Nutrient content in rose leaves as affected by potassium applications through drip irrigation

In order to evaluate rose leaf nutrient content as affected by potassium (K) dosages applied through drip irrigation, 'Sonia' and 'Red Success' cut roses were grown under a plastic greenhouse in Vicosa, Brazil. A randomized complete block split plot factorial experiment with four replications was carried out. The four potassium (K) dosages (0, 30, 60 and go g m(-2) year(-1)) formed the main plots and the two rose cultivars the subplots. Foliar analysis was done in order to determine plant nutrient uptake curves during the plant growth and production cycles. In the absence of potassium (control), the leaf K contents decreased from 2.46 and 2.41 to 1.47 and 1.46 dag kg(-1) after 60 and 635 days for 'Red Success' and 'Sonia' plants, respectively. With K application, leaf K contents decreased from 2.41 and 2.34 to 1.80 and 1.54 dag kg(-1) after 60 and 635 days for 'Red Success' and 'Sonia', respectively, suggesting that the existing soil K was enough to provide satisfactory rose leaf K content, once the exhibited leaf K contents were in the optimal range for most commercial cut rose cultivars.