Influence of Microbial Inoculation of Igneous Rock Phosphate-Amended Cow and Pig Manures on Vermidegradation and Nutrient Release

Abstract

Vermicomposting using Eisenia fetida has been shown to improve phosphorus mineralization from rock phosphate (RP). There is, however, a lack of information on the potential of integrating microbial inoculants like phosphate-solubilizing bacteria (PSB) during vermicomposting as a way of improving vermidegradation, and the release of nutrients from igneous RP-amended composts. This study evaluated the potential of using Eisenia fetida and Pseudomonas fluorescence in enhancing the vermidegradation, and nutrient release in igneous RP- amended cow and pig manure-based vermicomposts at a C/N ratio of 30. Compost maturity, nutrient and phytotoxicity parameters were measured to determine vermicompost quality. Final vermicompost results showed that the pig manure treatments achieved greater maturity as indicated by lower C/N of 10.3, high humification index (HI) of 7.6%, and humification ratio (HR) of 12.89% in the treatment with E. fetida and P. fluorescence. The inclusion of E. fetida alone in cow manure treatment resulted in the highest Olsen P of 2600 mg/kg, followed by the pig manure treatment with E. fetida only (2246.15 mg/kg). In conclusion, both E. fetida and P. fluorescence are necessary in the vermicomposting of RP-enriched pig and cow manure for efficient vermi-degradation and nutrient release.

Vermicompost Amended With Rock Phosphate as a Climate Smart Technology for Production of Organic Swiss Chard (Beta vulgaris subsp. vulgaris)

“…With the presence of humic acids in the organic amendments used in the present study as recorded in the study of Ajibade et al (2020) and the goethite present in the Oxisol soil (Manyevere, 2014) used in the present study, the highest P tissue content observed after the application of 50 mg P kg −1 can be explained by the highest rate of organic amendment used. For example, Yan et al (2016) prepared goethite-humic acid complexes to investigate their P adsorption characteristics and found that the presence of organic compounds reduces goethite-humic acid complexes' P adsorption capacity.…”

“…This shows that heavy metal concentration through vermicompost differs according to the feed used during vermicomposting. Moreover, the overall low plant uptake of heavy metals in the present study in connection to increased humic substances in the organic P amendments used in the present study (Ajibade et al, 2020) can be explained by the binding ability (e.g., ion exchange, complexation, and physical adsorption) of humic substances for heavy metals and the immobilization of heavy metals through redox reaction (Tang et al, 2014;Yao et al, 2019). These reduced metals show that adding cow and pig manure RP vermicompost to Oxisol soil did not directly affect the Swiss chard plant.…”

“…The RP-enriched cow and pig manure vermicompost with phosphorus-solubilizing bacteria (PSB) (P. fluorescens) prepared as described by Ajibade et al (2020) was used for the seedling stage. The growth media used for the seedling study consisted of commercial pine bark compost that was collected from Rance Timbers, Stutterheim, Eastern Cape, South Africa.…”

“…There is growing evidence that some microorganisms can enhance the solubilization of RP. More recently, a study by Ajibade et al (2020) demonstrated the capacity of Pseudomonas fluorescens to solubilize a low-grade RP during the cow and pig manure RP-enriched vermicomposting process. The highest Olsen P content of 3,342.64 and 3,051.20 mg kg −1 after week 6 of vermicomposting was observed in the cow and pig manure RP-enriched vermicompost treatments inoculated with P. fluorescens.…”

Unveiling the Efficiency of Psychrophillic Aporrectodea caliginosa in Deciphering the Nutrients from Dalweed and Cow Manure with Bio-Optimization of Coprolites

“…The increase in both HR and HI in the vermicastings is due to the combined action of earthworm-microbes and is also based on the initial chemical composition of different mixture substrates. A recent study also confirmed the positive influence of vemicomposting on humification of cow and pig manure blended with paper wastes [64,65], and other scientific reports projected the highest humification degree in recycling of municipal solid waste blended with cow dung [66]. The high HI during the vermicomposting could also have contributed to the improvement in mineralization and dissolution of organic matter which reflected an increased percentage of humic acid (Pha) in the coprolites.…”