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Current knowledge and future research opportunities for modeling annual crop mixtures. A review
No full textGrowing mixtures of annual arable crop species or genotypes is a promising way to improve crop production without increasing agricultural inputs. To design optimal crop mixtures, choices of species, genotypes, sowing proportion, plant arrangement, and sowing date need to be made but field experiments alone are not sufficient to explore such a large range of factors. Crop modeling allows to study, understand and ultimately design cropping systems and is an established method for sole crops. Recently, modeling started to be applied to annual crop mixtures as well.
Here, we review to what extent crop simulation models and individual-based models are suitable to capture and predict the specificities of annual crop mixtures. We argued that: 1) The crop mixture spatio-temporal heterogeneity (influencing the occurrence of ecological processes) determines the choice of the modeling approach (plant or crop centered). 2) Only few crop models (adapted from sole crop models) and individual-based models currently exist to simulate annual crop mixtures. 3) Crop models are mainly used to address issues related to crop mixtures management and to the integration of crop mixtures into larger scales such as the rotation, whereas individual-based models are mainly used to identify plant traits involved in crop mixture performance and to quantify the relative contribution of the different ecological processes (niche complementarity, facilitation, competition, plasticity) to crop mixture functioning.
This review highlights that modeling of annual crop mixtures is in its infancy and gives to model users some important keys to choose the model based on the questions they want to answer, with awareness of the strengths and weaknesses of each of the modeling approaches
Contribution of plant diversity to farmers' income in cocoa-based agroforestry systems
No full textThe diversity of associated crops within cocoa-based agroforestry systems (CAFS) generates different productions that can be either sold or self-consumed. This wide range of plant species and densities directly influence the amounts of products to be sold and/or self-consumed by the producers and their families. Consequently, the impacts on the overall economic performances of these CAFS can be important but have been poorly assessed. We characterized 140 CAFS distributed over 3 production areas in the Dominican Republic in order to (i) build a typology of Dominican CAFS according to their cultivated plant structure, and (ii) compare the agro-economic performances of each type of CAFS. We found that the sum of the different sales, including cocoa, do not differ significantly among the 3 types of CAFS that we characterized. However, a high degree of diversification combined with a significant densification of associated fruit species weakens the economic performance of cocoa sales, but increases fruit sales and the level of self-consumption of the farming household. On the other hand, a low diversification of plants associated with nitrogen-fixing trees increases the economic performance linked to the sales of cocoa but reduces fruit sales and self-consumption. This study evidences different farmer’s strategies. It also provides elements for the improvement of agricultural practices towards different economic options between sold and self-consumed products provided by CAFS
Spodoptera frugiperda immune response to the nematobacterial complex Steinernema carpocapsae-Xenorhabdus nematophila
No full textTranscriptional profiling and pathway analysis reveal differences in pituitary gland function, morphology, and vascularization in chickens genetically selected for high or low body weight.
No full textThough intensive genetic selection has led to extraordinary advances in growth rate and feed efficiency in production of meat-type chickens, endocrine processes controlling these traits are still poorly understood. The anterior pituitary gland is a central component of the neuroendocrine system and plays a key role in regulating important physiological processes that directly impact broiler production efficiency, though how differences in pituitary gland function contribute to various growth and body composition phenotypes is not fully understood. Global anterior pituitary gene expression was evaluated on post-hatch weeks 1, 3, 5, and 7 in male broiler chickens selected for high (HG) or low (LG) growth. Differentially expressed genes (DEGs) were analyzed with gene ontology categorization, self-organizing maps, gene interaction network determination, and upstream regulator identification to uncover novel pituitary genes and pathways contributing to differences in growth and body composition. A total of 263 genes were differentially expressed between HG and LG anterior pituitary glands (P ≤ 0.05 for genetic line-by-age interaction or main effect of line; ≥1.6-fold difference between lines), including genes encoding four anterior pituitary hormones. Genes involved in signal transduction, transcriptional regulation, and vesicle-mediated transport were differentially expressed and are predicted to influence expression and secretion of pituitary hormones. DEGs involved in immune regulation provide evidence that inflammation and response to cellular stressors may compromise pituitary function in LG birds, affecting their ability to adequately produce pituitary hormones. Many DEGs were also predicted to function in processes that regulate organ morphology and angiogenesis, suggesting pituitary gland structure differs between the divergently selected lines. The large number of DEGs within the anterior pituitary gland of birds selected for high or low body weight highlights the importance of this gland in regulating economically important traits such as growth and body composition in broiler chickens. Intracellular signaling, transcriptional regulation, and membrane trafficking are important cellular processes contributing to proper hormone production and secretion. The data also suggest that pituitary function is intimately tied to structure, and organization of the gland could influence hypothalamic and systemic metabolic inputs and delivery of hormones regulating growth and metabolism into peripheral circulation
Automatic high-frequency measurements of full soil greenhouse gas fluxes in a tropical forest
