Abstract

A pot experiment was conducted to evaluate the effects of organic amendments and biofertilizers on the soil properties and growth of Centrosema pubescens seedlings. The study involved six treatment combinations consisting of two inoculation levels (with and without biofertilizers) and three rates of organic amendments (0, 15, and 30 g/kg soil), arranged in a randomized complete block design with three replications. Organic amendments were prepared as a mixture of chicken manure, vermicast, and rice hull biochar in a 2:1:1 ratio (v/v), while the biofertilizer consisted of Trichoderma harzianum, Bacillus subtilis, and arbuscular mycorrhizal fungi. Soil analysis after harvest showed that organic amendments improved organic matter, total nitrogen, available phosphorus, exchangeable potassium, as well as available copper and zinc, but reduced soil pH, iron, and manganese. The 30 g/kg application rate consistently produced the most notable improvements. Biofertilizer application significantly enhanced plant performance, resulting in taller plants, more leaves, greater leaf area, thicker stem diameter, higher shoot and root biomass, longer roots, and increased root nodulation. Meanwhile, the combined application of organic amendments and biofertilizers resulted in higher leaf number, larger leaf area, and heavier shoot weights. These results highlight the potential of using organic amendments and biofertilizers to improve soil fertility and promote plant growth, supporting the rehabilitation of mined-out areas.

Key words: Organic amendments, Soil fertility, Nutrient availability, Biofertilizers, Mined-out soil rehabilitation.