BackgroundBacterivores, mostly represented by protists and nematodes, are a key component of soil biodiversity involved in soil fertility and plant productivity. In the current context of global change and soil biodiversity erosion, it becomes urgent to suitably recognize and quantify their ecological importance in ecosystem functioning.ScopeUsing meta-analysis tools, we aimed at providing a quantitative synthesis of the ecological importance of soil bacterivores on ecosystem functions. We also intended to produce an overview of the ecological factors that are expected to drive the magnitude of bacterivore effects on ecosystem functions.ConclusionsBacterivores in soil contributed significantly to numerous key ecosystem functions. We propose a new theoretical framework based on ecological stoichiometry stressing the role of C:N:P ratios in soil, microbial and plant biomass as important parameters driving bacterivore-effects on soil N and P availability for plants, immobilization of N and P in the bacterial biomass, and plant responses in nutrition and growth
Soil organisms provide crucial ecosystem services that support human life. However, little is known about their diversity, distribution, and the threats affecting them. Here, we compiled a global dataset of 60 sampled earthworm communities from over 7000 sites in 56 countries to predict patterns in earthworm diversity, abundance, and biomass. We identify the environmental drivers shaping these patterns. Local species richness and abundance typically peaked at higher latitudes, while biomass peaked in the tropics, patterns opposite to those observed in aboveground organisms. Similar to many aboveground taxa, climate variables were more important in shaping earthworm communities than soil properties or habitat 65 cover. These findings highlight that, while the environmental drivers are similar, conservation strategies to conserve aboveground biodiversity might not be appropriate for earthworm diversity, especially in a changing climate.
Nowadays, in a context of climate change, economical uncertainties and social pressure to mitigate agriculture externalities, farmers have to adopt new cropping systems to achieve a sustainable and cost-effective grain production. Conservation agriculture consists of a range of cropping systems based on a combination of three main principles: (1) soil tillage reduction, (2) soil protection by organic residues and (3) diversification in crop rotation. Conservation agriculture has been promoted as a way to reduce production costs, soil erosion and soil fertility degradation under both tropical and temperate conditions. Conservation agriculture-based cropping systems have diffused widely under Brazilian large-scale farms' conditions and more recently in Europe in the context of medium-size mechanized farms. Their diffusion, however, is still limited under small-scale non-mechanized farms' conditions of tropical countries. To assess the advantages and limits of such new cropping systems, this article compares experiences with conservation agriculture from the tropical Cerrado region of Brazil and from temperate conditions of Europe. It focusses on agronomic performances, environmental impacts and economical results. Conservation agriculture systems appear to be interesting options to achieve sustainable and intensive crop production under different agroecological environments because they use efficiently available resources and maintain soil fertility. However, this mostly results from the permanent presence of an organic mulch on the soil surface and the incorporation of cover crops in the rotations. Such modifications require a significant reorganization of the production process at farm level, and when facing technical or socioeconomic constraints, most farmers usually opt for applying only partially the three main principles of conservation agriculture. Investigating more fully the consequences of such partial implementation of conservation agriculture principles on its actual efficiency and assessing the most efficient participatory approaches needed to adapt conservation agriculture principles to local conditions and farming systems are top priorities for future research. (Résumé d'auteur
Priming effect (PE) is defined as a stimulation of the mineralization of soil organic matter (SOM) following a supply of fresh organic matter. This process can have important consequences on the fate of SOM and on the management of residues in agricultural soils, especially in tropical regions where soil fertility is essentially based on the management of organic matter. Earthworms are ecosystem engineers known to affect the dynamics of SOM. Endogeic earthworms ingest large amounts of soil and assimilate a part of organic matter it contains. During gut transit, microorganisms are transported to new substrates and their activity is stimulated by (i) the production of readily assimilable organic matter (mucus) and (ii) the possible presence of fresh organic residues in the ingested soil. The objective of our study was to see (i) whether earthworms impact the PE intensity when a fresh residue is added to a tropical soil and (ii) whether this impact is linked to a stimulation/inhibition of bacterial taxa, and which taxa are affected. A tropical soil from Madagascar was incubated in the laboratory, with a 13 C wheat straw residue, in the presence or absence of a peregrine endogeic tropical earthworm, Pontoscolex corethrurus. Emissions of 12 CO 2 and 13 CO 2 were followed during 16 days. The coupling between DNA-SIP (stable isotope probing) and pyrosequencing showed that stimulation of both the mineralization of wheat residues and the PE can be linked to the stimulation of several groups especially belonging to the Bacteroidetes phylum. The ISME Journal (2012) 6, 213-222; doi:10.1038/ismej.2011; published online 14 July 2011 Subject Category: microbial ecology and functional diversity of natural habitats
No abstract
Avec les remerciements pour Jodie ThénardConventional agriculture strongly alters soil quality due to industrial practices that often have negative effects on soil life. Alternative systems such as conservation agriculture and organic farming could restore better conditions for soil organisms. Improving soil life should in turn improve soil quality and farming sustainability. Here, we have compared for the first time the long-term effects of conservation agriculture, organic farming, and conventional agriculture on major soil organisms such as microbes, nematofauna, and macrofauna. We have also analyzed functional groups. Soils were sampled at the 14-year-old experimental site of La Cage, near Versailles, France. The microbial community was analyzed using molecular biology techniques. Nematofauna and macrofauna were analyzed and classified into functional groups. Our results show that both conservation and organic systems increased the abundance and biomass of all soil organisms, except predaceous nematodes. For example, macrofauna increased from 100 to 2,500 %, nematodes from 100 to 700 %, and microorganisms from 30 to 70 %. Conservation agriculture showed a higher overall improvement than organic farming. Conservation agriculture increased the number of many organisms such as bacteria, fungi, anecic earthworms, and phytophagous and rhizophagous arthropods. Organic farming improved mainly the bacterial pathway of the soil food web and endogeic and anecic earthworms. Overall, our study shows that long-term, no-tillage, and cover crops are better for soil biota than periodic legume green manures, pesticides, and mineral fertilizers
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
334 Leonard St
Brooklyn, NY 11211
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.