Composts and Water Extracts of Lignocellulosic Composts in the Aspect of Fertilization, Humus-Forming, Sanitary, Phytosanitary and Phytotoxicity Value Assessment

Abstract

Purpose Lignocellulosic biomass waste is produced in large quantities and only a small part is used for utility purposes. The aim of the work was to assess the fertilization value of the solid fraction and water extract of lignocellulosic composts. Methods Compost I contained 42.86% pine bark, 34.28% grass, 20.0% sawdust and 2.86% chicken feathers; compost II contained 25.54% pine bark, 10.63% wheat straw, 51.07% sawdust and 12.76% chicken feathers. Seldom described physical properties and phytosanitary and sanitary status of composts as well as macro-and micronutrients and heavy metals concentrations were determined in the solid fraction and water extracts of composts and their impact on the germination of Lepidium sativum L. using PC analysis. Results Composts were characterized by good physical properties and a light product, safe phytosanitary status, which was related to the prevalence of potentially antagonistic fungi, especially in compost II. The frequency of Aspergillus fumigatus, considered an opportunistic human pathogen, decreased during the composting. Heavy metal concentrations did not exceed permissible values for improvers and cultivation media in the solid and aqueous compost fractions. The tested composts were sanitary safe. Both composts were non-toxic to plants, because the germination index in compost I was PCA analysis demonstrated that the majority of micro-and macronutrients and heavy metals had a significantly negative effect on root elongation and germination of the test plant (cress) seeds, especially in compost I. Conclusions Lignocellulosic waste after composting is a valuable and safe organic fertilizer.

Evaluation of Wood Ash as Additive for Cow Manure Composting

“…To evaluate the compost maturity and their phytotoxicity, a germination assay was conducted with corn seeds and the Germination Index (GI) was determined according to [5]- [17]. The germination test was carried out (in triplicate) on filter paper in petri dishes.…”

“…A maturation phase starts from the 49th day (temperature equal to 25 °C). During this phase, the temperatures of the treatments were confused with the ambient temperature [5] which showed that there was no longer any significant activity of the microorganisms. During this phase, precursors of humus and slow degradation of resistant compounds slowly appear [3], resulting in a dark brown to black coloration of the compost and making it thinner and more homogeneous [25]- [26].…”

“…[1]- [3]. Composting is a microbiological biodegradation process during which bio-waste is transformed into carbon dioxide, inorganic salts and humid substances, and heat is generated resulting from the metabolic activity of microorganisms [4]- [5]- [6]. Composting raw materials consist mainly of plant residues and relatively few remains of animals or minerals [7].…”

“…Composting raw materials consist mainly of plant residues and relatively few remains of animals or minerals [7]. The resulting composts contain organic compounds precursors of humus and fertilizers, by their content of nutrients [8]- [9]- [11]. Compost thus makes it possible to fill the deficit of over-exploited soils and to improve their longterm fertility.…”

“…This results in a loss of stable organic matter in soils and an increased susceptibility of plants to diseases, due to the microbiological imbalance of soils [6]. Various countries are facing a significant increase in waste [4], however, much of this waste is organic in nature, and recycling through composting would make up for the moisture deficit of overexploited soils and reactivate a balanced microbiological life [5]- [6]- [7]. Urban municipalities in general and large metropolises in Africa are struggling to evacuate and treat their urban waste.…”