اثر توامان تاریخ کشت و زمان تک آبیاری بر بهره وری آب عدس در شرایط دیم

supplementary irrigation is one of the most effective field management practices to improve water productivity and crop yield in rainfed conditions. time of supplementary irrigation is another important parameter affecting the enhancement of yield. in order to study the effect of supplementary irrigation time as well as planting date, two factors, namely: 1) supplementary irrigation (no irrigation as control (t1), single irrigation at grain filling stage (t2), and single irrigation at pod filling stage (t3)); 2) planting date (planting on april 4 (d1) vs. 14 (d2)) were considered and a field experiment carried out at the research and training farm of imam khomeini international university, qazvin, iran in spring 2011. the field experimental design was a factorial one based upon rcbd of six treatments and three replications. treatments consisted of: d1t1 (planting date on 4th april – without irrigation as control), d1t2 (planting date on 4th april – single irrigation at grain filling stage), d1t3 (planting date on 4th april – single irrigation at pod filling stage), d2t1 (planting date on 14th april – non-irrigated), d2t2 (planting date on 14th april – single irrigation at grain filling stage), d2t3 (planting date on 14th april – single irrigation at pod filling stage). the effect of single irrigation time on yield, biomass and number of grains in unit area was significant as planting on 4th april and single irrigation at grain filling stage resulted 280 and 210 percent increase in yield and in biomass respectively, as compared to single irrigation at pod filling stage. the planting date factor showed a significant effect on yield and yield components as the yield decreased from 1057.6 (kg/ha) for a single irrigation at grain filling stage and planting on 4th april to 190.93 (kg/ha) for a single irrigation at the same stage and planting on 14th april. this means that the delay in planting date caused a reduction of 82 percent in yield for a single irrigation at grain filling stage. this reduction for single irrigation at pod filling was equal to 82 percent and the amount of yield decreased from 371.6 (kg/ha) for planting on 4th april to 68.2 (kg/ha) for planting date of 14th april.