Etude de l'arrière-effet de l'enfouissement de différentes substances organiques en vue de l'amélioration de sols ferrugineux dégradés

Study of the backward effect of the burying of different organic substances with a view to the improvement of degraded ferruginous soils. With the help of a se ries of incubation in vitro, we have proved, the weak of a peat and the "starter" effect of poultry droppings mixed with this peat. Trials in the open fields allowed us to study the interaction between peat and other substances biologically more active namely poultry droppings, groundnut-tops and horse manure. The first year of the experimentation, the results showed the depressive action of the peat on account of the increase of the reorganization of nitrogen andphosphorous. Nevertheless, the results of the following rainy season (1987) (Study of backward effect) show the disappearance of the depressive effect of the peat. As a matter of tact we have noticed no important difference between the treatments enriched by only falling substances (droppings and tops) and those enriched by a mixture (peat x tops). The results of the 1988 rainy season put the stress on the lasting quality of the residual effect of the peat, because the yield of the treatment (B) enriched only by peat is placed at the same level as the yield after the contribution of groundnut-tops and it is significantly superior at the 5 % level to that of poultry droppings

Effet de Leucaena leucocephala, des fientes de volaille ou du fumier de bovins sur la productivité du maïs cultivé sur "terre de barre" au sud Bénin

Effect of Leucaena leucocephala, Poultry Manure or Cattle Manure on Maize Productivity on Feralitic Soil "terre de barre" in South Benin. Our work has consisted on the study of post-effect of Leucaen's prunings and poultry manure buried last year and also on the study of the direct effect of cattle manure and its interaction with Leucaen's pruning on maize productivity on feralitic soil "terre de barre". - The mixture of Leucaen's prunings and poultry manure had positive post-effect giving a yield of fresh ears and grains significantly higher (9 %) to the reference and other treatments in the plots over the alley. - The supply of 5 t/ha of cattle manure appears insufficient. On the other hand the mixture of Leucaen's prunings and cattle manure gave the best results related to the soil's properties such as organic matter's content or total exchange capacity of the soil and also concerning the yields. In this case we notice that ail the results are significantly higher to the other treatments. These results emphasize the importance of a supply of organic matter's to the soil thereby fertilizing it in humus and mineral elements

Influence des amendements calcaire et organique sur le rendement de l'arachide en sol acide dégradé au Sénégal

The influence of organic and calcareous amendments on yield of groundnut produced on acid degrated soils, in Senegal. Trials were carried out during the 1984 and 1985 seasons to determine the influence of organic matter and liming on low feriility acid soils using groundnuts as an indicator. Results indicated that groundnuts have a wide tolerance to variation in pH. Horse manure applied in 1984 had a significant influence on yield, reduced the rate of plant mortality, and had a positive residual effect in 1985. Peat mixed with either manure or commercial fertilizer increased yield, but to a lesser extent than manure alone because of its specific characteristics however, further testing of these treatments is under way

Effet de la substitution d'essence sur le fonctionnement et la durabilité des écosystèmes forestiers : l'apport des travaux pluridisciplinaires menés en forêt de Breuil Chenue - Morvan

National audienceLe site-atelier de Breuil (Morvan), appartenant à l’Observatoire de Recherche sur l’Environnement F-ORE-T, est un support opérationnel des travaux actuels sur les cycles biogéochimiques en relation avec la diversité biologique du sol. De nombreux projets multidisciplinaires sont en cours sur ce site dont l’objectif commun est d’améliorer les connaissances sur les effets physiques, chimiques et biologiques des substitutions d’essences. Des travaux y sont menés à différentes échelles temporelles et spatiales, de l’instantané au pluriannuel, du microsystème fonctionnel jusqu’à l’écosystème complet. Les travaux développés à Breuil depuis 2001, montrent que les essences ont affecté les cycles clé du carbone et de l’azote avec les conséquences sur le fonctionnement des cycles de tous les autres éléments. Ces modifications sont entre autres liées à un contrôle des populations de micro-organismes du sol par les essences forestières qui les structurent. Les recherches en cours tentent d’élucider cette question pertinente d’écologie. Compte tenu de la longévité des essences forestières, ce site devra être suivi sur le long terme, vraisemblablement par une approche diachronique