PHOSPHORUS AND ZINC FERTILIZATION EFFECTS ON DRY-MATTER YIELD AND PHOSPHORUS AND ZINC UPTAKE BY CRAMBE

Crambe (Crambe abyssinica Hochist.) is an oilseed crop high in euricic acid with industrial applications in production of nylon, plasticizers, and lubricants. Little information is available on crambe response to phosphorus (P) and zinc (Zn) fertilization. This glasshouse study was conducted to evaluate the response of crambe to four rates of P and five rates of Zn fertilizer application to a soil with 10 mg/kg NaHCO3-extractable P and 0.6 mg/kg DTPA-extractable Zn. Phosphorus fertilizer, but not Zn fertilizer, increased the dry matter yield of plant tops. Phosphorus response was consistent in both 35- and 62-day-old plants. Zinc response was most consistent in 35 day-old plants. Significant interactions were observed between P and Zn for dry matter weight, P:Zn ratio, and Zn uptake at 35 days. No significant interactions were observed at 62 days. Analysis of the data showed a negative correlation coefficient between P or Zn treatment and tissue concentration or uptake for the opposite element.