Assessment of leaf nutrient and fertility norms for sweet orange under black soil in Nagpur district, Maharashtra, India

An investigation entitled "Assessment of leaf nutrient and fertility norms for sweet orange under black soil in Nagpur district, Maharashtra, India" was conducted during 2023-24 to evaluate the soil and leaf nutrient status in black soils. 27 soil and plant samples (0-30 cm) from 6 to 8 year old orchards were analyzed. Soil samples were tested for fertility status, while leaf samples were assessed for nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron, manganese, zinc, copper, and boron content. Fruit yield and quality parameters were recorded in November 2023. Soil properties varied with pH ranging from 7.02 to 8.00, EC from 0.150 to 0.294 dS m-1, OC from 4.30 to 5.80 g kg-1, and CaCO3 from 2.2 to 4.2%. Macronutrient availability in soil ranged as follows: N (250.24-350.10 kg ha-1), P (17.4-30.4 kg ha-1), K (400.1-435.7 kg ha-1), Ca (20.00-45.32 cmol (p+) kg-1), Mg (6.30-15 cmol (p+) kg-1), and S (8.5-15.8 mg kg-1). Micronutrient levels were Fe (3.10-5.75 mg kg-1), Mn (5.18-9.44 mg kg-1), Zn (0.20-0.95 mg kg-1), Cu (0.30-1.50 mg kg-1), and B (0.22-0.90 mg kg-1). Leaf nutrient content varied, with macronutrients N (1.44-2.71%), P (0.10-0.36%), K (1.39-1.85%), Ca (1.45-2.70%), Mg (0.30-0.60%), and S (0.18-0.30%), and micronutrients Fe (74.5-130.2 mg kg-1), Mn (35.4-80.2 mg kg-1), Zn (14.1-27 mg kg-1), Cu (6.3-9.7 mg kg-1), and B (20.5-38.5 mg kg-1). The yield of sweet orange orchards ranged from 11.5 to 26.2 t ha-1, with fruit acidity and TSS ranging from 0.32 to 0.45% and 8.2 to 9.5%, respectively.