Productive and non-productive use of water of common bean under full and deficit irrigation

Abstract

This paper investigates water productivity (WP g m-2), water use efficiency (WUE kg m-3) and productive and nonproductive water of common bean (Phaseolus vulgaris L.). The experiment was set up in Stara Pazova, 40 km north of Belgrade, during 2018. Three treatments of irrigation regimes, with tree sowing periods (I – April 16, II – May 30, III – July 5) were monitored. A treatment with full irrigation (F), when 100% is covered by ETc (evapotranspiration), a treatment with deficit irrigation (R) with 80% of the ETc and a treatment with deficit irrigation (S) with 60% of ETc were applied in each sowing period. An automatic weather station was set up adjacent to the experimental plots. Reference evapotranspiration (ETo) was estimated with the FAO Penman-Monteith equation using daily data obtained from the station. Crop evapotranspiration (ETc) was calculated as the product of ETo and the dual crop coefficient. The WP values were uniform in all treatments in the I sowing period (15.66-15.82 g-2), whereas WUE values ranged from 1.31 kg m-3 (S) to 1.64 kg m-3 (F). In the II sowing period, the WP and WUE varied most, and were the highest in the F treatment (15.54 g-2, 1.58 kg m-3), slightly lower in the R treatment (13.92 g-2, 1.40 kg m-3), and the lowest values were recorded in the S treatment (12.52 g-2, 1.25 kg m-3). In the III sowing period, the highest WP and WUE were in the R treatment (12.24 g-2, 1.57 kg m-3), followed by the F treatment (14.12 g-2, 1.43 kg m-3), whereas the lowest values were observed in the S treatment (13.72 g-2, 1.27 kg m-3). The least unproductive water use was observed in the fully irrigated treatment during the I sowing period (13.46%) and the highest one in III treatment (26.30%).