| dc.description.abstract | Two experiments one on plant population, the
of her on NPK fertilizers were carried out to determine
the influence of plant density and fertilizers on the
vegetative growth and propagation of pyrethrum. Clone
0/64/219 was usad for both experiments.
In the plant population experiment, five plant
densities - 18.0, 21.0, 25.5, 33.0 and 48.0 plants
per m were tested. Plant competition was found to
affect the tillering potential of the young pyrethrum
plant. It was. however, tiller production per plant,
rather than tiller prod0ction on unit area basis that
was significantly affected by competition. It was
suggested that high plant densities were able to
compensate for the low tillering capacity of individual
plants by the great number of plants per unit area.
The vigour of tillers produced - with regards to dry
matter production and root length - was also
influenced by the plant density. In terms of tota
tiller production and the vigour of the tillers, the
plant density of 25.5 plants per m2 obtained at a
spacing of 25cm between rows and 20cm within row
gave th8 best results. Management of plots under
dense populations also posed a problem, especially
in planting and weed control.
Three types of fertilizers - Calcium ammonium
nitrate, Double superphosphate and Sulphate of potash,
each at three rates were tested. The rates were 0,65 and
130 Kg Nlha for the nitrogen fertilizer, 0,29.7 and 59.3
Kg Plha for the phosphate fertilizer and 0, 8.3.and
16.6 Kg Klha for the potash fertilizer. Only nitrogen
application promoted tiller production, with best
results in the absence of both phosphorus and
potassium. Both nitrogen and phosphorus increased dry
matter production, but not in the presence of high
levels of potash. There was notable negative
interaction between nitrogen and phosphorus, with
regards to dry matter production. The effect of
nitrogen on root length was doubtful, mor,e so in the
presence of either phosphorus or potassium or both.
Phosphorus and potassium encouraged root elongation,
but their interaction was generally negative. It
was therefore concluded that an early application
of phosphate appears necessary for the initial root
and shoot developw,3nt, but not after the onset of
tillering when nitrogen should be more beneficial. | en |
