Publication Date
1993
Description
Cutting trials were conducted with lucerne (Medicago sativa) cv. S A Standard under dryland conditions over a period of 8 (1982 to 1989) years at 2 sites, one each in the western (Elsenburg) and southern (Tygerhoek) Cape. The sites differed in soil type and rainfall distribution. Replicated plots were harvested at 3 set frequencies (4·, 6- and 8- weekly). Production was lowest during summer and highest in late spring and increased with decreased harvesting frequency at both sites. These data were used to derive equations for the extrapolation of the seasonal yield. Inputs into the model 11cc average monthly climatic data (tempemture, solar radiation, pan evaporation and minfall). The model is based on the growth index (0sGISI) concept, GI being defined as the ratio between the actual and the potential rate of DM production. GI is calculated as the product of a soil moisture index (0SMISI), a radiation index (0SRISl) a'nd RTI (0SRTISI), with RTI the ratio between RI and a temperature index, Tl (OSTISl). The potential production of lucerne (kg OM/ha/day), calculated as 55.25•GJ+0.68, was significantly correlated with the actual production.
Citation
Van Heerden, J M., "Production of Dryland lucerne in the Western and Southern Cape Regions of South Africa" (2024). IGC Proceedings (1993-2023). 12.
https://uknowledge.uky.edu/igc/1993/session19/12
Included in
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Production of Dryland lucerne in the Western and Southern Cape Regions of South Africa
Cutting trials were conducted with lucerne (Medicago sativa) cv. S A Standard under dryland conditions over a period of 8 (1982 to 1989) years at 2 sites, one each in the western (Elsenburg) and southern (Tygerhoek) Cape. The sites differed in soil type and rainfall distribution. Replicated plots were harvested at 3 set frequencies (4·, 6- and 8- weekly). Production was lowest during summer and highest in late spring and increased with decreased harvesting frequency at both sites. These data were used to derive equations for the extrapolation of the seasonal yield. Inputs into the model 11cc average monthly climatic data (tempemture, solar radiation, pan evaporation and minfall). The model is based on the growth index (0sGISI) concept, GI being defined as the ratio between the actual and the potential rate of DM production. GI is calculated as the product of a soil moisture index (0SMISI), a radiation index (0SRISl) a'nd RTI (0SRTISI), with RTI the ratio between RI and a temperature index, Tl (OSTISl). The potential production of lucerne (kg OM/ha/day), calculated as 55.25•GJ+0.68, was significantly correlated with the actual production.
