Studies of the effects of manuring and season on the yield and chemical composition of the cattle cabbage

1. Ten manurial treatments were applied annually to cattle cabbage grown in a six-course rotation for 7 years. Samples were taken in the early winter each year, and from five harvests taken at fortnightly intervals in the last year. 2. The dry-matter yields each year closely followed the weather conditions during the growing season. There was no significant fall in the dry-matter yield during the last season. The treatments supplying phosphorus or phosphorus and potassium substantially increased yield, but the application of nitrogen did not. 3. The application of nitrogen, potassium or phosphorus increased the levels of these constituents in the crop in practically all cases. The application of phosphorus produced hearted plants which contained significantly less dry matter than the openleavod plants produced in its absence. The levels of ether extract, crude fibre, ash, silica and magnesium wore not significantly affected by the manorial treatments. 4. There was little variation in composition as the season advanced except for significant increases in the crude-fibre levels and decreases in the nitrogen-free extractives levels. 5. The distribution of the chemical components was investigated in the outer leaves, heart leaves and stem of the plant. This was compared with that in the marrow-stem kales. 6. The chemical composition of the cattle cabbage compares fairly closely with that found for the marrow-stem kales grown under similar conditions. It is, however, lower in dry matter, crude fibre, magnesium and chlorine. It may be considered as a replacement for marrow-stem kale as a source of crude protein and all the major minerals except chlorine and possibly magnesium.