Integrated Effects of Potassium Humate and Planting Density on Growth, Physiological Traits and Yield of <i>Vicia faba</i> L. Grown in Newly Reclaimed Soil

Several agronomic factors, including planting density, affect plant growth and final yield. New soil suffers from severe fertility shortage and crop productivity. Potassium humate (KH) application improves soil fertility and plant performance under new soil conditions. Therefore, this investigation was performed in two seasons of 2018/2019 and 2019/2020 to study the impact of KH application at the rate of 50 kg hectare⁻¹ (ha⁻¹) on growth, yield, physio-biochemical attributes, plant water status and nutrients in faba bean plants grown in newly reclaimed soil under three planting densities, i.e., D₁ = 222.222 plants ha⁻¹ (15 × 60 cm), D₂ = 166.666 plants ha⁻¹ (20 × 60 cm) and D₃ = 133.333 plants ha⁻¹ (25 × 60 cm). The results showed that KH application enhanced tissue water status by increasing the membrane stability index (MSI%) and relative water content (RWC%), while electric leakage (EL%) was reduced, alongside increased growth attributes physio-biochemical properties and nutrients. These results were positively reflected by the improved yield and its components (i.e., number of pods plant⁻¹, 100-seed weight, seed yield plant⁻¹ and seed yield ha⁻¹) in favor of the medium planting density (166.666 plants ha⁻¹). The results of the current study showed that the application of KH with the medium planting density (20 × 60 cm) was the best treatment combination to enhance the performance and productivity (2.97 ton ha⁻¹<b>)</b> of faba bean plants grown under newly reclaimed soil conditions.