Determination of the effects of different lateral depth in subsurface drip irrigation system on bioethanol production together with growth of sorghum plant and simulation of moisture distribution in the soil profile with hydrus/2D model

In this study, it was aimed to evaluate the effects of different lateral depths and irrigation water levels on the yield and plant growth parameters of the sorghum plant in the subsurface drip irrigation method and to determine the most appropriate lateral depth and amount of irrigation water in subsurface drip irrigation on the sorghum plant with the HYDRUS/2D model. The experiment was carried out in three replications in a randomized block trial design between 2020-2021 in Antalya. In irrigation treatments, three different irrigation water levels (S100, S66, S33, respectively) in which 100%, 66% and 33% of the amount were applied as irrigation water, when the cumulative reference crop evapotranspiration reached 25±5 mm and lateral depth combinations in which the laterals were placed at two different depths, 25 cm and 50 cm (D25 and D50, respectively) were used. It was determined that lateral depth and, the interaction of lateral depth and irrigation level did not affect the bioethanol yield values in both growing seasons. On the other hand, a statistical difference (p<0.01) was determined between the average bioethanol yield values of different irrigation levels. It was concluded that the bioethanol yield decreased as the applied irrigation level decreased. While the highest bioethanol yield was determined in S100 at the end of both growing seasons, no difference was found between S66 and S100 subjects in the second growing season. In general, although it was determined that lateral depth, the interaction of lateral depth and irrigation water level did not affect the growth parameters of sorghum plant in both growing seasons, it was concluded that plant growth parameters were better at 50 cm lateral depth. The R2 values determined for the estimated and measured soil water content using the HYDRUS/2D model ranged from 0.49-0.92, RMSE values between 16.76-70.50 mm and MAE values between 16.18-66.36 mm. Obtained results showed that HYDRUS/2D program is a successful model for estimating soil water content. In the scenarios prepared, the most suitable wetting pattern and the change in soil water content during the period were obtained from the S66 topic at 40 cm lateral depth and from the S100 topic at configurations using two different lateral depths (25 and 50 cm) where the irrigation water amount was applied equally.