Improving Soil Agriculture Properties by the Implication of Compost, Compost Tea, and Soil Microorganisms

Abstract

Soil fertility and productivity challenges are growing with every passing day in view of changing global climate and increasing human population. One of the most viable and valuable options is the application of sustainable biotechnological practices. Present study investigated the effects of compost, compost tea, and selected bacterial strains on soil properties and plant growth parameters in autoclaved and unautoclaved soils. Compost and compost tea were prepared using simple carbon source (molasses) following standard composting principles. Selected Bacillus strains were isolated from Solanum lycopersicum (tomato plant) rhizosphere soil and screened for antifungal activity against Fusarium oxysporum, Aspergillus flavus, and Aspergillus niger. The results showed that four Bacillus isolates S1, S2, S4, and S10 exhibited significant antagonistic activity and reduced Fusarium oxysporum growth by (41.9 ± 1%), (39.4 ± 1%), (42.1 ± 3%), and (46.6 ± 1%) respectively. Bacillus strain S4 caused an inhibition of Fusarium oxysporum (46.6% ± 1), Aspergillus flavus (62.40 ± 1%) and Aspergillus niger (66.6 ± 0%) in vitro experiments. In order to investigate plant growth promoting traits, bacteria were assessed for their abilities to solubilize phosphate and zinc along with nitrogen fixation, protease, catalase, oxidase production abilities. Bacillus strain S2 and S10 showed positive response toward phosphate and zinc solubilization. Soil organic matter in post-harvested soil was found to be 2.86 times higher as compared to pre-harvested one, while the elemental ratios were N (1.35 ± 0.19%), P (0.51 ± 0.07%) and K (0.38 ± 0%), respectively, after treatment with compost (CM) + compost tea (CT) + Bacterial consortia (BC). In both autoclaved and unautoclaved soils, the application of compost, compost tea, and bacterial consortia significantly influenced plant growth characteristics. In autoclaved soil, the addition of CM+CT+BC led to a remarkable plant height (77.66 ± 4.04 cm), fresh and dry weight (19.55 ± 3.05 g and 3.32 ± 0.97 g), primary root length (7.20 ± 1.80 cm) and chlorophyll content (43.63 ± 3.35) were achieved. In conclusion, this study highlights the potential benefits of compost, compost tea, and specific bacterial strains in improving soil quality and promoting plant growth leading to sustainable food production.