Published in Scientific Papers. Series A. Agronomy, Vol. LXIII, Issue 1
Written by Nadya HRISTOVA, Aleksander MATEV, Rossitza MERANZOVA, Konstantin DIMOV
The aim of the research is establishment of soil moisture level influences on the evapotranspiration (ET) and water use efficiency (WUE) of soybean. The field experiment was conducted in period 2009-2010. Three treatments were applied: T1 without irrigation, T2 irrigation at 80% of field capacity for the soil layer 0-0.6 m, T3 irrigation at 90% of field capacity. Evapotranspiration of soybean under rain-fed conditions is 272 mm. In irrigation regime T2ET increases by 50% and in irrigation regime T3 - by 63%, respectively 407 and 443 mm. The maximum ET daily values were observed during period of flowering and bean forming. During the same period 48-49% of ET is formed, irrespective of irrigation regime. Soybean consumes the most intense water from the layer 0-0.2 m (more than 20%). The total irrigation rate provides 50-52% for ET of T2 and 55-56% for T3. Water use efficiency is higher at lower soil moisture (80% of FC) - 1.843 kg/m3, while at 90% of FC WUE is 1.856 kg/m3. It is recommends irrigation, when soil moisture drops to 80% of the field capacity.
[Read full article] [Citation]
