The purpose of this study was to improve knowledge on the evaluation of the ecological value of a plant formation. This process includes several stages including the definition of the evaluation objective, the inventory of the environment or data collection, the choice of criteria, the rating of the criteria, the calculation of the weighting by criterion and the total weighting and finally, the evaluation of the ecological value of the site. he practical case of the Mamadou Sangaré estate shows that denser and richer forest formations record a higher ecological value compared to savannah formations.

Agro- economic performance of the micro- dose fertilizer on intercropping in the cotton belt of western Burkina Faso. The cotton zone of Western Burkina Faso, is characterized by a reduction of land reserves and soil fertility. Innovations techniques from hybridization of scientific and local knowledge have been tested in this zone. This paper describes the approach and gives experimental results on the diversity of cultural practices between the maize-mucuna and the maize-pigeon pea association and the effects of using micro-dose of fertilizer on the agronomic and economic performance of the two type of crop association. The study was conducted in 2012 with 36 farmers in two villages of the municipality of Koumbia (Burkina Faso). Mineral fertilizers were applied on the maize associated according to the conventional requirements (150 kg ha-1 NPK and 50 kg ha-1 urea) and micro-dose (75 kg ha-1 of NPK and 50 kg ha-1 urea). The results show that the time of planting, crop densities and the residual effects of previous crops are the factors of variation in associating maize-mucuna and maize-pigeon pea. It has been also noted that the micro-dose induces a non-significant increase in grain yield of maize 4 and 11% respectively for the maize-pigeon pea and maize-mucuna, compared to a broadcast application. Economic performance and the work time between micro-dose and broadcast application are not significantly different (p < 0.05). In a context of scarcity of agricultural land, the results of this study show that the maize-legume associations allow a diversification of production on the same unit area and ensure food and forage safety.