No full textMeasuring in situ soil fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) continuously at high frequency requires appropriate technology. We tested the combination of a commercial automated soil CO2 flux chamber system (LI-8100A) with a CH4 and N2O analyzer (Picarro G2308) in a tropical rainforest for 4 months. A chamber closure time of 2 min was sufficient for a reliable estimation of CO2 and CH4 fluxes (100% and 98.5% of fluxes were above minimum detectable flux - MDF, respectively). This closure time was generally not suitable for a reliable estimation of the low N2O fluxes in this ecosystem but was sufficient for detecting rare major peak events. A closure time of 25 min was more appropriate for reliable estimation of most N2O fluxes (85.6% of measured fluxes are above MDF +/- 0.002 nmol m(-2) s(-1)). Our study highlights the importance of adjusted closure time for each gas
Feminist political ecologies of the commons and commoning (Editorial to the Special Feature)
No full textUltrastructural mapping of salivary gland innervation in the tick Ixodes ricinus
No full textThe salivary gland of hard ticks is a highly innervated tissue where multiple intertwined axonal projections enter each individual acini. In the present study, we investigated the ultrastructural architecture of axonal projections within granular salivary gland type II and III acini of Ixodes ricinus female. Using immunogold labeling, we specifically examined the associations of SIFamide neuropeptide, SIFamide receptor (SIFa_R), neuropeptide pigment dispersing factor (PDF), and the invertebrate-specific D1-like dopamine receptor (InvD1L), with acinar cells. In both acini types, SIFamide-positive axons were found to be in direct contact with either basal epithelial cells or a single adlumenal myoepithelial cell in close proximity to the either the acinar duct or its valve, respectively. Accordingly, SIFa_R staining correlated with SIFamide-positive axons in both basal epithelial and myoepithelial cells. Immunoreactivity for both InvD1L and PDF (type II acini exclusively) revealed positive axons radiating along the acinar lumen. These axons were primarily enclosed by the adlumenal myoepithelial cell plasma membrane and interstitial projections of ablumenal epithelial cells. Our study has revealed the detailed ultrastructure of I. ricinus salivary glands, and provides a solid baseline for a comprehensive understanding of the cell-axon interactions and their functions in this essential tick organ
Wanting and spontaneous intake for protein-rich foods immediately after hemodialysis in chronic kidney disease patients
No full textHow to assess FAIRness to improve crediting and rewarding processes for data sharing? A step forward towards an extensive assessment grid.
No full textThe SHARC (SHAring Reward & Credit) interest group (IG) is an interdisciplinary group set up in the framework of RDA (Research Data Alliance) to improve crediting and rewarding mechanisms in the sharing process throughout the data life cycle. Notably, one of the objectives is to promote data sharing activities in research assessment schemes at national and European levels. To this aim, the RDA-SHARC IG is developing assessment grids using criteria to establish if data are compliant to the FAIR principles (findable /accessible / interoperable / reusable).
The grid is aiming to be extensive, generic and trans-disciplinary. It is meant to be used by evaluators to assess the quality of the sharing practice of the researcher/scientist over a given period, taking into account the means & support available over that period. The grid displays a mind-mapped tree-graph structure based on previous works on FAIR data management (Reymonet et al., 2018; Wilkinson et al., 2016; Wilkinson et al., 2018; and E.U.Guidelines about FAIRness Data Management Plans). The criteria used are based on the work from FORCE 11*, and the Open Science Career Assessment Matrix designed by the EC Working group on Rewards under Open science. The criteria are organised in 5 clusters: ‘Motivations for sharing’; ‘Findable’, ‘Accessible’, ‘Interoperable’ and ‘Reusable’. For each criterion, 4 graduations are proposed (‘Never / Not Assessable’; ‘If mandatory’; ‘Sometimes’; ‘Always’). Only one value must be selected per criterion. Evaluation should be done by cluster; the final overall assessment will be based on the sum of the number of each ticked value / total number of criteria in each cluster; the ‘motivations for sharing’ should be appreciated qualitatively in the final interpretation. The final goals are to develop a graduated assessment of the researcher FAIRness literacy and help identifying needs to build FAIRness guidelines to improve the sharing capacity of researchers
Effect of starch substitution by rapeseed oil on enteric methane emission and performance in dairy cows fed grass-silage based diets
No full textThis work aimed to study the effect of energy source supplementation on methane emission and performance in dairy cows fed grass-silage based diets.
Eight multiparous lactating Holstein cows were used in a replicated 4 x 4 Latin square design with 4 periods of 28 days. Animals were limited fed (95% ad libitum) with 4 grass silage based diets supplemented with 4 concentrates in which starch was gradually substituted by increasing amounts of rapeseed oil (1.5, 3.0 and 4.5% on a dry matter basis). Diets were formulated to be iso-energy and iso-protein to meet individual energy and protein requirements for production. Methane emissions were measured (days 23 to 27) when animals were in open-circuit respiration chambers. Daily intake, milk production and composition were also recorded.
Intakes of gross energy and fiber were similar among diets, starch intakes decreased linearly (P < 0.0001) and ether extract intake increased linearly (P < 0.001) with increasing rapeseed oil amounts. Methane emissions (g/d), yield (g/kg dry matter intake) and intensity (g/kg milk) decreased linearly (P < 0.01) when starch was replaced by rapeseed oil in the diets.
Milk production and composition differ among diets (P < 0.001). The linear decrease in milk fat yield with increasing amounts of oil suggests a milk fat depression with changes in milk fatty acids profile. Starch substitution by rapeseed oil decreased both enteric methane emission and performance in dairy cows fed grass-silage based diets