Yield and bioethanol productivity of sorghum under surface and subsurface drip irrigation

Abstract

The objective of the present study was to determine the effects of different irrigation levels applied with surface drip irrigation (SDI) and subsurface drip irrigation (SSDI) method on yield and bioethanol productivity of sorghum (Sorghum bicolor L. cv. Early Sumac) in the West Mediterranean Region of Turkey. Field study was conducted in Batı Akdeniz Agricultural Research Institute in Antalya during the growing seasons of 2017−2018. Five different irrigation levels designated as full irrigation (I100) with no water stress and slight (I75), mild (I50), severe water stress (I25) and no irrigation (I0) treatments were applied. The results showed that different irrigation levels applied had statistically significant effect on yield and yield components such as plant height, leaf number, leaf area index, chlorophyll context, brix, sucrose, glucose, fructose and bioethanol. In both of the drip irrigation methods, water deficit stress significantly (P ≤ 0.01) decreased bioethanol yield. The maximum bioethanol yield was obtained from SSDI method under full irrigation, slight, mild, severe and full water deficit stress as much as 2085, 2045, 1684, 1569 and 1407 L ha−1, respectively, in 2017 and 2390, 2266, 1954, 1901 and 1493 L ha−1, respectively, in 2018. The highest water consumption was observed in I100 treatment as 553.6 mm for SDI in 2017, while the lowest was found in I0 treatment as 198.5 mm for SDI in 2018. The highest water productivity was found in I0 as 6.0 kg ha−1 mm-1 for SSDI method in 2018, and the lowest one was found in I25 as 2.9 kg ha−1 mm−1 for SDI in 2017. The results of the present study showed that an average water saving of 24.0 mm compared with the SDI method was achieved without any decrease in efficiency in the SSDI method.