Thermochemical digestate fertilizer from solid waste: Characterization, labile carbon dynamics, dehydrogenase activity, water holding capacity and biomass allocation in banana

Abstract

Thermochemical digestion is a rapid technology of biowaste management resulting in the instant production of organic fertilizer. Characterization and assessment of its suitability as an organic fertilizer is essential for recommendation for crop application. Biowaste and the thermochemical digestate were subjected to physicochemical and biochemical characterization and the compost maturity parameters assessed. The product integrated with inorganic fertilizers was tested in an Ultisol grown with banana in comparison with farmyard manure based fertilizers. Temporal variation in soil reaction, water holding capacity, carbon dynamics, dehydrogenase activity and plant biomass were determined. The thermochemical digestate fertilizer had a bulk density (0.76 Mg m-3), pH (neutral), C:N ratio (16.26), CEC (85.70 cmol(+) kg-1), CEC/ TOC ratio (3.99), Fertilizing index (4.7) and a Clean index (5.0). Field evaluation revealed enhanced water holding capacity (38.75-83.17%). Total carbon increased with consistently high labile (R 2 = 0.9551) and non labile carbon fractions and the lowest average lability index (0.78). Dehydrogenase activity at harvest enhanced by 72.81%. An even biomass allocation resulted in 38.84% more biomass production in the fruit over farmyard manure based treatments. In addition to ensuring the safety of the environmental ecosystem, the thermochemical digestate conformed to be a quality resource favoring microbial proliferation and carbon sequestration, thereby restraining carbon dioxide emission. The thermochemical digestate fertilizer based nutrition serves the key deliverables of natural resource management, ecofriendly rapid disposal of biowaste and quality organic fertilizer for banana in Ultisols.