Elemental and Fibre Contents of Savanna Grasses: Variation with Grazing, Soil Type, Season and Species

• Published in: The Journal of applied ecology 1990-08, Vol.27 (2), p.623-634
• Main Authors: Georgiadis, Nicholas J., McNaughton, Samuel J.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Cell walls; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Generalities. Production, biomass, yield. Quality; Grasses; Grazing; Growing seasons; Herbivores; Livestock; Plants; Savanna soils; Savannas; Soil ecology
• ISSN: 0021-8901; 1365-2664
• DOI: 10.2307/2404307

(1) The contents of water, crude protein, cell contents, cell wall, lignocellulose, hemicellulose, cellulose, lignin, silica, ash and nineteen elements, and their variation with season, soil type and grazing intensity, were examined in East African savanna grasses. (2) As the growing season progressed, there was a systematic decline in nutritional value at all sites, as indicated by fibre properties. However, fibre nutritional values were at all times higher in areas of high herbivore use intensity (HUI) than of low HUI. There were few differences in fibre properties between soil types. (3) In contrast, there were marked differences in element contents between samples from different soil types, and relatively less variation in element contents with time and HUI. Much of the between-site variation was due to different plant species compositions. (4) These contrasting patterns of variation resulted in poor correlations between fibre properties and element contents. (5) The data suggest that grazing animals can regulate plant nutritional properties by increasing soil nutrient levels and by changing species composition. Their activities may contribute to the development of localized areas of nutritional sufficiency in the absence of intrinsic soil differences.