Effet des réserves de taillis sous futaie sur la croissance du taillis. Étude préliminaire

L'influence de la présence d'un arbre de réserve sur la croissance du taillis est étudiée dans le cas d'un peuplement de taillis sous futaie pauvre en réserve de la forêt domaniale d'Orléans (Loiret), selon un dispositif à 3 répétitions. Les réserves sont des chênes pédonculés (Quercus robur L) dominant un taillis de charme (Carpinus betulus L), âgé de 40 à 50 ans. Les principales variables prises en compte sont la surface terrière, le nombre de brins et le nombre de cépées du taillis. L'influence globale individuelle d'une réserve sur la croissance d'une cépée donnée n'est pas décelable. On a, en revanche, mis en évidence un effet dépressif significatif sur la surface terrière du taillis, particulièrement à moins de 5 m de la réserve, ainsi qu'une influence sur le mode de répartition des cépées autour de l'arbre selon les points cardinaux. Les autres tendances observées ne sont pas significatives en intensité, mais plusieurs sont répétitives dans plus de 50 % des cas. Ces premiers résultats mériteraient d'être précisés dans le cadre d'un dispositif plus grand prévoyant plusieurs espèces de taillis et une bonne connaissance de la variabilité du sol.Effect of standards on coppice growth in coppice-with-standards. Preliminary results. The influence of standards remaining for several coppice rotations, on the growth of the copice understorey, was studied in the Forêt d'Orléans (Central France). Oak standards (Quercus robur L) dominated a 40-50 year old hornbeam (Carpinus betulus L) coppice. The trial comprised 3 replicates. The main stand variables measured were basal area, number of sprouts and number of stools. No influence of a standard on individual stool growth could be shown. A significant negative effect on coppice basal area was observed, closer than 5 m from the standard, as well as an influence on stool distribution around the standard. Other tendencies were not statistically significant, but several of them are repetitive. These initial results need to be validated further on larger trials taking into account several coppice species with detailed information on soil variability

La prospective "Grandes Cultures" en Midi-Pyrénées, une démarche originale permettant d'articuler évolutions globales et dynamiques locales de changement

National audienc

Participatory methodology for designing an agroecological transition at local level

The purpose of the TATA-BOX project was to develop a toolbox to sup-port local stakeholders in the design of an agroecological transition at local level. A participatory process based on existing conceptual and methodological frameworks was developed for the design of new configurations of stakeholders and resource systems in the farming systems, supply-chains and natural resources management that were to form a new agroecological territorial system. This process, presented here, was adapted and tested on two adjacent territories in south-western France. It was structured around three main stakeholders’ workshops to support the holistic diagnosis, the design of a normative vision, and the backcasting approach of the transition pathway. We describe the participatory methods and the multimodal inter-mediary tools used to support the collective design of the agroecological transition. We also present the main turnkey outcomes of the design process for local stake-holders, including shared diagnosis, vision for an agroecological territorial system in 2025, and a projected action plan for transition from the initial to the desired agriculture and associated governance structures. Finally, we discuss the limits of the process and the conditions that would enable stakeholders to implement the transition, by reducing remaining uncertainties

Effects of nurse shrubs and tree shelters on the survival and growth of two Austrocedrus chilensis seedling types in a forest restoration trial in semiarid Patagonia, Argentina

International audienc

Relações entre cátions trocáveis do solo e suas correlações com a qualidade de frutos de melão Soil cationic ratios and its correlation with melon fruit quality

A qualidade dos frutos de melão pode ser prejudicada pelo excesso de nutrientes no solo e pelo desequilíbrio entre eles, causados por adubações excessivas e desuniformes. A amostragem em duas áreas de produção de melão foi realizada para identificar entre relações catiônicas do solo (K:(Ca+Mg), K:Ca, K:Mg, K:CTC, Ca:Mg, Ca:CTC, Mg:CTC, Na:Ca, Na:Mg e PST) aquelas melhor correlacionadas com características de qualidade (espessura de polpa, firmeza da polpa e teor de sólidos solúveis totais). Para tanto se utilizou a estatística descritiva, o coeficiente de correlação de Spearman e a regressão múltipla. As variáveis de qualidade de frutos de melão apresentaram poucas correlações com as relações catiônicas do solo. No Goldex, as melhores correlações foram de K:CTC com espessura de polpa; Ca:CTC e Mg:CTC com firmeza de polpa e K:CTC, K:Ca, K:(Ca+Mg), Na:Ca e Na:Mg com SST, todas positivas. No Orange Flesh, observaram-se correlações apenas de firmeza de polpa com Ca:CTC (positiva), K:Mg, K:Ca, K:(Ca+Mg) e Na:Ca (negativas). No Orange Flesh, através da contribuição para as regressões, identificou-se como mais importantes as relações catiônicas Ca:CTC para espessura (6,2%) e firmeza de polpa (10,9%), e Mg:CTC para o teor de sólidos solúveis totais (1,5%).<br>Melon fruit quality can be reduced by soil nutrient excess and imbalance, both caused by excessive and non uniform fertilizations. Soil samples were taken from two melon fields aiming to identify, among soil cationic ratios (K:(Ca+Mg), K:Ca, K:Mg, K:CTC, Ca:Mg, Ca:CTC, Mg:CTC, Na:Ca, Na:Mg, and ESP), those better correlated with fruit quality characteristics (pulp thickness, pulp firmness and total soluble solids (SST)). Descriptive statistics, Spearman's correlation and multiple regressions were used in the analysis. Melon fruit quality characteristics presented few correlation with soil cationic ratios. In Goldex, the best correlation found were of K:CTC with pulp fruit thickness; Ca:CTC and Mg:CTC with pulp firmness and of K:CTC, K:Ca, K:(Ca+Mg), Na:Ca and Na:Mg with SST, all positive. In Orange Flesh, only pulp firmness showed correlation with Ca:CTC (positive), K:Mg, K:Ca, K:(Ca+Mg) and Na:Ca (negative). On the basis of their contribution to regressions in Orange Flesh, cationic ratios identified as more important were Ca:CTC for pulp fruit thickness (6,2%) and pulp firmness (10,9%), and Mg:CTC for total soluble solids (1,5%)