IMPACT OF SOME SELECTED AGRICULTURAL MEASURES AND SITE CONDITIONS ON ECONOMICALLY SIGNIFICANT CHARACTERISTICS OF CRAMBE

In the years 1994–1999 and 2002–2008 the field trials with crambe (Crambe abyssinica Hochst. ex R.E. Fries) were conducted at four and two different sites, respectively. The sowing rates were 80 and 140 germinable seeds per square metre and three graded doses of N fertilization (0, 40, 80 kg.ha^–1) were applied in these trials. The yields of seed and straw, yield structure, health state and degree of stand infestation by pests were examined. Oil content in seeds and composition of individual fatty acids were determined every year. The length of growing season fluctuated between 110 and 130 days. Colder and damper conditions caused a prolongation and dryer conditions a shortening of vegetation period. The strongest occurrence of pests (flea beetles, blossom beetles) was found at the warmest site at Troubsko. The average seed yields varied between 0.84 t.ha^–1 and 2.47 t.ha^–1. Statistical evaluation showed that seed yields were significantly influenced by the site, year, N fertilization and sowing rates. Average oil content in crambe seeds (pods and pericarp) was 32.05% vol. From individual fatty acids, the erucic acid had the highest content (56.4%) followed by oleic acid (17.6%) and linoleic acid (10.9%). The used nitrogen rates had not any significant effect on oil content. The nitrogen rate 80 kg.ha^–1 reduced oil content in crambe seeds on average by 1.8% in comparison with non-fertilized plots