Chambres dAgriculture de Bretagne

Vannes, France

Chambres dAgriculture de Bretagne

Vannes, France
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Bottinelli N.,IRD Montpellier | Angers D.A.,Agriculture and Agri Food Canada | Hallaire V.,Agrocampus Ouest | Michot D.,Agrocampus Ouest | And 4 more authors.
Soil and Tillage Research | Year: 2017

Reduced tillage and organic fertilizer application usually result in an increase in soil aggregate stability (AS). However, the magnitude of the effects can vary with soil properties and season. The aim of this study was to investigate AS dynamics over three seasons in a soil under various tillage and fertilization practices. The study was performed under three tillage practices (moldboard plowing (MP), surface tillage (ST) and no-tillage (NT)) and two types of fertilizer (poultry manure and mineral) seven and eight years after their establishment in Northwest France. AS was measured in three different seasons: spring, summer and winter. Soil properties that potentially influence AS such as organic carbon (OC), hot-water extractable carbohydrates (HWEC), water content (WC) and water repellency (WR) were also studied. On average, for all sampling dates, AS was 34% higher under NT than MP. Conversely, the effect of ST on AS varied with sampling date with values close to NT in mid-spring and summer, and values close to MP in early spring and winter. Poultry manure increased AS by an average of 12% regardless of sampling date or tillage practice. Variations in AS due to management practices were related to OC (r = 0.92) and HWEC (r = 0.88). Differences in AS between sampling dates were slightly greater than the effects of management practices. On average across management practices, AS increased by 47% from early spring to summer and decreased by 59% in winter. These variations were related to soil WC (r = −0.67) and WR (r = 0.72) at time of sampling. We suggest that seasonal variations in AS were at least partly due to variations in WC which acted physically by modifying the water entry rate into the aggregates and slaking effects. In contrast, the long-term AS dynamics were related to the organic matter dynamics, which are controlled by management practices. Because of the predominant effect of climate on AS, we suggest measuring AS in winter and summer to better estimate the effects of management practices on soil erodibility in this region. © 2017 Elsevier B.V.

Morand P.,CNRS Ecosystems, Biodiversity, and Evolution Laboratory | Robin P.,French National Institute for Agricultural Research | Escande A.,Montpellier University | Picot B.,Montpellier University | And 11 more authors.
AIP Conference Proceedings | Year: 2010

From preliminary researches on a pilot scale, a complete demonstration plant was built to treat the effluents of a 30 pregnant sow's piggery. It includes a screen, a vermifilter, a macrophyte lagooning, and a complementary water storage pond; the recycled water is used for flushing, and rainfall is collected to compensate for evapotranspiration. After functioning in 2008 and 2009, it was showed that, during the warm season, the whole plant produced an effluent suitable for flushing, where the concentration decrease was over 70% for the phosphorus and potassium, 95% for the COD and nitrogen, 99.8% for endocrine disruptors (estrogenic activity), and 99.99% for pathogenic micro-organisms. During the cold season, the dilution by the rain water and the treatment effect of the constructed wetlands lead to similar results. Nevertheless, for this season, suitable floating macrophytes that will cover the lagoons remain to be settled. © 2010 American Institute of Physics.

Alletto L.,Purpan Engineering School | Coquet Y.,French National Institute for Agricultural Research | Benoit P.,French National Institute for Agricultural Research | Heddadj D.,Chambres dAgriculture de Bretagne | Barriuso E.,French National Institute for Agricultural Research
Agronomy for Sustainable Development | Year: 2010

Reducing tillage intensity through the implementation of conservation practices is a way to reach a more sustainable agriculture. Reducing tillage is indeed an efficient way to control soil erosion and to decrease production costs. Nonetheless, the environmental impact of reduced tillage is not well known because conservation techniques may induce strong changes in soil physicochemical properties and biological activity. Knowledge on the fate of applied pesticides under conservation practices is particularly important from this point of view. We review here the advances in the understanding, quantification and prediction of the effects of tillage on pesticide fate in soils. We found the following major points: (1) for most dissipation processes such as retention, degradation and transfer, results of pesticide behaviour studies in soils are highly variable and sometimes contradictory. This variability is partially explained by the multiplicity of processes and contributive factors, by the variety of their interactions, and by their complex temporal and spatial dynamics. In addition, the lack of a thorough description of tillage systems and sampling strategy in most reports hampers any comprehensive interpretation of this variability. (2) Implementation of conservation tillage induces an increase in organic matter content at the soil surface and its gradual decrease with depth. This, in turn, leads to an increase in pesticide retention in the topsoil layer. (3) Increasing retention of pesticides in the topsoil layer under conservation tillage decreases the availability of the pesticides for biological degradation. This competition between retention and degradation leads to a higher persistence of pesticides in soils, though this persistence can be partially compensated for by a more intensive microbial activity under conservation tillage. (4) Despite strong changes in soil physical properties under conservation tillage, pesticide transfer is more influenced by initial soil conditions and climatic conditions than by tillage. Conservation tillage systems such as no-tillage improve macropore connectivity, which in turn increases pesticide leaching. We conclude that more knowledge is needed to fully understand the temporal and spatial dynamics of pesticide in soil, especially preferential flows, in order to improve the assessment of pesticide risks, and their relation to tillage management. © 2009 INRA, EDP Sciences.

