Absorption of nutrientes by two cultivars of sunflower plants (Heliantus annuus L.) under field conditions: II. Micronutrients concentration

Abstract

In order to find out the absorption of the micronutrients during the growth of sunflower plants, a field experiment was carried out at the Centro Nacional de Pesquisa de Soja/EMBRAPA, Londrina, PR, Brazil. The soil used is classified as Latossolo Roxo (Eutrustox). The following doses of fertilizers were use: 0-0-0; 1-1-1; 2-1-1: 2-2-1; 2-0-0 (NPK). The population of plants were calculated in 62,500 per hectare, with a spacing of 0.80 m between the lines. The authors concluded: The lowest concentration of the nutrients occured near the period of maximum dry matter production (88 days) . For leaves diagnosis the following levels may be use - Cu = 27 ppm; Mn = 200 ppm; Zn = 31 ppm; B = 125 ppm and Fe = 227 ppm.