Research Article The Effects of Some External Management Factors on the Nitrogen Composition of Cattle Manure on Smallholder Farms

Copyright © 2012 H. A. Markewich et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Smallholder farmers in Kenya collect manure from confined cattle housing termed zero-grazing units. Zero-grazing designs may include urine collection, though the effectiveness of these designs in improving manure N content has not been established. The manure-urine mixtures produced in these units were simulated to determine urine effects on manure N composition. Manure and manure-urine mixtures were stored for 120 days during dry and rainy seasons in Kenya. Manure-urine mixtures leached 26 % of their mineral N content during the dry season, but only 12 % during the rainy season. After storage, manure-urine mixtures had less organic-N and fiber-N than manure alone during the dry season (P < 0.01), but not during the rainy season. Results suggest that the effect of cattle urine on manure N composition is greater during dry seasons than rainy. Manure should not be stored more than 30 days to minimize N loss to leaching. Farmers may take steps to reduce N loss by controlling leaching and protecting manure from rainfall. 1