Estudo dos efeitos de feijão vulgar, milho e tomate na fitorremediação de um solo contaminado por sulfatos

Abstract

Sulfur is one of the plant nutrients that has been receiving little attention in soil fertility studies, being relegated to little research in the world. It is a natural constituent of all fossil fuels and during combustion most of it is converted into gaseous sulfur compounds. It is oxidized in the atmosphere and after deposition in the soil, it originates the sulfate ion, which can be used by plants. Sulfate ion is the form of sulfur absorbed by plant roots and can also be used by soil organisms. The trial was set up in the greenhouse (nursery) belonging to the Department of Biological Sciences from April to July 2004. For the present work, three crops were used, namely common bean (Phaseolus vulgaris), maize (Zea mays) and tomato ( Lycopersicum esculentum) in a treatment of four different doses (0.15, 30 and 45mg/l) of sulfur in the form of potassium sulphate. Plants were harvested in the 4th, 8th and 12th week after sowing and were separated into leaf, stem and root to be subsequently dried for 48 hours in an oven at 80°C. After drying, the plant material was ground, mineralized by nitric-perchloric digestion and the sulfur content of the obtained extract was determined. The sulfur introduced into the soil must have been absorbed by the roots as it was found in the plant's stems and leaves. Its presence did not affect the normal development of crops, the beginning of flowering or the formation of fruits in common beans. The different concentrations of sulfur introduced into the soil did not affect the production of plant dry matter. In general there were no statistically significant differences between the treatments carried out and the control. Some significant differences were noted in the final distribution of dry matter accumulated in different parts of the plants. The corn plant was the one that accumulated more dry matter, reaching the highest values ​​in the leaves, followed by the stems and finally the roots. The correlation between total sulfur content and total weight in common bean and tomato crops was relatively negative. strong and strong respectively and positive and moderate correlation for the corn crop