily scale.At present,crop coefficients come from different evapotranspiration observation methods,including lysimeter and eddy covariance,and different methods lead to significantly different results.The comparison shows that crop coefficients of maize at four phenological stages based on the evapotranspiration observations from eddy covariance towers are the closest to values suggested by FAO.The newly developed crop coefficient model is able to simulate daily actual evapotranspiration of spring maize farmland ecosystem with a good accuracy.It could provide theoretical basis for the management of agricultural water resources and irrigation.
出处
《应用气象学报》
CSCD
北大核心
2015年第6期695-704,共10页
Journal of Applied Meteorological Science
基金
国家自然科学基金重点项目(41330531)
中央级公益性科研院所基本科研业务费专项(2015IAE-CMA05)
关键词
春玉米
逐日作物系数
涡度相关法
spring maize
daily crop coefficient
eddy covariance method
