Alternate use of fresh and saline waters to improve water productivity and soil sustainability of drip irrigated wheat in a semi-arid region

Abstract

Severe problems of rising groundwater and secondary soil salinization demand holistic agricultural water management in canal command areas. Drip irrigation with alternate use of fresh and saline waters is an excellent irrigation approach to mitigate salinity stress caused by highly saline ground water and also to avoid soil sodicity hazards from canal water. Therefore, a study on cyclic mode conjunctive use of good quality surface water (SW) and highly saline ground water (GW) having average electric conductivity 0.3 and 7.6 dS m−1, respectively was carried out in wheat with five treatments of drip viz. 1SW1GW (1:1 :: SW:GW), 1SW2GW (1:2 :: SW:GW), 2SW1GW (2:1 :: SW:GW), SW (all SW), GW (all GW), and one treatment of conventional border ­irrigation method (BI). Highest grain yield was observed in SW (2.99 t ha−1) in 2017–2018 and BI (3.83 t ha−1) in 2018–2019 season. However, yield of SW and BI were statistically at par in both seasons. Grain yield of 1SW1GW, in which only 50% freshwater was used was found statistically at par with SW and BI. Physical Water Productivity was highest for SW, amounting 9.34 and 14.13 kg ha−1.mm−1 during 2017–2018 and 2018–2019, respectively. Soil salinity build up was highest for GW and lowest for SW, whereas it was almost similar for BI and 1SW1GW. Thus, 1SW1GW showed added benefits as its grain yield was statistically at par with SW and BI along with 50% fresh water saving over SW and higher water productivity than BI for similar salinity levels.