| dc.description.abstract | Two experiments were conducted between August,
1988 and March, 1989 at the Field station of the Fac~lty
of Agricul t ur e , Kabete Campus, Uni versi ty of Nairobi, to
study the effect of " .. nl.,-rogen (N) rates on growth, leaf
yield and nutritive quality of black nightshade (Solanum
nigrum L.). Four N rates (0, 5, 1~ and 15 9 per plant) in
the form of Calcium Ammonium Nitrate (26%N) were used. The
plant growth was assessed by the determination of plant
number of leaves and bran-ches per plant, while fresh weight of edibl e portions in tons per hectare was
used to assess the plant yield. The plant height, number
of leaves and branches per plant increased significantly
(p = 0.05 ) with increasing rates of N fertilizer.
However, plants top-dressed with N higher than 5g per
p Iant did not show significant increase in growth.
Nitrogen rates had significant effect on fresh weight
with plants that were top-dressed with 5g of N per plant
giving the highest yield of 44.5 tons per hectare.
The 1eaves were anal y sed for proximate chemi cal
cornposition, B-carotene, ascorbic acid and six minerals
including calcium and iron. B-carotene, total ash, crud e
fat, crude protein, potassium, calcium and ma cn es i urn
levels increased with increasing rates of ~~ application.
(xiii)
However ~he levels of ascorbic acid and crude fibre were
significantly decreased by higher N rates. Sodium, iron and
zinc contents in leaves tended not to be influenced by Nrates.
The evaluation of anti-nutrient factors in leaves
involved the determination of nitrate-Nitrogen (N03-N),
oxalates and total phenolics. Nitrate-nitrogen in the
leaves increased significantly with increasing rates of N
application while the oxalate content in leaves tended to
decrease with increasing N rates. Nitrogen rates had no
significant effect on the total phenolic content in
the leaves. | en |
