The Effect of Irrigation by Saline Water on Lentil Yield, Compared to Non-Saline Rainfed Cultivation Conditions (in Qazvin)

This research was conducted on lentil at Imam Khomeini international university in 2021. The treatments were included of rainfed (D) and five salinity levels of irrigation water with EC of 0.5 (S0), 2 (S1), 4 (S2), 6 (S3) and 8 (S4) dS.m-1. The experiment was performed in a randomized complete block design with three replications. In treatments of D, S0, S1, S2, S3 and S4, some parameters were measured; the biomass yields equal to 2094.66, 3621.9, 3525.6, 2771.6, 1965.62 and 1120.6 kg.h-1, the grain yield equal to 399.25, 957.53, 932.07, 639.25, 279.33 and 46.82 kg.ha-1 and the straw yield equal to 1695.41, 2664.37, 2593.53, 2132.35, 1686.29 and 1073.78 kg.ha-1,  respectively. The results showed that the use of water up to S2 salinity level was recommended for lentil cultivation. But higher salinity levels were reduced the yield relative to rainfed conditions. At the water salinity threshold of 5.5, 5.3 and 5.6 dS.m-1, the amounts of biomass, grain and straw were equal to rainfed conditions. Due to salinity stress, the relative yield (compared to rainfed) of biomass, grain and straw were decreased with a slope of 0.166, 0.325 and 0.129, respectively. As a result, the grain yield was more sensitive than the straw yield in terms of water salinity. The reason was the effect of salinity stress on plants pollination and lack of grain filling. The amount of water use efficiency (for production of lentil dry biomass) was calculated in treatments of D, S0, S1, S2, S3 and S4 which were equal to 3.55, 1.32, 1.3, 1.23, 1.11 and 0.97 kg.m-3, respectively. In general, the results showed the application feasibility of saline water (in the range of crop tolerance) for irrigation to increase the lentil yield (compared to rainfed conditions). In these conditions, the saline water resources of the region can be exploited.