Weeds control through tree-crop associations in a parkland of Burkina Faso

Abstract

The effects of microclimate due to tree presence on weeds development were assessed under Baobab (Adansonia digitata) and Néré (Parkia biglobosa) in a parkland in Nobéré (Burkina Faso). In association with these trees, two crops were grown: a shade tolerant crop (Colocasia esculenta, taro) and a shade intolerant cereal (Pennisetum glaucum, Millet). Weeds species and biomass production were assessed in a plot (0.5m X 0.5 m) in three concentric zones around tree trunk (A, B and C) and in the open field (H). Shannon's diversity index was calculated for each zone of both tree species and both crops. Seventy-six (76) weeds species from nineteen (19) families were recorded on the parkland from which only 13 families were found in the open field. Then, weeds floristic composition was more diversified in area beneath both trees species compared to the open field. The most represented weeds family in the open field was Poaceae while under both tree species, the most recorded species were from Amaranthaceae family. In addition, more weeds species were associated with Néré tree (58 species) compared with baobab tree (48 species). The number of weeds species increased from Néré tree trunk (17) to the surrounding area of the edge of tree crown (25) in contrast of baobab tree associated with taro (16 and 6, beneath trunk and crown edge, respectively). Moreover, growing taro under tree crown reduced the number of weeds species and also weeds development (low biomass production) under tree crown compared with millet. Therefore, introducing a shade tolerant crop as taro in parkland agroforestry system could help farmers to control weeds under trees in their farms.

Keywords: Adansonia digitata, Colocasia esculenta, Parkia biglobosa, Parkland agroforestry system, Pennisetum glaucum, weeds floristic composition.