Potential Effects on the Quinoa Cultivation Yield Based on Different Hydric Scenarios of the Chilean Altiplano

This study evaluates the impact of different irrigation scenarios on the yield of quinoa (Chenopodium quinoa) in the Chilean Altiplano. The research was conducted in Ancovinto, Tarapacá, Chile, using “Pandela” quinoa seeds. Four irrigation treatments were implemented: rainfed (T0) and irrigation at 100% ETc (T1), 66% ETc (T2), and 33% ETc (T3). Various climatic variables, the soil moisture content, and agromorphological parameters were measured. The results indicated that rainfed conditions (T0) led to higher dry matter production in roots, stems, leaves, and panicles at the end of the growth cycle compared to irrigated treatments. The Leaf Area Index (LAI) was also higher in rainfed conditions during the flowering stage, demonstrating the crop’s adaptability to adverse water conditions. Additionally, the ability of quinoa plants under rainfed conditions to tolerate frost during critical growth stages was a key factor in their superior performance, contributing to a higher grain yield and harvest indices. Plants under rainfed conditions reached greater heights and showed higher harvest indices (HI) and grain yield than those under irrigation. The Water Use Efficiency (WUE) was significantly higher in rainfed conditions, suggesting more effective water utilization under water scarcity. This research represents a one-year study that provides orientations for future research, considering the interannual variability of precipitation in the region. The results obtained show that quinoa plants under traditional management (rainfed) exhibited the best response in the measured growth, development, and production variables, leading to higher production and harvest rates. Additionally, there was greater efficiency in water use, equivalent to 15.87 and 12.7 times that of the 100% and 33% ETc treatments, respectively. These findings highlight quinoa’s remarkable adaptability to harsh hydric conditions and the efficiency of traditional rainfed farming practices in the Altiplano.