Most farming systems in semi-arid West Africa rely on organic matter recycling for maintaining soil fertility. The cycling of biomass through ruminant livestock into dung (faeces) and urine that fertilize the soil has long been an important factor in t he nutrient cycling processes of these integrated, mixed crop/livestock systems. While dung greatly improves soil properties and crop yields, little is known about the effects of urine on soil chemical properties and the impact of dung and urine on crop p roduction. An average voiding of sheep urine applied to a sandy, siliceous soil in the Republic of Niger increased soil pH, available phosphorus and ammonium levels dramatically in the upper 10–15 cm of soil, especially during the first week following application. Losses of applied urine nitrogen via volatilization were in the order of 30–50%. A four-year field trial was conducted on the same soil type to evaluate the effects on pearl millet and weed yields of corralling cattle o r sheep overnight on cropland (dung plus urine application) for one, two or three nights, every one, two or three years versus the effects of applying only dung at the same application rates and intervals achieved with corralling. The main results of this field trial were that (1) urine had large positive effects on millet grain, threshed panicle, leaf, stem and weed yields, (2) sheep dung was more effective than cattle dung in increasing yield, (3) two nights of dung application was adequate for maximum yield and (4) the positive effects of dung and urine on yield lasted two to three cropping seasons after application.