ISBN 9783843912013

978-3-8439-1201-3, Reihe Agrarwissenschaften

Beate Formowitz
Causes of legume rotation induced yield increases in cereals grown on West African soils

113 Seiten, Dissertation Universität Kassel (2013), Softcover, A5

Zusammenfassung / Abstract

In West Africa, where agricultural production is very limited and restricted to a short rainy season, the introduction of legume rotations presents a promising complement within a holistic soil fertility management approach to intensify the local agricultural production. In previous experiments under field conditions, the preceding cultivation of cowpea (Vigna unguiculata Walp) and groundnut (Arachis hypogea L.) led to yield increases in the succeeding cereals (Pennisetum glaucum L.; Sorghum bicolor Moench; Zea mays L.), increased soil pH, early mycorrhizal infection and decreased the number of phytoparasitic nematodes. Additionally, indicators for a specific shift in the microbial community structure were found, but still these changes are not fully understood.

This study was therefore conducted to investigate soil biological and chemical factors that give rise to the cereal yield enhancing effects of legume rotations on sandy, nutrient poor West African soils. The aim was not only to gain more information on the role of legume residues and microorganisms in the soil nutrient cycle. But the study aimed at evaluating if differences in substrate qualities (e.g. root residues) cause changes in the microbial community structure due to specific and highly complex microbe-root-soil interactions.

The comparison of continuous cereal (CC) and cereal legume rotation (CL) soils from two West African sites (Fada-Kouaré in Burkina Faso, F, and Koukombo in Togo, K) allowed to confirm assumptions of previous studies that site and system specific differences in soil chemical and biological parameters play an important role in explaining the yield increasing effects of legume rotations.