Development of Coffee Plants in Soils with Picloram Residues

This work aimed to evaluate the growth of coffee plants cultivated in an Oxisol with different pH values and contaminated with picloram residues. The experiment was a factorial (2 x 9), with the first factor consisting of two types of soil (Oxisol pH 4.4 and pH 6.2) and the second factor, nine doses of picloram (0, 20, 40, 60, 80, 100, 120, 140 and 160 g ha(-1)), arranged in a randomized block design with four replications. At 60 and 120 days after herbicide application (DAP), a visual evaluation was carried out of intoxication of the plants, leaf area, by a non-destructive method; stem diameter by caliper and plant height, as well as counting the number of fully-expanded leaves. At 120 DAP, determination of dry mass of the leaves, stem and roots was carried out, besides root length and root volume. It was concluded that coffee plants recently transplanted into soil with residues of picloram have a growth reduction that may affect future crop productivity. Operations aiming at increasing the pH of these soils increase the risk of carryover.