EFFECT OF FERTILISER NITROGEN AND POTASSIUM UPON YIELD AND QUALITY OF CARNATIONS GROWN IN PEAT AND SAWDUST

The carnation cultivar Dark Lena was grown under plastic cover in sphagnum peat, pine sawdust and mixtures of these constituents. Two levels of nitrogen and potassium were applied. Three times during the growing season leaf samples were collected and the total as well as soluble form of N, P, K, and Ca was determined.

The number of flowers ranged form 207 to 216 per m² but differences between treatments were not significant. Plant grown in peat-sawdust mixtures in most cases had longer stems and greater inflorescence diameter than in peat or sawdust alone. Higher doses of nitrogen increased inflorescence diameter of plants grown in sawdust and in mixture of 25% peat and 75% sawdust. A higher dose of potassium increased stem length of plants grown in mixture of 50% peat and 50% sawdust.

The lowest content of total and soluble form of nitrogen was found in leaves of plants grown in sawdust. Differences in phosphorus content between treatments were not big. An increased dose of potassium only slightly increased the content of that element in leaves.

Calcium content increased in leaves with time. A double dose of potassium decreased the total and soluble forms of calcium in leaves at all terms of sampling. The soluble form of elements constituted: N 7.5% to 8.4%, P 76% to 89%, K above 95%, Ca 64% to 75%.