Fertilization response and potassium availability for soybean in oxisol

• Autor(a) principal: Borkert, Clóvis Manuel
• Data de Publicação: 1997
• Outros Autores: Sfredo, Gedi Jorge, Farias, José Renato Bouças, Tutida, Fábio, Spoladori, Cláudio Luis
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Pesquisa Agropecuária Brasileira (Online)
• Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/4749
• topic: Glycine max; residual effect; broadcast fertilization; adubação potássica; Glycine max; efeito residual

The soil, when intensively cultivated with soybean-wheat double-cropping system during several growing seasons, has the available K (fixed and specifically adsorbed K) reserves depleted after some years of cropping. This causes soil K deficiency for crops and yield reduction. The objective of this work was to study the soybean response to K fertilization, and the residual effect on soybean yields, on leaf and soil K content. The experiment was run with soybean during the growing seasons 1983/84 through 1992/93 in a 'Latossolo Roxo eutrófico' (Eutrorthox) in Londrina, Paraná State, Brazil. In the first five years rates of zero, 40, 80, 120, 160 and 200 kg/ha/year of K2O were applied. After ten years of experimentation it was concluded that in the 'Latossolos Roxos eutróficos' of high fertility, even with high K availability the soybean cannot be cultivated for more than two years without K fertilization, with high probability to have limitations to obtain maximum yields. The K maintenance of 80 kg/ha/year of K2O is not enough and in five years of double-cropping almost depleted the soil-K. The fertilization should be at least 120 kg/ha of K2O for soybean and 160 kg/ha/year of K2O for the soybean-wheat double-cropping system to keep top yields of 3,000 to 3,500 kg/ha. Soybean high yields, over 3,000 kg/ha, were associated with K in the leaf tissue higher than 17.1 g/kg.