Boizard H.,French National Institute for Agricultural Research | Peigne J.,ISARA Lyon | Sasal M.C.,Instituto Nacional de Tecnologia Agropecuaria | de Fatima Guimaraes M.,State University Londrina | And 11 more authors.
Soil and Tillage Research | Year: 2016

In France, agronomists have studied the effects of cropping systems on soil structure using a field method that is based on a visual description of the soil structure. This "profil cultural" method was designed as a field diagnostic tool to identify the effects of tillage and compaction on soil structure dynamics. It is of great benefit to agronomists seeking to improve crop management and preserve soil structure and fertility.However, the "profil cultural" method was developed and has mainly been used in conventional tillage systems with regular ploughing. As there has been an increase in the use of various forms of reduced, minimum and no-tillage systems in many parts of the world, it is necessary to re-evaluate this method's ability to describe and interpret soil structure dynamics in no-till or reduced tillage. In these situations, changes in soil structure over time are mainly driven by compaction and by regeneration through natural agents (climatic conditions, root growth and macrofauna), therefore it is important to evaluate the effects of these natural processes on soil structure dynamics.These concerns have led to adaptations and amendments to the initial method based on field observations and experimental work in different cropping systems, soil types and climatic conditions. The description of crack types has been improved and a criterion of biological activity based on the visual examination of clods has been introduced.To test this modified method, a comparison with the initial method was undertaken and its ability to make diagnoses tested in five experiments in France, Brazil and Argentina. The adapted method allowed an improved assessment of the impact of cropping systems on soil functioning when natural processes were integrated into the description. © 2016 Elsevier B.V.

Morand P.,CNRS Ecosystems, Biodiversity, and Evolution Laboratory | Robin P.,French National Institute for Agricultural Research | Pourcher A.-M.,IRSTEA | Oudart D.,Chambres dAgriculture de Bretagne | And 5 more authors.
Water Science and Technology | Year: 2011

Since 2001 the swine experimental station of Guernévez has studied biological treatment plants for nutrient recovery and water recycling, suited to the fresh liquid manure coming out of flushing systems. An integrated system with continuous recycling was set up in 2007, associated with a piggery of 30 pregnant sows. It includes a screen, a vermifilter, and macrophyte ponds alternating with constructed wetlands. The screen and the vermifilter had a lower removal efficiency than in previous studies on finishing pigs. A settling tank was then added between the vermifilter and the first lagoon to collect the worm casts. A second vermifilter was added to recover this particulate organic matter. A storage lagoon was added to compensate for evaporative losses and complete pollution abatement, with goldfish as a bioindicator of water quality. The removal efficiency of the whole system was over 90% for COD and nitrogen, over 70% for phosphorus and potassium, and more than 4 logarithmic units for pathogens (E. coli, enterococci, C perfringens). Plant production was about 20 T DM ha-1 y-1. Floating macrophytes (Azolla caroliniana, Eichhornia crassipes, Hydrocotyle vulgaris) were more concentrated in nutrients than helophytes (Phragmites australis, Glyceria aquatica,y). Azolla caroliniana was successfully added to feed finishing pigs. & IWA Publishing 2011.

Morand P.,CNRS Ecosystems, Biodiversity, and Evolution Laboratory | Robin P.,French National Institute for Agricultural Research | Escande A.,Montpellier University | Picot B.,Montpellier University | And 11 more authors.
Procedia Environmental Sciences | Year: 2011

A wastewater treatment system including a screen, a vermifilter, macrophytes ponds, and constructed wetlands has been built after a pig housing on slatted-floor. The aims were, all at once, to recycle water for excretion washing and to produce, from the nutrients contained in the effluent, organic matter and plants that can be either sold or reused on the farm to reduce inputs. Analyses, made on the effluent at different steps of the treatment plant, show that the concentrations of the nitrogen, microorganisms and endocrine disruptors are drastically reduced, while the phosphorus and potassium removal go through the byproducts harvesting. © 2011 Published by Elsevier Ltd.

Luth,CNRS Ecosystems, Biodiversity, and Evolution Laboratory | Luth,Agrocampus Ouest | Robin P.,Agrocampus Ouest | Germain P.,Agrocampus Ouest | And 4 more authors.
Bioresource Technology | Year: 2011

Treatment of liquid manure can result in the production of ammonia, nitrous oxide and methane. Earthworms mix and transform nitrogen and carbon without consuming additional energy. The objective of this paper is to analyse whether earthworms modify the emissions of NH3, N2O, CH4 and CO2 during vermifiltration of pig slurry. The experiment used mesocosms of around 50. L, made from a vermifilter treating the diluted manure of a swine house. Three levels of slurry were added to the mesocosms, with or without earthworms, during one month, in triplicate. Earthworm abundance and gas emissions were measured three and five times, respectively. There was a decrease in emissions of ammonia and nitrous oxide and a sink of methane in treatments with earthworms. We suggest that earthworm abundance can be used as a bioindicator of low energy input, and low greenhouse gas and ammonia output in systems using fresh slurry with water recycling. © 2010 Elsevier Ltd.

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