Nitrogen and molybdenum fertilization influence on enzymatic activity and productivity enhancement of forage sorghum under water deficit in the Brazilian semi-arid region

Abstract

Water scarcity, combined with low soil fertility, constitutes one of the main limiting factors in crop productivity in semi-arid regions. However, nutritional supplementation techniques with nitrogen (N) and molybdenum (Mo) can lead to positive enhancements in the production of these crops. The objective was to evaluate the effect of increasing doses of N in the presence and/or absence of Mo on the activity of antioxidant enzymes and the productive increase of forage sorghum subjected to water deficit in the semi-arid region. The experiment was conducted in the field using a randomized block design, with four replications, in a 5 × 2 × 3 factorial scheme, comprising five doses of N (urea): 0, 50, 100, 150, and 300 kg ha−1, two doses of Mo (sodium molybdate): 0 and 160 g ha−1, and three production cycles. The highest yields of green mass (GM) (47.98 Mg ha−1), dry mass (DM) (19.66 Mg ha−1), water use efficiency (WUE) (5.57 kg/m³), and N use efficiency (NUE) (0.26 kg2/g) occurred at the highest N dosage (300 kg ha−1 N). The highest contents and extraction of total N, Mo, chloride (Cl), and potassium (K) were found in regrowth 2 and at the highest N dose (300 kg ha−1). The interaction of N and Mo resulted in higher catalase (CAT) enzyme activity. The meteorological conditions during the cycles strongly influenced the nutrient contents and extraction. The results of the study provide support for producers to use N and Mo fertilization strategies to improve crop productivity, even under water deficit conditions.