Micronutrientes no solo e no milho em plantio direto com aplicações de dejetos líquidos de bovinos

Abstract

The use of cattle slurry ( DLB ) as a source of nutrients on farms is a common practice . Studies are needed to assess the effect of DLB in the availability of micronutrients , considering that applications may cause excessive accumulation of Cu and Zn in the topsoil . The aim of this study was to determine how long you can implement DLB in agriculture considering the restrictions of adding micronutrients to the soil , imposed by existing laws , and to evaluate the influence of DLB in the levels of micronutrients in soil and plants corn under no-tillage system . The study was conducted in the city of Ponta Grossa, state of Parana , in a Red- Yellow francoargiloarenosa texture tillage system was more than 13 years. The DLB was applied for seven consecutive years , or 3.5 years at dosages of 0 , 60 , 120 and 180 m3 ha - 1 yr- 1 , half of the summer crop and winter crop in half . In the seventh season , maize was assessed and , after harvest , we assessed for soil to 100 cm depth . It was observed that the application of DLB increased Cu, Zn and Mn only the 0-10 cm layer of soil . The increased levels of micronutrients in the soil did not improve the yields and contents of nutrients in corn plants . Considering the current legislation , it is possible to implement DLB for 17 years under the conditions of the study , limitation imposed mainly by the levels of Zn in manure .