Integrated Effect of Rhizobium Inoculation, Phosphorus, and Zinc on Soil Physico-Chemical Properties under Chickpea (Cicer arietinum L.) Cultivation

Abstract

A field experiment was carried out at the Student’s Instructional Farm, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, during the rabi seasons of 2023-24 and 2024-25 to investigate the effects of rhizobium, zinc, and phosphorus inoculation on soil physico-chemical properties under chickpea (Cicer arietinum L.) variety KPG-59 (Uday). Eighteen Treatments combinations were used in the factorial randomized block design (FRBD), which included two rhizobium inoculation levels (with and without), three phosphorus levels (0, 30, and 60 kg ha⁻¹), and three zinc levels (0, 2.5, and 5.0 kg ha⁻¹). The soil's pH was 7.77 and 7.69 before to planting, and electrical conductivity was 0.35 and 0.34 d Sm⁻¹, the particle density was 2.69 and 2.68 Mg m⁻³, and the bulk density was 1.41 and 1.40 Mg m⁻³ in 2023 and 2024. In addition to zinc and rhizobium inoculation, the results showed that raising phosphorus levels from P₀ to P₆₀ improved soil physico-chemical characteristics. The control (P₀) had the lowest mean values of soil pH (7.84), EC (0.348 d Sm⁻¹), bulk density (1.40 Mg m⁻³), and particle density (2.70 Mg m⁻³), whereas treatment T17 (60 kg P + 2.5 kg Zn + Rhizobium) and T18 (60 kg P + 5.0 kg Zn + Rhizobium) had the maximum values of soil pH (7.79), EC (0.340 d Sm⁻¹), bulk density (1.39 Mg m⁻³), and particle density (2.69 Mg m⁻³).  The best results were obtained when phosphorus, zinc, and rhizobium were applied together to improve soil quality and chickpea cultivation.