PHOTOSYNTHESIS AND BIOMASS PRODUCTION BY MILLET (PENNISETUM GLAUCUM) AND TARO (COLOCASIA ESCULENTA) GROWN UNDER BAOBAB (ADANSONIA DIGITATA)AND NÉRÉ (PARKIA BIGLOBOSA) IN AN AGROFORESTRY PARKLAND SYSTEM OF BURKINA FASO (WEST AFRICA)

SUMMARYPhotosynthesis and biomass production by millet (Pennisetum glaucum) and taro (Colocasia esculenta) grown under baobab (Adansonia digitata) and néré (Parkia biglobosa) was studied at Nobéré (Burkina Faso) with the aim of optimising parkland systems productivity. Millet yielded the highest biomass under Baobab and the lowest biomass was recorded in the zone close to the tree trunk of néré. In contrast, the biomass of taro was higher in heavy shaded zones under néré and the zone close to baobab's trunk. The two crops showed an increasing trend of photosynthesis rate (PN) from tree trunk to the open area. However, the increase in thePNof taro from tree trunk to the open field was lower compared to that of millet. By increasing its leaf area index (LAI) under shade, taro displayed higher biomass production under tree compared to the open area while an opposite trend was observed in millet. The high millet biomass production under baobab could be explained by light availability and the reduction of temperature under shade compared to the open field. The adaptation of taro to shade by increasing its LAI and thus avoiding drastic reduction inPNunder shade resulted in better biomass production under heavy shade. Therefore, it was concluded that by replacing millet with taro under dense tree crowns the productivity of agroforestry parkland systems could be increased.

Facteurs socio-économiques influençant la biodiversité ligneuse des parcs agroforestiers de deux villages du plateau central du Burkina Faso | Influence of socioeconomic factors on the biodiversity of woody species in agroforestry parkland systems: A case study in two villages in the central plateau of Burkina Faso

Agroforestry parklands face strong pressure from the increasing population of the region. The World Agroforestry Centre (ICRAF Sahel) started a biodiversity project with the objective of developing methods to conserve biodiversity and to improve the situation of the poor rural population. In this context the present study examined the influence of land use unit and the prosperity classes of farmers on the biodiversity of woody species. A wealth ranking classification was carried out and applied to the households of two villages in the central plateau of Burkina Faso using the "Participatory Analysis of Poverty and Livelihood Dynamics" (PAPoLD) method. Thirty farmers of different prosperity classes were chosen and inventories carried out on their different land use units. Statistical analyses show an increase in biodiversity from the village housings. However, no significant influence on biodiversity was observed in connection with a farmer's prosperity class.