Possibilities of using dual K c approach in predicting crop evapotranspiration of second-crop silage maize

Authors : Neşe ÜZEN, Öner ÇETİN, Ramazan YOLCU

Pages : 272-280

View : 13 | Download : 9

Publication Date : 2018-08-01

Article Type : Research Paper

Abstract :The purposes of this study were to develop a dual crop coefficient insert ignore into journalissuearticles values(K c ); using FAO-56 methodologies and to compare crop evapotranspiration insert ignore into journalissuearticles values(ETK c ); measured under field conditions for second-crop silage maize in the Southeastern Anatolia Region of Turkey with the ET c estimated using FAO-56 dual K c methodologies. For this study, field experiments were conducted in the 2011 and 2012 growing seasons, and the results were evaluated. To compute dual K c insert ignore into journalissuearticles values(K cb and K e );, all climatological data involving the seedling and harvesting dates, growth stages, water holding of soil at field capacity and at wilting point, soil evaporation layer, and crop characteristics were input into a spreadsheet program. The crop stages observed were 15, 25, 40, and 12 days for the initial, crop development, midseason, and late-season stages, respectively, in 2011, and 12, 23, 43, and 13 days, respectively, for the same stages in 2012. The reference evapotranspiration insert ignore into journalissuearticles values(ET o ); was computed daily using the Penman-Monteith equation. All main and intermediate calculations for the dual Kc and its components K cb and K e were based on the FAO-56 guidelines. The K cb values were computed as 0.15, 1.27, and 0.62 for the initial, midseason, and late-season stages, respectively. However, these figures were 0.15, 1.15, and 0.5 in the FAO-56 in the same order. The dual K c was 0.64, 1.27, and 0.67 in this study for the initial, midseason, and late-season stages, respectively. The maximum ET c rate occurred in midseason, which had an average maximum value of 10.8 mm day -1 . The ET c of silage maize for optimal dry matter during the growing season in the years of the study was 519 mm as the average of two growing seasons. The FAO methodology thus insignificantly overestimated the seasonal ET c insert ignore into journalissuearticles values(536 mm); for silage maize. Thus, the FAO-56 dual K c methodology can be used to estimate the crop ET c .
Keywords : Crop evapotranspiration, drip irrigation, dual K c, silage maize