Development of artificial fertility gradient using fodder sorghum and its effect on soil nutrients, nutrient uptake and fodder yield

Fertilizers play a vital role in enhancing crop production, and optimizing their application is essential for achieving higher yields. This study examines the effects of an artificial fertility gradient on soil fertility, nutrient uptake, and fodder yield of sorghum (Sorghum bicolor) using the Inductive cum Targeted Yield Model. A field experiment was conducted at the N.M. College of Agriculture, Navsari Agricultural University, Gujarat, during the kharif 2022. The experimental site was divided into three strips with graded doses of nitrogen (N), phosphorus (P₂O₅), and potassium (K₂O): Strip I (N₀P₀K₀: 0-0-0 kg ha⁻¹), Strip II (N₁P₁K₁: 80-40-40 kg ha⁻¹), and Strip III (N₂P₂K₂: 160-80-80 kg ha⁻¹). Results indicated that fertilizer application significantly influenced soil fertility, nutrient uptake, and fodder yield. Post-harvest soil nutrient levels showed a considerable increase in Strip III compared to Strips I and II, confirming the creation of an artificial fertility gradient. Sorghum fodder yield was significantly higher in Strip III (29.87 t ha⁻¹), representing a 480% and 90.3% increase over Strips I and II, respectively. Nutrient uptake followed a similar trend, with maximum N, P, and K uptake observed in Strip III (75.55, 69.88, and 131.58 kg ha⁻¹, respectively). The findings demonstrate that higher fertilizer application enhances nutrient availability, uptake, and crop productivity. This study provides empirical evidence supporting targeted fertilization strategies for optimizing fodder sorghum production and improving soil fertility management.