The utilization of Hyparrhenia veld for the nutrition of cattle in the dry season I. The effects of nitrogen fertilizers and mowing régimes on herbage yields

Abstract

1. The potential herbage yield of Hyparrhenia veld under mowing and fertilizer managements was measured, as a part of the work to study the utilization of the natural grassland for the feeding of cattle in the dry season.2. The uninterrupted seasonal pattern of herbage growth results in a relatively large yield of stemmy, low-quality fodder at the end of the growing season.3. Cutting at simulated ‘silage’ and ‘hay’ stages of growth reduced herbage yields compared with one, end-of-season harvest, but because of increased leanness, the regrowth herbage had a higher crude-protein content.4. The seasonal crude-protein yield was unaffected by mowing treatments, and a reduction in herbage yield was counterbalanced by an increase in percentage crude protein.5. The use of nitrogenous fertilizers resulted in a large increase in both herbage yield and percentage crude protein. The calculated nitrogen recovery was approximately 40%.6. There were no harmful effects on either veld vigour or botanical composition after 4 years of mowing and fertilizer treatments. The nitrogen fertilizer treatments alone showed a transient residual effect.7. The practical bearing of the results is discussed briefly. Only a low-quality fodder can, in practice, be harvested from the natural grassland, unless nitrogen fertilizers are used.