The K is often related to the hardening process, in order to adapt the seedling to the field planting conditions. Thus, the objective of this experiment was evaluate the effect of K on the quality of seedlings of three hybrids clones of Eucalyptus (E. grandis x E. urophylla). The experiment was carried out in the seedling nursery of the CENIBRA enterprise. The doses of K was: 0, 249, 747, 1494 and 2988 mg L-1. With 87 and 88 days, were avaluated: the shoot height, collar diameter increment, ratio shoot height / collar diameter, K concentration in leaves and N/K ratio in leaves. The K application in the hardening phase increased, up to a given dose, the collar diameter for the three clones evaluated, but the height was not influenced. The absence of K resulted in the greatest values of the ration height / collar diameter for the three clones evaluated, while on the seedlings that received K, the rate showed smaller and similar values. The application with increasing doses of K resulted in greater leaf concentrations of this nutrient. All the treatment showed values of N/K ratio within what is considered appropriate, except for the greatest level of K. It can be concluded that, during the hardening phase, the potassic fertilization is recommended, and being indicated the dose of 249 mg L-1 of K because provides the best values of collar diameter increment.
Eucalyptus; minicutting and hardening
