Micronutrientes na soja: produtividade a analise economicaMicronutrients in soybean: productivity and economic analysis

摘要

The availability of commercial products containing micronutrients has increased in the latest years, but experimental results have shown great variability, turning this matter into something contradictory. The reduction in relative cost in the use o micronutrients and the expectancy of scale gain, in the latest years, have motivated producers to use micronutrients such as: cobalt, boron and molybdenum because of their influence in the symbiotic fixing of nitrogen in soybean. This work aimed at determining the technical and economic viability of the application of some micronutrients, emphasizing AM and Co, in soybean productiveness. The experiment was carried out in the agricultural years of 2001/02 and 2002/03, at Paineira Farm, from SLC Agricola Ltda, in Coronel Bicaco, RS, in a Hapludox and it had been under no tillage for eight years. The experimental outlining was of random blacks with three repetitions, with portions of 10 x 15m. Soybean implantation was on 11/18/2001 and on 11/24/2002, with 225 and 190 thousand plants ha(-1), for the two agricultural years respectively. The spacing between lines was of 0,40m and the variety was RS-10 for the two years. Treatments in 2001/02 were: (1) CoMo; (2) CoMo + Mo; (3) CoMo + Mo + Mo: (4) CoMo + Mo + P30: (5) CoMo + B; (6) B; (7) Mo: (8) Mo + Mo; and (9) Testemunha. In 2002/03 treatments were: (1) CoMo + 2x Ho; (2) CoMo + 2x Mo + B,(3) CoMo + 2x Mo + Phitosol PK; (4) Canto + 2x Fortifol CaB; (5) CoMo + 2x Mo + LBE-PT1; (6) CoMo + 2x Mo + P30; (7) CoMo + 2x Mo + Stimulate; and (8) Testemunha. The use of micronutrients, especially Mo arid Co, has shown to be a contradictory one in the physical productiveness evaluation of the grains through the comparison of averages. However, in most cases, the economic return of the micronutrient application was positive, but it showed its dependence on high productiveness and favorable prices at the moment of commercialization.