Chemical quality of the burnt and non‐burnt grass layer in the Nylsvlei Nature Reserve, South Africa
1999
DÖrgeloh, Werner G.
The forage quality of the herbaceous layer in burnt and non‐burnt plant communities was determined seasonally to serve as a baseline for managing the food supply. The near‐infrared reflectance spectroscopy method and wet chemical analyses were applied to analyse the grass samples. Differences in forage quality were found between plant communities. The Sporobolus ioclados–Acacia tortilis Savanna had the highest forage quality throughout the year. Plant communities on the lithosols had a low forage quality. The highest total calcium and total phosphorus concentrations were found in the Eragrostis pallens–Burkea africana Savanna, total potassium in the plant communities on the lithosols, and total sodium in the Sporobolus ioclados–Acacia tortilis Savanna and floodplain. The most optimum Ca:P ratio was found in the Eragrostis pallens–Burkea africana Savanna when burnt and non‐burnt. In non‐burnt areas the highest K:Na ratio was found in the Sporobolus ioclados–Acacia tortilis Savanna. Burning increased the forage quality in some plant communities. In general, only percentage in vitro organic matter digestibility differed significantly between burnt and non‐burnt plant communities. The forage quality did not increase significantly in plant communities on lithosols and on vertisols. Mineral ratios did not differ between newly burnt plant communities. A low protein and mineral content in the winter forage should be countered with supplementary feeding or burning of grass to improve the condition of animals.
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