The effect of irrigation levels and different tillage systems on grain sorghum yield

In order to study the effect of different tillage systems and irrigation levels on corn yield, an experiment was conducted as split plot in the form of randomized complete blocks with three replications in the research farm of the University of Tehran in 2016. The main factor in this experiment was tillage with two levels (no tillage and conventional tillage) and the secondary factor was irrigation levels with three levels (without water stress, moderate water stress and severe water stress based on 75, 110 and 150 mm evaporation from Evaporation pan surface, respectively) was considered. The results showed that the effect of tillage on grain yield and water use efficiency was significant at 1 and 5% probability level, respectively. Also, the effect of irrigation levels on plant height, grain number per panicle, grain yield, biological yield and water use efficiency was significant at 1% probability level and on 1000-grain weight at 5% probability level. Maximum plant height(100.38 cm), number of seeds per panicle (2408), 1000-seed weight (31.33 gr), grain yield (5843 kg.ha-1),and biological yield (11575 kg.ha-1) was obtained from irrigation based on no water stress treatment (75 mm evaporation from the surface of the evaporation pan) and the maximum water use efficiency (1.15 kg.m-3) was found from severe drought stress (150 mm evaporation from the surface of the evaporation pan). Also, no tillage method increased grain yield (16.25%) and water use efficiency (13.72%) compared to conventional tillage method.