Vermicompostagem de lodo de curtume na cultura do tomateiro irrigado com água residuária de esgoto doméstico

Abstract

This study developed different experiments in greenhouse conditions, which, in general, sought to evaluate the use of vermicompost of tannery sludge and domestic sewage in tomato (Solanum lycopersicum L.). The first study evaluated the vermicomposting tannery sludge mixed with cattle manure, poultry litter, sugarcane and rice husk ash in different proportions, in order to produce vermicompost with high nutritional quality, such as waste treatment technology. The results showed that the vermicompost produced with Eisenia foetida present in most parameters assessed in treatment, statistical differences on the treatments, and the comparison made between the initial and final values. The final concentrations of the variables N, P, K, Ca, Mg, and Ni were, in general, larger than the initial concentrations for all treatments, favoring a final destination environmentally suitable for tannery sludge, since the results allowed the use of these as fertilizer for later plant nutrition. In general, vermicomposts had C/N, chromium, nitrogen, pH, copper, nickel and lead appropriate technical specifications of Instruction MAPA and CONAMA resolution, highlighting the T1 (100% EB) and T8 (25% LC + 75% CC). The second study investigated the production of tomato (Solanum lycopersicum L.) variety Santa Cruz Kada (paulista) irrigated with domestic wastewater and fertilized with tannery sludge vermicompost in a typical Dystrophic Red Latosol (Oxisol). From the first study was chosen the best vermicompost seeking fertility and a source of potassium as a criterion of choice. For the results obtained T2 (25% Sludge tannery + rice husk) had a higher weight value of the fruits as well as production (6.68 kg) and longitudinal diameter. For pH values of tomato fruits stands T4 (50% Sludge tannery + Grey cane) value of 4.40, which does not differ from other treatments, except for T1 (25% Sludge tannery + manure beef). For different types of water (wastewater and water supply) it is observed that the T3 (50% Sludge tannery + bovine manure) and T5 (conventional fertilization) have higher values of pH and Brix. For the time it was observed that there was no interaction between the sources of variation "treatments" and "water". According to nutritional assessment, only boron showed values below critical levels, which does not hurt production. The thirtd study aimed to evaluate the effect of tannery sludge vermicompost in chemical properties of soil cultivated with tomato and irrigated with wastewater. As shown in the results the addition of vermicomposto, mainly in the addition of T2 = 25% + LC 75% of rice husk and T4 = 50% + LC 50% cane ash, increasing concentrations of soil chemical properties, favoring this condition as soil conditioner even after the tomato crop. Thus, it is concluded that the tannery sludge vermicompost mixed with different substrates are important sources of nutrients for the tomato crop favored by irrigation domestic sewage. However, we suggest caution in the use of these residues in agricultural reuse for environmental preservation, since there may be excess nutrients when applying vermicompost combined with the domestic sewage, the latter should be used to complement the made fertilization. The increase of nutrients in the soil, since significant increases were observed in all the elements, demonstrating viability as biotechnology disposal of waste must be observed.