Upgrading wheat straw with urea at a tropical temperature: effects of urea concentration and amount of solution on in vitro digestibility and pH

Extension literature on upgrading straws in the tropics (e.g. Schiere and Ibrahim, 1989) advocates applying 1 kg of 40 g/kg urea solution per kg air dry straw and storing under plastic for 4 weeks. Surprisingly, there is little published information on responses to urea solution concentration and amounts to be applied in order to improve digestibility of organic matter (OMD) and maintain alkaline pH to enable preservation of treated straw. The present experiment aimed at providing such information as part of a study to assess the potential of animal or human urines for upgrading straw and bearing in mind that urines contain a range of urea concentrations.