Produção de matéria seca e de grãos por plantas de feijoeiro (Phaseolus vulgaris L.) cultivadas em solos tratados com metais pesados

Abstract

The contamination of soil through heavy metals has become a stable preoccupation in last decades. Several studies have been accomplished upon the effects of these metals in plants an methods of relieving. This study in greenhouse had as goal to evaluate the contents of Cd, Pb, Zn and Cu solvable in DTPA (diethyleneaminopentacetic acid) extractor solution and to relate them to the production of dry material and grains through bean plants in two types of contaminated soils. Samples of distrofic-Red Latossol and humic-Yellow-Red Latossol contaminated with Cd, Pb, Cu and Zn were used. Four doses (mg dm-3) increasing and individual were applied to each metal: 0, 5, 10 and 20 to Cd; 0, 125, 250 and 500 to Pb; 0, 1,5, 4,5 and 13,5 to Cu and 0, 6, 18 and 54 to Zn with four repetitions with amount of 128 experimental units. The samples were collected, prepared and incubated in polietileno bags for total period of 60 days, of wich 30 days only with the doses of metals and maintaining humidity equivalent to 60% of total volume of pores and for more 30 days after doing the basic fertilization. After concluding the basic fertilization contents of heavy metals were evaluated through simple extraction using the DTPA method and 5 plants of bean were cultivated for experimental unit of wich after germination the cut maintaining only 3 plants to the end of the cicle when the production of dry material and grains was evaluated. There was decrease in the production of dry material in all treatments with exception in dose 0, and the production of grains was only drastically affected in treatments containing Cd, and Cu, Pb, and Zn short affected the production of grains.