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Decadal manure substitution reshapes microbial communities to drive plant and microbial carbon accumulation in soil carbon fractions
No full textInternational audienceThe transformation of organic residues into particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) governs soil organic carbon (SOC) storage and stability. However, how long-term manure use steers plant-and microbe-derived SOC fractions in paddy soils remains unclear. The SOC in paddy soil was evaluated by measuring amino sugars, lignin and enzyme activities from a 12-yr field trial (rice-wheat rotation) with no fertilizer, 100% mineral N fertilizer, and pig manure (50% and 100% replacement of N fertilizer). Compared to mineral N, the 100% pig manure treatment increased SOC by 26%, mainly through enhanced lignin input and microbial necromass accumulation, leading to significantly higher POC and MAOC levels. Manure application, compared to mineral N, promoted rice growth, which increased total organic C input and nutrient availability, thereby selectively favoring r-strategist bacteria, as reflected by a lower vanillyl acid-to-aldehyde ratio, a higher ratio of cellulose-to lignin-degrading enzyme activity, and greater lignin and bacterial necromass production. In contrast, the combined NPK and pig manure treatment increased the proportion of MAOC in total SOC by 7% compared to the 100% manure treatment, yet this came with enhanced lignin degradation, a lower bacterial phospholipid fatty acid (PLFA)/fungal PLFA ratio, and greater abundance of K-strategist fungi, resulting in less POC accumulation. These findings demonstrate that substituting mineral N with pig manure reshapes microbial community, enhancing the microbial transformation of plant-and microbe-derived residue into stable and labile SOC pools, and more effectively promotes SOC sequestration and persistence than mineral fertilization alone in paddy systems
Induced lactation in dairy goat
No full textSession 22 - Théâtre 3International audienceIn a context where kid meat is undervalued, French dairy goat farmers face significant economic, logistical, and ethical challenges. An innovative solution, induced lactation (IL), allows goats to produce milk without gestation,following a dry period. This study identifies the success factors of IL for the first time. An experiment was conducted in South-Eastern France with 162 dairy goats selected from 10 farms. The goats were divided into 2 balanced groups (n=81) based on breed (Alpine, Saanen), parity (primiparous, multiparous), and productivity(low, high): a gestating group (G) and a non-gestating group (NG). NG goats were excluded from reproduction and kept in the same flock as G goats. All goats were dried off in late autumn. After kidding of G goats, farmers manually stimulated the teats of NG goats following a standard protocol for 3 weeks. No hormone treatment was applied. Serum prolactin level, udder thermal and standard images, udder hairiness, udder consistency, and body condition score (BCS) were recorded at five time points: 30 d and 10 d before kidding, 1 d before stimulation,and after 10 d and 21 d of stimulation. The number of NG goats that induced lactation and their milk yield during the 3-week stimulation were recorded. The effect of farm-level and animal-level parameters on the success of IL was tested through logistic regression. The effect of IL on udder parameters and prolactin levels was assessed using mixed ANOVA for repeated measures. After 3 weeks of stimulation, 51% of NG goats began to induce lactation. Breed, parity, productivity, daytime, and prolactin levels had no significant effect (P>0.05) on IL success. On the contrary, NG goats with BCS≥3 at the end of the dry period had a higher chance of induction (odds ratio=4.7, P=0.003). A similar result was observed in goats with outdoor access during the stimulation period (odds ratio=3.3, P=0.023). NG goats that induced lactation had higher teat temperature (P<0.001) and udderwidth (P=0.013) during the dry period. These parameters could be used to identify goats with a higher chance of inducing lactation. The physiological determinants of IL remain to be studied, probably later in lactation when milk production is better induced
Radiation screens and their impact on air temperature measurement: a review
No full textInternational audienceOutdoor air temperature measurements are essential to be applied to agriculture, meteorology, hydrology, and urban planning. Precise measurements are particularly needed in the lower troposphere where the existence of large temperature gradients is prevalent. Urban temperature observation has been an area of research concern in recent years, particularly to study the urban heat island effect, local overheat, and heat reduction measures. Temperature readings most often employ sensors housed in protective shields. Low thermal inertia and fastresponding thermocouples and platinum probes, though less accurate, are two sensor types that are common. Shielding is used to minimize error by protecting sensors from precipitation and direct sunlight and allowing ventilation. Poor shielding can generate large temperature differences, over +4°C. Different shielding designs, such as Stevenson screens, Gill shields, and aspirated shelters, are investigated. Shielding efficiency depends upon their optical property, ventilation, and design. Correction methods like empirical corrections, numerical models including CFD, and neural network are also being considered to maximize data accuracy over urban areas. This paper offers an overview of studies that investigate radiation shields used for the measurement of external air temperatures and compare their performance in terms of various attributes. The methodology for selecting studies is presented first, encompassing field measurements, laboratory experiments, and numerical models. An inter-comparison of literature is then conducted, distinguishing commercially manufactured and home-made shields, ventilated and non-ventilated designs, and other significant features such as shape, size, optical properties, and materials. Errors in measurements, their reasons, and the procedures for correcting them are treated with special care
