ABSTRACT The use of organic waste in agriculture has stimulated the search for technologies that reduce environmental pollution. Among the residues are the biochar and swine wastewater (SW), which incorrectly disposed cause negative impacts, however, when combined, they can enhance agricultural production, due to the synergism between both. In this sense, the objective was to evaluate the influence of doses of biochar, from conilon coffee straw, combined or not with swine wastewater diluted to 50% (SW50%), on the nutrient content in medium and clayey texture soils and in the corn plant tissue. The experiment was carried out in a greenhouse, with five doses of biochar, two irrigation waters and two soils, with three repetitions. The pH, P, K+, Ca+2, Mg+2, Zn+2 and Na+ in the soil and N, P, K, Ca, Mg, Zn and Na in plant were evaluated. The addition of biochar in doses linearly increased the levels of P and K+ in both soil textures, with synergy when irrigated with SW50%. The SW50% provided a nutrients increase in the corn plant tissue. The agricultural use of biochar from conilon coffee straw was important to increase the content of P and, mainly, K in the aerial part of corn.

ABSTRACT The use of organic waste in agriculture has stimulated the search for technologies that reduce environmental pollution. Among the residues are the biochar and swine wastewater (SW), which incorrectly disposed cause negative impacts, however, when combined, they can enhance agricultural production, due to the synergism between both. In this sense, the objective was to evaluate the influence of doses of biochar, from conilon coffee straw, combined or not with swine wastewater diluted to 50% (SW50%), on the nutrient content in medium and clayey texture soils and in the corn plant tissue. The experiment was carried out in a greenhouse, with five doses of biochar, two irrigation waters and two soils, with three repetitions. The pH, P, K+, Ca+2, Mg+2, Zn+2 and Na+ in the soil and N, P, K, Ca, Mg, Zn and Na in plant were evaluated. The addition of biochar in doses linearly increased the levels of P and K+ in both soil textures, with synergy when irrigated with SW50%. The SW50% provided a nutrients increase in the corn plant tissue. The agricultural use of biochar from conilon coffee straw was important to increase the content of P and, mainly, K in the aerial part of corn.

Realizou-se este estudo com o objetivo de avaliar o efeito das aplicações sucessivas, em doses crescentes, de duas fontes de lodo de esgoto sobre os teores totais de Cu, Mn, Ni, Pb e Zn em solo, em três cultivos sucessivos de milho. O experimento foi conduzido no campo experimental da Embrapa Meio Ambiente, localizado em Jaguariúna-SP, durante os anos agrícolas 1999/2000 e 2000/2001, em Latossolo Vermelho Distroférrico. Os lodos utilizados no experimento foram obtidos nas Estações de Tratamento de Esgoto (ETEs) de Franca e Barueri. Os tratamentos, para cada fonte de lodo de esgoto, foram os seguintes: testemunha, sem adição de lodo de esgoto; NPK; aplicação de lodo de esgoto visando a suprir a quantidade de N normalmente requerida pelo milho; 2; 4 e 8 vezes a dose de lodo aplicada no tratamento 1N. As doses de lodo aplicadas (base seca) variaram de 0 a 139,24 Mg ha-1 para o lodo de Barueri e de 0 a 80,27 Mg ha-1 para o lodo de Franca. Avaliou-se o acúmulo de Cu, Mn, Ni, Pb e Zn pela determinação do teor total (água régia) desses metais no solo. Os teores totais de Cu e Zn em solo aumentaram com o acréscimo nas doses aplicadas das duas fontes de lodo; contudo, não foram verificados no solo teores totais dos metais pesados analisados acima dos valores estabelecidos em literatura para solos agrícolas.

This study was designed to evaluate the effect of the successive applications i crescent doses, of two sources of sewage sludge on the total contents of Cu, Mn, Ni, Pb and Zn in soil, in three successive crops of corn. The experiment was conducted in the experimental field of Embrapa Environment, located in Jaguariúna in São Paulo state over the agricultural years of 1999/2000 and 2000/2001 in a Diostroferic Red Latosol. The sludges utilized in the experiment were obtained in the Sewage Treatment Stations (STSs) of Franca and Barueri. The treatments for each source of sewage sludge were the following: control, without addition of sewage sludge; NPK; application of sewage sludge aiming to supply the amount of N normally required by corn; 2, 4 and 8 times the rate of sludge applied in the 1N treatment. The rates of sludge applied (dry basis) ranged from 0 to 139.24 Mg ha-1 for Barueri sludge and from 0 to 80.27 Mg ha-1 for Franca sludge. The accumulation of Cu, Mn, Ni, Pb and Zn through the determination of the total content (regia water) of these metals in soil were evaluated. The total contents of soil Cu and Zn increased with the increment of applied doses of the two sludge sources, however, were not verified in soils, total contents of the heavy metals analyzed above the values established in literature for agricultural soils.