Effects of dietary nitrogen source fed to steers on faecal nitrogen, its mineralization and the vegetative responses in maize to the incorporation of the faeces in soil
1999
Delve, R.J. (University of London, Kent (UK). Wye College) | Tanner, J. (International Livestock Research Institute, Nairobi (Kenya)) | Kimani, S. (Kenya Agricultural Research Institute, Nairobi (Kenya)) | Giller, K.E. | Cadisch, G. (University of London, Kent (UK). Wye College) | Thorne, P.J. (Natural Resources Institute, Kent (UK))
Different quality faeces (i.e. varying in total N, soluble N content and N bound to fibre), were produced by feeding cattle a barley straw basal diet alone or supplemented with 15% or 30% C. calothyrsus, M. axillare or poultry manure. Faeces derived from supplementation with C. calothyrsus and M. axillare resulted in shorter nitrogen immobilization in leaching tubes (16 weeks) than supplementation with poultry manure (24 weeks) when compared with faeces derived from animals fed straw only (28 weeks). The consequences of this initial immobilization of faeces N were illustrated by a glasshouse experiment in which reductions in dry matter yields from l0 week old maize seedlings of between 6 and 27% were observed in pots to which faeces had been added. Although, after reseeding the same pots for a second 10 week growth period larger dry matter yields were observed (20% to 91 %) in pots where faeces had been added compared with the soil only control. Overall, the cumulative yields showed no significant treatment differences on dry matter yield. Clearly the time lag between faeces application and subsequent N release has implications for planning organic matter applications to soil, these results also suggest that dietary factors might need to be taken into account in doing this.
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