Accumulation of heavy metals and chemical alterations in a Ultisol cultivated with melon

Soil cultivation using agrochemicals may increase the concentration of availability of heavy metals to plant and cause contamination of the trophic chain as well. This work was carried out to evaluate the influence of length of time under cultivation with melon (Cucumis melo L.) on the heavy metals accumulation and chemical alterations in Ultisol. Melon plantations of one, two and three years were studied. A benchmark area under natural vegetation was used to compare the data obtained. The results showed that the lengthiest time under cultivation altered the chemical characteristics of the soil. An increase in pH and contents of N, P and K was observed for the two soil layers evaluated. On the other hand, Ca contents were decreased by cultivation. The larger the cultivation time the higher the concentration of N, Pb, Cu, and Mn in the soil surface layer, whereas the Fe and Zn concentrations were diminished in both analyzed soil layers, though available concentrations are still regarded as low in soil.