Distinct standing time response patterns to seasonal heat stress in dairy cows
No full textInternational audienceThresholds are needed to detect and identify heat stress. The response to heat stress may not differ between animals but the dynamics of the response may vary from one animal to another. In the present study, we hypothetised that, when cows are reared indoors, the standing position can be considered as an indicator of heat stress situation. From June 16th to September 15th 2024, data were collected on 158 Holstein dairy cows (parity 1 to 5), in 2 commercial farms located in a temperate climate in western France. In these farms, milking robots were used and cows were housed indoors all year long. Behavioural data (standing, time in holding areas, drinking and eating time, and walking distance) were continuoulsy recorded using the AIherd® device. Temperature, humidity, wind speed and wet bulb globe temperature were also recorded. Information was aggregated on a 4-hours basis, and behavioral data were averaged per slot. Cows were classified according to their behavioural responses using hierarchical ascending classification. Four distinct standing time response patterns were determined, with 3 common clusters: C1 (37%) shows a linear increase, C2 (21%) remains stable until reaching a peak before decreasing, and C3 (19%) increases until a peak and then stabilizes. Although Farm 2 has fan systems, dairy cows in this farm consistently showed higher standing activity (p < 0.05), despite no greater environmental stress, as Farm 1 had a higher temperature by about 0.345°C. This may be due to the barn’s larger area, layout, and the need to stand in alleys to benefit from fans. Our results indicated that standing activity is increasing while intensity of heat stress is increasing, suggesting that it could be an indirect indicator (proxy) to determine intensity of such a stress on individual basis. Including other indicators based on health status, mobility score, access to milking robot, still need to be performed, in order to improve this first classification
L’approche paysagère dans la mise en œuvre de politiques de protection environnementale : du cadre réglementaire au projet de territoire
No full textInternational audienceNational environmental protection policies implemented in the field have an impact on complex systems such as territories. Management plans for protected areas provide guidelines but do not always directly address this question. How do these management systems change the areas concerned and how could integrating the landscape in them improve outcomes? We drew on an action research experiment to identify how protection policies are implemented in two sensitive natural areas and heritage sites in Maine-et-Loire. These sites are unique in that both their biodiversity and their landscapes are protected. This context allowed us to test the effectiveness of combining different areas of expertise and revealed the difficulty of developing a regional project that takes into consideration a variety of socio-ecological and spatiotemporal issues. In the areas studied, where stakeholders come from different professional backgrounds and have different attitudes to nature, it is difficult to explain the relevance of using the landscape to develop management systems. We will see that this approach offers the possibility of moving beyond a strictly regulatory or technical framework to identify how management choices can be implemented on sites in accordance with their spatial aspects and existing uses and based on a plan taking these uses into consideration.Les politiques nationales de protection environnementale, déclinées sur le terrain, agissent sur les systèmes complexes que sont les territoires. Les plans de gestion des aires protégées orientent leurs trajectoires, mais sans que cette question ne soit toujours traitée de façon explicite. De quelle manière ces démarches de gestion modifient-elles les espaces concernés et que pourrait apporter l’approche paysagère à celles-ci ? Nous nous sommes appuyés sur une expérience de recherche-action pour identifier comment sont mises en œuvre les politiques de protection sur deux espaces naturels sensibles et sites patrimoniaux du Maine-et-Loire. Ces sites ont en effet la particularité d’être protégés au titre à la fois de la biodiversité et du paysage. Ce contexte a permis de mettre à l’épreuve l’effectivité du croisement des expertises et a révélé la difficulté à bâtir un projet de territoire qui prenne en compte des problématiques transversales, à la fois socio-écologiques et spatio-temporelles. Sur les terrains étudiés, alors que les parties prenantes évoluent dans des cultures professionnelles différentes et des postures face à la nature non explicites et pourtant divergentes, l’intérêt de l’approche paysagère peine à être compris et mobilisé dans l’élaboration des outils de gestion. Nous verrons que celle-ci offre la possibilité de sortir du cadre strictement réglementaire ou technique pour identifier comment peuvent se concrétiser les choix de gestion : sur les sites et leurs logiques spatiales, selon un dessein pour l’avenir à préciser, et en coordination avec les usages en place
Alternatives aux néonicotinoïdes en culture de betterave : les avancées de la recherche
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Do mixed crops favour the beneficial effect of generalist predators for legume protection?
