Profitability and efficiency of fertilization in a corn/ soybean/ corn system in a latosol with improved fertility

Abstract

Currently, there are some doubts regarding fertilization dimensioning that aims at a high grain yield in soils with improved fertility in a crop rotation system. Thus, the objective of this study was to evaluate the yield and profitability resulting from different combinations of NPK fertilization and the efficiency of these nutrients in sequential crops of corn/soybean/corn, in a Latosol with improved fertility, in a farm located in the region of Campo das Vertentes, Minas Gerais State, Brazil. Four doses of sowing fertilization and topdressing were compared, corresponding to approximate proportions of 25, 50, 100 and 150 % of the doses usually applied by farmers. Nutrients sources varied according to the inputs used in the farm for each crop. In a soil with improved fertility, corn is more responsive to fertilization than soybean, with higher grain yield gains associated with N and K supply, while P is less limiting. The most profitable nutrients combination for this system involves increasing the amounts of N and K and reducing the amount of P in relation to the standard fertilization employed on the farm, providing a 14.3 % higher profit and higher average nutrient use efficiency.