Winter wheat canopy interception and its influence factors under sprinkler irrigation Yaohu Kang * , Qing-Gai Wang, Hai-Jun Liu Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Anwai, Beijing 100101, China Accepted 29 November 2004 Abstract Field studies on winter wheat canopy interception with its relations to leaf area index (LAI), plant height, drop diameter, wind speed, and water application intensity were carried out. Canopy interception was measured using the water wiping method. Results indicate that the maximum value of winter wheat canopy interception was not more than 1.0 mm, much smaller than presented by previous investigators. The total canopy interception for the growing season was 2.4 mm, only 1.3% of the total irrigation amount (194.6 mm), for four sprinkler irrigation events during 2003. Canopy interception increased as leaf area index and plant height increased. A linear regression model was developed to express the relationship of canopy interception with leaf area index and plant height. There was good agreement between the values of canopy interception measured using the water wiping method and estimated using the linear regression model. Results also indicate that canopy interception decreased as drop diameter and wind speed increased. An exponential relation- ship was found between canopy interception and drop size, and a linear relationship between canopy interception and the square of the wind speed. Water application intensity does not affect canopy interception significantly. # 2004 Elsevier B.V. All rights reserved. Keywords: Canopy interception; Influence factors; Winter wheat www.elsevier.com/locate/agwat Agricultural Water Management 74 (2005) 189–199 * Corresponding author. Tel.: +86 10 64856516; fax: +86 10 64856516. E-mail address: kangyh@igsnrr.ac.cn (Y. Kang). 0378-3774/$ – see front matter # 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.agwat.2004.11.004