Decomposition and nitrogen release patterns of shrubs/trees leafy biomass in the Sahelian zone of Senegal in West Africa
Siriki Fane1, Deogratias Kofi Agbotui1, Cheikh Ndiaye2, Mariko Ingold1, Sophie Graefe1, Andreas Buerkert1
1University of Kassel, Organic Plant Production and Agroecosyst. Res. in the Tropics and Subtropics, Germany
In open-parkland systems of the West African Sahel, farmers often apply leafy plant biomass to their croplands to maintain soil productivity. Nonetheless, there is a need for research that examines how shrub and tree leaf biomass decompose and mineralize to better understand processes of nutrient cycling in these agroecosystems. The present study therefore aims at monitoring decomposition and nitrogen (N) release of leafy biomass of selected shrub and tree species from the region. Using the litterbag technique, our study was conducted in the Louga Region of Senegal with leaves of Faidherbia albida (Delile) A.Chev., Pterocarpus lucens Lepr., Guiera senegalensis J. F. Gmel., and Piliostigma reticulatum (DC.) Hochst. Each litterbag was filled with 26 g of leaves which were placed on the soil surface and sampled at weeks 2, 4, 8, and 16. Decomposing leaves lost on average 30 % of their initial dry weight in the first four weeks after placement. At weeks 2, 4, 8, and 16, DM losses of F. albida were with 43 %, 43 %, 51 %, and 44 %, respectively, significantly (p < 0.05) larger than those of G. senegalensis. Only at week 2 average N releases of F. albida and P. lucens were significantly (94%, p < 0.05) higher than of G. senegalensis and P. reticulatum. Nitrogen fixing trees and shrubs species (F. albida and P. lucens) had a higher decomposition and nitrogen release because of their lower C/N ratios. To improve application efficiency for crop yields, use of mulched leaves should be tailored depending on the type of leafy biomass to optimize synchronization of nutrient release with crop nutrient demands.
Keywords: Agroforestry, litter quality, litterbag technique, nutrient cycling, organic agriculture
Contact Address: Siriki Fane, University of Kassel, Organic Plant Production and Agroecosyst. Res. in the Tropics and Subtropics, Steinstr. 19, D-37213 Witzenhausen, Germany, e-mail: siriki.fanemesrs.ml