Effects of drought, nitrogen, spacing and defoliation on vegetative growth and development, yield and quality of kale (brassica oleracea var. acephala
Abstract
There is hardly any study reported in literature on the
cultural practices for vegetable kale production. Greenhouse
and field experiments were conducted to study the effects of
drought, three water regimes (irrigating when available soil
moisture had been depleted to 75, 50 or 25 percent), two
spacings (21,489 or 42,978 plants/ha), two rates (0 or 135
kg/ha) of N side-dressing, defoliation and supplementary irrigation
on growth, development, yield and quality of
vegetable ~ale plants.
During wilting of kale plants, young leaves retained
more water than the old leaves. The old leaves became
senescent and were shed.
Irrigating when the plants had depleted available soil
moisture to 75 percent did not significantly differ from irrigating
when soil moisture had been depleted to 50 percent.
However, allowing the plants to deplete the available soil
moisture to 25 percent significantly retarded their growth.
Drought at an early growth stage of the plants did not
significantly affect their growth and development. However,
drought at any stage of growth of the plants reduced yield.
Wide spacing increased fresh and dry weights, number of
leaves and branching per plant, whereas close spacing increased
total above ground, leaf and marketable yields.
Nitrogen side-dressing increased fresh and dry weights per
plant of widely spaced plants only.
Nitrogen side-dressing did not have significant effects
on quality of kale leaves. However, irrigating side-dressed
plants, and wide spacing, increased nitrate-N content in the
leaves. Close spacing increased dietary fiber ~nd thiocyanate
ion contents in the leaves.
Defoliation increased final cumulative number of leaves
and harvest index but decreased plant height, branching and
fresh and dry weights per plant, and unmarketable leaf yield
per hectare.
Defoliating widely spaced plants decreased the final
total cumulative yield per hectare.
Defoliation x nitrogen and spacirtgx supplementary irrigation
interaction was significant for leaf production on
the axillary branches, and total nitrogen content of the
leaves.
Main effects of nitrogen, spacing, supplementary irrigation
and defoliation on the contents of macro- and microelements,
in the plants, were not significc~t.
Citation
Chweya, J A(1982). Effects of drought, nitrogen, spacing and defoliation on vegetative growth and development, yield and quality of kale (brassica oleracea var. acephalaPublisher
College of Agriculture and Veterinary Sciences, University of Nairobi
Subject
DroughtNitrogen
Spacing
Defoliation
Vegetative growth
Development
yield
Quality
Kale
(Brassica oleracea var. acephala
Description
PhD Thesis