Assessments of saline water application and different irrigation intervals on soil and soybean yield
The global water crisis reminds the important of enhancing water productivity in agriculture to increase the crop production and food security. Declining availability of fresh water resources has become a worldwide problem which promotes the new alternative sources of water-supply to overcome to this issue. In this goal, the effects of different irrigation intervals and water quality on soybean growth and soil properties were investigated by a field split plot experiment in a randomized completely block design water in three replications. Different saline water levels (1, 4 and 7 dS m-1) and three irrigation intervals (7, 10 and 13 days) were arranged as studied factors in main and subplot, respectively. The maximum performance was obtained by the treatment of 7 days irrigation interval+non-saline water which produced 3760 and 8355 kg ha-1 grain yield and biomass, respectively. Also, maximum water use efficiency of 9.08 kg ha-1mm-1 was obtained by 13 days irrigation interval+7 dS m-1 salinity. Maximum soil salinity (ECe) in different soil layers was observed in the highest irrigation saline water treatment (7 dS m-1) in all irrigation intervals. Moreover, irrigation with highest salinity level (S3) resulted in the salt accumulation in the root zone from 1.4 dS m-1 (before sowing) up to 5.7 dS m-1 at the end of growing period. Therefore, based on soil salinity and crop yield, irrigation interval 7 days at lower levels of irrigation water salinities (up to 4 dS m-1) is suitable for soybean production in the semi-arid environment.
Keywords: Interval irrigation, Salinity, Soybean, Sustainability, Water use efficiency