Interactive Effect of Irrigation and Sowing Methods on Yield, Quality, and Water Productivity of Quinoa under Ridge Sowing Technique

This study aims to secure the production of quinoa under arid conditions. We believe that sowing methods and irrigation availability may impact the productivity of quinoa in semiarid ecosystems. A two-year (2019 and 2020) study was planned using line-source sprinklers to evaluate the effect of irrigation and sowing methods on quinoa in the Eastern Mediterranean zone of Turkey. The main plots and subplots comprised three sowing methods (single row (Sr), double row (Dr), and triple row (Tr)) and three irrigation (full irrigation: IL_1.0; deficit irrigation: IL_0.5, and rainfed: IL_0.0 treatments), respectively. The highest quinoa yields were produced from full irrigation. The yield response factor (ky) was 1.08–1.34 in Sr, 0.99–1.10 in Dr, and 0.82–1.07 in Tr sowing methods in two consecutive trial years. The oil percentage decreased with increasing irrigation in both years. Protein, ash, oil percentage, and fiber contents decreased with increasing irrigation water in each sowing method, but evapotranspiration (ETa), leaf area index (LAI), plant height, and thousand-seed weight increased in both years. Reducing irrigation levels and increasing sowing rows generally increased soil-borne disease emergence. TrIL_1.0 treatment achieved the highest net income in the combined two-year economic appraisal. It is suggested that using the triple sowing row with deficit irrigation significantly improves the seed and oil yield, quality, water use efficiency (WUE), and irrigation water use efficiency (IWUE) under the ridge sowing technique in semi-arid zones. TrIL_0.5 can be recommended as an alternative for regions where irrigation water is limited and costly.