Laboratoriumondersoek na optimum behandelingskondisies vir enkelvoudige en kombinasiebehandeling van koringstrooi met ureum en b

Author: A.A. Brand, S.W.P. Cloete & J. Coetzee
Year: 1989
Issue: 2
Volume: 19
Page: 84 - 87

Laboratory investigation into optimal conditions for the treatment of wheat straw with urea and caustic soda, exclusively or in combination.


The effect of treating wheat straw with 55 g urea and 45 g caustic soda (exclusively and in combination) per kg straw was investigated in a 3x2x6 factorial experiment. The design also included moisture levels of 250 and 400 g kg-1 straw and treatment periods of 0, ½, 1, 2, 4, and 8 weeks. Values for total nitrogen, urea, cell wall constituents (CWC) and in vitro organic matter digestibility (IVOMD) were determined. The urea treatment resulted in a fast hydrolysis of urea during the first two weeks, after which the rate of hydrolysis gradually decreased. The combined treatment substantially reduced the rate of urea degradation, probably owing to the inclusion of caustic soda. The rate of urea hydrolysis in the urea and combined treatment was accelerated by the higher moisture level, resulting in a more efficient treatment. The IVOMD of the combined treatment increased sharply during the first week after treatment, whereas the IVOMD of urea ammoniated straw gradually increased over the entire treatment period. The IVOMD of the combined treatment was substantially higher than that of the urea and NaOH treatments. The IVOMD of the caustic soda treated straw peaked immediately after treatment, after which the IVOMD appeared to decline up to and including 8 weeks of treatment. Cell wall constituents of the treated straw decreased as the treatment period increased up to 8 weeks.








Keywords: caustic soda, in vitro digestibility, moisture level, N content, treatment period, Urea-ammoniation
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