No full textInternational audienceLegumes have a high agricultural value (protein source, reduction of soybean imports, nitrogen fixation) but can be impacted by multiple arthropod pests (pea leaf weevils, bruchids or aphids).Ground-dwelling spiders and carabids are important communities of generalist predators which can play a key role in pest regulation. Their abundance and activity may be enhanced with plant diversification methods, like mixed crops.As generalists, these predators can consume multiple preys, and therefore multiple pests, providing as many regulatory services. But they can also switch from prey of agricultural interest to alternative resources. It is thus highly important to determine their consumption through direct and precise analyses. Here we investigated whether legume crop diversification can enhance biocontrol. We monitored pure (conventional and organic) vs cereal-legume organic mixed crops, analyzing the occurrence of ground-dwelling predator communities and the way they consumed preys of agricultural interest through molecular analysis of gut contents
Mapping soil carbon content in two contrasting pedoclimatic regions using a deep learning approach with remote sensing imagery and laboratory spectral datasets
No full textInternational audienceMapping soil properties can help in monitoring spatial and temporal variability in soils. However, the accuracy of predictions based on optical remote sensing data depends on the availability of cloud-free images and the presence of bare soil under suitable surface conditions. The objective of this study was to produce maps of soil organic carbon (SOC) content or soil total carbon (STC) content for two study areas with contrasting pedoclimatic conditions: Naizin (1.5 km 2 ), which has a temperate climate and mainly intensive mixed crop-livestock farms on Luvic Cambisols and Haplic Albeluvisols, and Merguellil (40 km 2 ), which has a semi-arid climate and mainly intensive farms on Fluvisols. We used a deep learning approach that combined remote sensing and laboratory visible, near-infrared and short-wave infrared (Vis-NIR-SWIR) datasets. We developed deep neural network models using all available bare soil pixels from Sentinel-2 (S2) images over one farming year and by measuring soil properties at 58 and 73 soil sampling points in the Naizin and Merguellil study areas, respectively. We used two approaches: (1) using only S2 bands to calibrate models and (2) adding laboratory spectral indices incrementally to the S2 bands in decreasing order of their correlation with SOC or STC content. To compare and analyse the spatial patterns in the SOC and STC maps produced by the two approaches, we applied one model from approach 1 and one model from approach 2. The results showed that this method was able to adapt to the two pedoclimatic contexts. Adding the laboratory indices to the models increased prediction accuracy for both study areas. Although the two approaches yielded similar spatial patterns of SOC or STC content, some differences were observed. Adding the laboratory indices increased intra-field variability in the distribution of SOC content for Naizin but decreased inter-and intra-field variability in the distribution of STC content for Merguellil. The method accurately mapped SOC content in 70 % of the Naizin area and STC content in more than 90 % of the Merguellil area. Future research could assess effects of using different methods for kriging, the potential of using hyper-spectral images for calculating spectral indices which would avoid effects of kriging on the spatial patterns in the maps of soil properties produced and the transferability of the models across different pedoclimatic region
Toward an interdisciplinarity approach to explore the local embedding of organic pig farming systems in France
No full textSession 52- Poster 19International audienceAlthough currently weak, the organic pig farming sector under Organic Farming (OF) specifications offers potential for development and for the agroecological transition of livestock farming systems in Europe. This project is based on the main barriers and levers identified in French pig production. It aims to promote a systemic approach to adding value in pork chain, and to consider the complementarities between animal and plant production at farm level, and between organic and non-organic farming sectors at regional level. The question addressed is how the local anchoring of organic pig farming contribute to the transition of local agri-food systems. The objectives of the project are to establish a method for analysing the role of organic pigs in localized food systems, integrating both the farm and regional levels and to test it in contrasted French territories. The project brings together researchers and academic staff with expertise in technical sciences as well as human and social sciences. Different dimensions will be emphasized, such as natural environments, interaction and cooperation between stakeholders, territorial resources, valorisation of products and coproducts and the link between animal and plant production for human nutrition. Three stages will be followed: (1) definition of conceptual and theoretical frameworks to build interdisciplinarity, (2) design and testing of the approach in three regions of France, and (3) synthesis and dissemination of the results. The approach will be communicated to students, stakeholders from both organic and non-organic sectors, policymakers and scientists
Association between growth profiles of Holstein heifers and their longevity
No full textInternational audienceIn many studies, early calving is more profitable than late calving in Holstein dairy heifers. However, with a first calving at 24 months old, the growth profile might influence subsequent performance and longevity. The association between Holstein heifers’ growth profiles and their future longevity was analyzed in present study. Data originated from 3 French experimental farms and included heifers born from 2000 until 2019. Only animals firstly inseminated before 19 months of age and weighed at least 5 times from birth to 19 months of age were kept in the analyses. Growth profiles were then determined on 1217 Holstein heifers. Insemination and successive calving dates, 305 days milk yield, 305 days fat plus protein and culling date were available. Growth profile groups between birth and 365 d of age were established using a principal component analysis (PCA) on 6 variables: body weight (BW) at birth, at 70 d, at 120 d, at 180 d, at 275 d and at 365 d of age. Then, a hierarchical ascendant classification was performed on the axes 1 to 3 of the PCA. Four types of growth profiles were identified. Heifers in the slow-growth profile had a later age at first calving and a lower first calving rate compared with heifers in the high growth profile (+43 d and -3 points, respectively). These animals also presented a lower 305d milk yield and 305d milk solids yield during lactation one (-697 kg and -48 kg, respectively). However, percentage of second lactating cows did not differ among growth profiles. All profiles had similar performance regarding age at culling, length of productive life i.e; from 1st calving to culling, and lifetime milk yield. Growth profile affected performance duringearly life (before 1st and during 1st lactation) but not longevity. However, results from present study confirmed that achieving higher growth performances from birth to one year of age is of interest in Holstein dairy heifers, since age at first calving is reduced, and both first calving rate and first lactation productivity are improved