Can the dormant seeding of rainfed lentil improve productivity and water use efficiency in arid and semi-arid conditions?

Dormant seeding (DS) has become popular in dry areas because it provides a longer growing season and optimum temperature during the early spring to grow crop. Long-term daily weather data for the period of 1984-2014, were collected for ten locations in northwestern Iran with a cold semi-arid and arid climate. The SSM-legumes model was used to investigate the effect of dormant seeding versus different fixed spring sowing dates as well as cultivars on the yield and water use efficiency (WUE) of lentil. The results showed that, the highest average grain yield across all the study locations was obtained for DS management and decreased around 49% when sowing date was delayed to 4 April. Furthermore, with a delay in sowing date, the decline in grain yield of short- cycle and long- cycle cultivars was 42% and 58%, respectively. On average, WUE for short- cycle cultivar was much higher than long-season cultivar (6.2 and 4.0 kg ha−1 mm−1, respectively). The combination of short-cycle cultivar × DS management resulted in 30% and 29% increase in grain yield and WUE, respectively when compared with a long-cycle cultivar × DS management. This conclusion was reached because DS sowing and short-cycle cultivar increased yield and its stability due to the proper establishment and appropriate growth conditions of lentil in late winter and early spring. DS also resulted in better use of precipitation and escape from the heat and drought stresses in late spring and early summer, provided that there is no frost risk in the target regions. Overall, the results of the simulations for all the study locations suggested that sowing lentil using DS is indeed superior over the other fixed spring sowing practices because it not only shortens the frost risk to seedlings but also provides optimal conditions for the growth and use of rainfall and soil moisture as well as lentil growth.