Effects of deficit irrigation and application of biofertilizers on the growing characteristics and water use efficiency on borage (Borago officinalis L.)

In order to study the effects of deficit irrigation and application of biofertilizers on the growing characteristics and water use efficiency (WUE) of Borago officinalis L. a field experiment was conducted in Kermanshah, Iran, in 2011. The experiment was carried out as split plot design with 3 replications. Deficit irrigation was the main factor with four levels, deficit irrigation in vegetative stage, reproductive­ stage, vegetative + reproductive stages and without deficit irrigation (control), which was applied by interrupting irrigation in the specific stages. Fertilizers incloded three levels, 100% chemical fertilizer, 50% of chemical fertilizer + biofertilizers, 25% chemical fertilizer + biofertilizers. Results indicated that treatments had significant effects on total dry weight, seed, oil percentage, harvest index and water use efficiency. Deficit irrigation on vegetative and reproductive level in comparison with full irrigation decreased 10% and 39% WUE of total dry weight and 13% and 21% WUE for grain. Among the fertilizer treatments, application of 50% of chemical fertilizer + Nitroxin and Biophosphate biofertilizers improved the mentioned criteria in the deficit irrigation condition. And the highest value of seed yield (108/1 kg/ha) was achieved by using 50% of chemical fertilizer + biofertilizers in no deficit irrigation. This treatment (50% + biofertilizers) in no deficit irrigation condition enhanced 26% total dry weight in comparison with utilizing 100% chemical fertilizers.