Studies of the chemical composition of kales and rapes. II. The rapes

Abstract

1. Three varieties of giant rape, two broad leaved Essex rapes, Hungry Gap Kale and Rape-Kale, were grown at two centres in mid-Wales. They were sampled in the early winter period and the samples divided into separate leaf and stem samples. These samples were used to calculate leaf to stem ratios on a green and dry-matter basis.2. The levels of the proximate constituents, silica, calcium, magnesium, phosphorus, sodium, potassium, chlorine, total sulphur, sulphate sulphur and ‘organic’ sulphur were determined in the dried samples. Whole plant values were calculated from the leaf and stem values with the appropriate leaf to stem ratios.3. The leaf values for ether extract, crude protein, silica-free ash, silica, calcium, phosphorus, magnesium, chlorine, total sulphur and ‘organic’ sulphur are higher than the corresponding stem values. For dry matter, crude fibre, nitrogen-free extractives and sodium the reverse is found, whilst for sulphate sulphur there is no definite distribution.4. There are no significant differences in composition between the main groups of varieties, and the rape-type kales are very similar to the other rapes in this respect.