Chemical and Microbial Characterization of Fermented Forest Litters Used as Biofertilizers

Abstract

The excessive use of chemicals in intensive agriculture has had a negative impact on soil diversity and fertility. A strategy for developing sustainable agriculture could rely on the use of microbial-based fertilizers, known as biofertilizers. An alternative to marketed products could be offered to small farmers if they could produce their own biofertilizers using forest litters, which harbor one of the highest microbial diversities. The aim of this study is to characterize microbial communities of Fermented Forest Litters (FFL), assuming that the fermentation process will change both their abundance and diversity. We investigated two types of differing in the chemical composition of the initial litters used and the climatic context of the forest where they are originated from. The abundance and diversity of bacterial and fungal communities were assessed using quantitative PCR and molecular genotyping techniques. The litter chemical compositions were compared before and after fermentation using Infrared spectrometry. Results obtained showed that fermentation increased the abundance of bacteria but decreased that of fungi. Low pH and change in organic matter composition observed after fermentation also significantly reduced the α-diversity of both bacterial and fungal communities. The higher proportion of aliphatic molecules and lower C/N of the FFLs compared to initial litters indicate that FFLs should be rapidly decomposed once added into the soil. This preliminary study suggests that the agronomic interest of FFLs used as biofertilizers is probably more related to the contribution of nutrients easily assimilated by plants than to the diversity of microorganisms that compose it. Further studies must be conducted with sequencing techniques to identify precisely the microbial species likely to be beneficial to plant growth.

Challenges and Opportunities in Biofertilizer Commercialization

“…Moreover, the efficacy of biofertilizers is not universal but varies depending on the cultivar of the crop. For instance, strawberries' response to bacterial inoculation is highly cultivar-dependent [53]. This calls for targeted breeding programs focusing on yield, fruit quality, and adaptability to various growing systems, enhancing consumer acceptance.…”

Pour une gestion durable des sols en Afrique subsaharienne

“…Il s'agit en premier lieu de faire évoluer les programmes de recherche, souvent focalisés sur un seul modèle technique considéré comme « le bon », sans prendre en compte l'ensemble des ressources des territoires ou des contraintes soulevées par les agriculteurs. De nombreux domaines de recherche spécifiques à la fertilité des sols doivent être renforcés, comme la microbiologie des sols, la santé des plantes, la fertilité physique du sol, la mécanisation agricole et la gestion du travail... Les travaux sur le microbiote des sols et leur valorisation par les agronomes ouvrent de nouvelles perspectives comme celles du renforcement des défenses des plantes et une meilleure valorisation des nutriments apportés ou contenus dans le sol : sélection de souches microbiennes locales et utiles aux cultures, fabrication et apport de litière forestière fermentée (LIFOFER), de compost bokashi... (Marois et al, 2023 ;Noumsi-Foamouhoue et al, 2023). Il s'agit également pour la recherche de mieux considérer les dimensions techniques (fertilité des sols associée aux effets sur la santé humaine, avec par exemple la diversification de la diète via des légumineuses) et environnementales (résilience face au changement climatique) des pratiques, et les potentiels impacts sur les dimensions économiques et sociales.…”