WATER-USE OF A WINTER-WHEAT CULTIVAR (TRITICUM-AESTIVUM)

A field trial with a winter wheat cultivar (Triticum aestivum) was conducted at the experimental field of the Introduction and Plant Resources Institute at Sadovo, Bulgaria, during 1982-83 and 1983-84. Three treatments, two irrigated and one non-irrigated, were used to determine the water use of winter wheat at the central-eastern region of Bulgaria. Irrigation was given to maintain two soil moisture regimes of 65-70-65% and 75-85-75% of field capacity during the periods emergence to jointing, jointing to flowering and flowering to dough stage, respectively. To maintain both the regimes irrigations were required in both the experimental years, but in different growth stages. Among the treatments the non-irrigated one showed the lowest peak evapotranspiration of 3.7 mm day-1 and the treatment irrigated at 75-85-75% of field capacity showed the highest peak of 5.8 mm day-1. The total water use under non-irrigated condition and irrigated at 75-85-75% of field capacity was 335 mm and 482 mm, respectively. Three irrigations during the post-winter period were required to maintain the latter moisture level, which used the highest amount of water among all the treatments. Both in irrigated and non-irrigated conditions 50% of the post-winter water use was contributed by the 0-20 cm root zone and no significance difference in soil moisture depletion along the deeper zones by the irrigated or non-irrigated treatments was observed.