See more from this Session: General Global Agronomy: I
Monday, October 17, 2011
Henry Gonzalez Convention Center, Hall C, Street Level
The need of learning about the effects of applying agroindustrial (metallurgical residue and lime mud) and urban residues (biosolid) in the soil-plant system, has stimulated the search for experimental field results in long-term studies. Treatments were constituted of four residues and four levels, including two types of biosolids, a centrifuged and alkaline one (pH 12.0) treated with CaO (LC) and a biodigested and more acid one (LB; pH 7.0), in addition to steel slag (LS) and lime mud (LL) from paper and cellulose industry. The levels of such residues corresponded to 0, 2, 4 and 8 Mg ha-1, dry basis, besides a control. Since the beginning of the studies (2002 year), residues were applied on surface at four times without incorporation during soybean cultivation. This study was conducted in an Haplodux soil, at Lageado Experimental Farm, São Paulo State University, Botucatu, Brazil. After tree application (2008 year), the Mn and Zn contents in soybean leaves increased and they were above the adequate contents considering all residues. In this year, the contents of Mn and Zn in leaves were maximal, respectively 438 mg kg-1 and 274 mg kg-1 for 8.0 Mg ha-1 LB. In 2010 year, after four applications, the leaves kept a higher content of Mn (219.8 mg kg-1) and Zn (189.8 mg kg-1) only for 8.0 Mg ha-1 of LB, both above the adequate contents. The Cu and Fe content in leaves kept within the adequate levels, on average 12.8 and 91.5 mg kg-1, respectively. After four application of residues, the grains has a adequate content of Cu, Fe and Mn. Zn was above the adequate content and it was 80 mg kg-1 for 8.0 Mg ha-1 of LB, that resulted in a decrease of soybean yield, when compared to LC, LS and LL applications.