Bioassay for bioremediation of degraded agricultural soil using bokashi compost with mountain microorganisms and bell pepper (Capsicum annum) indicator plants

Abstract

The research aimed to regenerate degraded soils by obtaining samples in the commune of Los Bajos del Pechiche, canton Montecristo, Ecuador. Germination trays and samples of partially degraded and degraded soils as well as fertile soil were used as control for results comparison. Characterization of bokashi with mountain microorganisms was carried out in laboratories using physical, chemical, and microbiological analyses. In a bioassay, bell pepper seedlings were evaluated in treatments of degraded soil mixtures with different combinations of bokashi with mountain microorganisms through response variables: germination at 10 days, number of leaflets in seedlings at 15-30 days, plant height at 30 days and root diameter at 30 days. The doses of bokashi with mountain microorganisms were mixed with degraded soil in the following proportions 25%, 50%, and 75%, respectively. The best treatments were established as 75% degraded and partially degraded soil plus 25% bokashi with mountain microorganisms since the highest values were obtained in the different variables. The laboratory analyses presented bokashi organic fertilizer with mountain microorganisms as an excellent alternative for the regeneration of degraded agricultural soils. The results when compared with the analysis of degraded soil and the levels of FAO concerning the soils using a universal scale demonstrated its efficient alternative for bioremediation. Regarding the economic dimension, it has very high values unfeasible for producers or farmers. Then, the Ecuadorian State should establish promotion policies, including subsidies to make the regeneration of degraded soils a reality and not a utopia.