Leaf biomass modeling, carrying capacity and species-specific performance in aerial fodder production of three priority browse species Afzelia africana, Pterocarpus erinaceus and Daniellia oliveri in Benin

摘要

Browse plants play an important role in feeding ruminants especially in dry seasons when herbaceous forage is unavailable. This paper aim at developing models for leaf biomass estimating for their rapid evaluation and the planning of the rational use conditions. For each of the three main browse species, 25 trees were sampled. Dendrometric measurements such as girth at breast height, total height, stem height, crown diameter and crown height were performed on each tree before harvesting the entire leaf biomass which is then weighed. A sample of 200 g of leaves was taken per tree to estimate the dry matter. Kruskal-Wallis test was performed to compare plant traits among the three species. Relationship between plant traits and aerial fodder biomass was examined using a stepwise multiple regression. Carrying capacity was determined for the dry season in the study area. Aerial fodder production varied among species. The best models that estimated leaf biomass production of Afzelia africana and Pterocarpus erinaceus were obtained with diameter at breast height, a plant trait not directly affected by pruning as predictor. For Daniellia oliveri the best model uses the crown height as estimator parameter. Globally, the carrying capacity of each species is about 0.05 to 0.09 TLU/ha/year for Afzelia africana; 0.03 to 0.08 TLU/ha/year for Pterocarpus erinaceus and 0.04 to 0.79 TLU/ha/year for Daniellia oliveri inin the dry season. The number of animal that can sustainably be fed in the study area was 38497. The introduction of these fodder tree species in afforestation/reforestation activities can improve the availability of leaf biomass to feed animals.