Soil organic matter dynamics in tiger bush (Niamey, Niger). Preliminary results

摘要: Abstract Some typical features of soil organic matter dynamics and texture were studied to discuss the particular spatial pattern tiger bush in Niger its dynamics. The through silt clay contents showed a high variability vegetation arc as well bare area. These variations clearly linked water/wind erosion termite activity. Tiger soils capacity store despite moderate primary production, even area where input plant debris has been nil for many decades. carbon content was higher within (0.93 %) than (0.45 %). Additionally, potential mineralisation significantly varied relation total thus production. Then, arcs can be viewed `fertility islands' arid ecosystems. measurements δ 13 C dominant contribution 3 plants pool. Nevertheless, 4 not negligible. Two hypotheses could proposed: different rate between plants; or (ii) better physical protection compounds against biodegradation. variables depending totally partly on biological factors, such nitrogen contents, isotopic composition, mineralisation, did show any symmetry their along transects. It expected because cover does specific composition structure. In area, clear asymmetry observed some variables: content, fine material natural abundance C. This supports hypothesis that move upslope, weakens alternance contraction spreading periods cover.