Effect of Lodging on Evapotranspiration of Summer Maize at Milk Ripening Stage

Abstract

【Objective】 Strong winds in summer often result in lodging stress to summer maize in central China. The purpose of this paper is to evaluate experimentally how the lodging affects evapotranspiration from a maize field. 【Method】 The analysis was based on a dataset collected on 25 August 2016 after a strong wind hit Zhengzhou agrometeorological station. Using the Penman-Monteith (P-M) model, meteorological and crop data, as well as vorticity measured in 2017 (a normal year), we calculated the evapotranspiration and optimized the model parameters to fit the P-M model to the measured data in 2017. Using the P-M model and the calibrated parameters and field-survey data, we estimated evapotranspiration from the summer maize field without any lodging as the control (P-MN). The reduced evapotranspiration (P-ML) due to the lodging in 2016 was estimated using field survey-plant data. 【Result】 The evapotranspiration calculated without lodging agreed well with the measured data, with an absolute error of 0.005 mm/30 min, a relative error of 10.7%, and root mean square error and consistency index being 0.019 and 0.98 respectively. For the lodged maize field, the absolute and relative errors between the calculated and measured evapotranspiration were 0.002 mm/30 min and 2.9%, respectively, and the root mean square error and the consistency index were 0.001 and 0.98 respectively. 【Conclusion】 Mazie lodging at milk stage due to strong winds significantly reduced its evapotranspiration. Results calculated using the P-M model showed that the lodging reduced daily evapotranspiration by 0.68 mm, a 18.3% reduction compared to the control. The reduced daily average evapotranspiration in the early stage of the lodging was 20.6% (0.99 mm), while in the later stage it decreased to 0.42 mm, 14.8% down compared to the control.

Keywords

• summer maize
• lodging
• penman-monteith model
• eddy covariance
• simulation
• evapotranspiration