%0 Journal Article
%T Agronomic efficiency of potassium fertilization in lettuce fertilized with alternative nutrient sources Efici¨ºncia agron mica da aduba  o pot¨¢ssica na alface adubada com fontes alternativas de nutrientes
%A Douglas Ramos Guelfi-Silva
%A Giuliano Marchi
%A Carlos Roberto Spehar
%A Luiz Roberto Guimar£¿es Guilherme
%J Revista Ci¨ºncia Agron£¿mica
%D 2013
%I Universidade Federal do Cear¨¢
%X The aim of this study was to evaluate the effect of alternative sources of nutrients on the nutrition, yield and efficiency of potassium fertilization in lettuce. The experiment was carried out in a greenhouse, using 3.7 kg pots filled with a dystrophic red-yellow Latosol of medium texture. The experimental design was randomized, with treatments divided into a 4 x 6 factorial: four doses of potassium (0; 200; 400; 600 kg ha-1 K2O) and six alternative sources of nutrients (breccia, ultramafic, biotite schist, phlogopite, and mining and Chapada by-products), with four replications. Content and accumulation were determined for potassium (K), copper (Cu), zinc (Zn) and nickel (Ni) in the lettuce shoots, and from these data two indices were calculated for the efficiency of potassium as a fertilizer. The application of increasing values of alternative sources of nutrients promoted improvements in nutrition and increases in lettuce yield. The efficiency of potassium fertilization decreased with the increase in values of potassium taken from alternative nutrient sources, with the mining by-products and the ultramafic being superior to the other sources. Crushed silicate rocks and mining by-products can therefore both be used as fertilizer in organic and conventional production systems. O objetivo desse estudo foi avaliar o efeito da aplica  o de fontes alternativas de nutrientes na nutri  o, produ  o e efici¨ºncia da aduba  o pot¨¢ssica na alface. O experimento foi conduzido em casa de vegeta  o, em vasos com 3,7 kg preenchidos com um Latossolo Vermelho Amarelo distr¨®fico de textura m¨¦dia. O delineamento experimental foi inteiramente casualizado e os tratamentos foram distribu¨ªdos em arranjo fatorial 4 x 6, sendo quatro doses de pot¨¢ssio (0; 200; 400; 600 kg ha-1 de K2O) e seis fontes alternativas de nutrientes (brecha, ultram¨¢fica, biotita xisto, flogopitito, subproduto de minera  o e subproduto de chapada), com quatro repeti  es. Foram determinados o teor e o ac¨²mulo de pot¨¢ssio (K), cobre (Cu), zinco (Zn) e n¨ªquel (Ni) na parte a¨¦rea da alface e com esses dados foram calculados dois ¨ªndices de efici¨ºncia da aduba  o pot¨¢ssica. As aplica  es de doses crescentes das fontes alternativas de nutrientes promoveram melhorias na nutri  o e aumentos na produ  o da alface. A efici¨ºncia da aduba  o pot¨¢ssica diminuiu com o aumento nas doses de pot¨¢ssio aplicadas pelas fontes alternativas de nutrientes, sendo que o subproduto de minera  o e a ultram¨¢fica foram superiores ¨¤s demais fontes. Diante disso, pode-se afirmar que as rochas silic¨¢ticas mo¨ªdas e os subprodutos de m
%K Lactuca sativa L
%K Rochas silic¨¢ticas
%K Subproduto de minera  o
%K Lactuca sativa L
%K Silicate rocks
%K Mining by-products
%U http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902013000200008