Field evaluation of potassium and humic acid rates for enhancing garlic yield under alkaline soil and limited irrigation

Combined alkalinity and water stress can disrupt nutrient distribution among plant organs and consequently affect crop productivity, yet the temporal patterns of nutrient distribution under these simultaneous stresses remain insufficiently characterized in garlic. Therefore, this study aimed to determine how potassium (K) and humic acid (H) applications affect nutrient allocation patterns, yield, and water use efficiency of garlic grown in alkaline soil under full and deficit irrigation. In the seasons of 2022/23 and 2023/24, a field experiment was conducted to evaluate the impacts of different rates of K and H on nutrient allocation patterns, yield, and water use efficiency of garlic plants grown in alkaline soil and irrigated with two irrigation levels at 100% and 70% of crop evapotranspiration (ETc). Nutrient allocation was evaluated from the measured distribution of nitrogen, phosphorus, K, sulfur, zinc, calcium, magnesium, and sodium between garlic leaves and bulbs at the investigated sampling times. The results showed that irrigation level and K and H applications modified nutrient allocation patterns differently between the short- and long-term sampling periods. These findings indicate temporal changes in nutrient distribution among garlic organs rather than directly demonstrating active nutrient reallocation. The treatment of 150 kg K2O ha−1 + 20 kg H ha−1 under 70% of ETc produced the highest garlic yield and water use efficiency among the tested treatments. Overall, the combined K and H application modified nutrient distribution under deficit irrigation and was associated with improved productivity and water use efficiency.