Efeito da aplicação de percolado de resíduo sólido urbano em solo cultivado com capim-tifton 85 / Effect from the application of the municipal refuse percolate on the soil cropped with Tifton-85 grass

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The effects from the application of different percolate rates of municipal solid waste (RSU) on the chemical characteristics of the soil, productivity and mineral composition of the tifton- 85 grass (Cynodon spp) were evaluated. The experiment was conducted in the Experimental Area for Treatment of Residues pertaining to the Department of Agricultural Engineering - UFV, Viçosa - MG. For the development of this research, a reservoir with 5,000L capacity was infilled with new RSU in order to produce the percolate for application on the tifton -85 grass. The percolate was applied at rates 250, 500, 750, 1000 kg ha-1 d-1 DBO. The treatments were initiated on October 07, 2006 and finished on June 01, 2007. The grass was cut five times, whenever it reached 0.40m. Those cuts were performed at 30, 31, 36, 46 and 62 days from resprouting. In the chemical analyses of the soil, the following procedure were performed: measurements of pH and CE, quantification of either NO3- and concentrations of N, NH4+, available P, and exchangeable concentrations of K, Ca, Mg, Fe, Cu, Zn, Mn, Cd, Pb, Ni, Cr, besides determining by calculation the exchangeable SB, index of saturation by bases, sodium, potential acidity, exchangeable acidity, MO and CTC contents. The randomized block experimental design was used, with five treatments and four replicates. For statistical analysis of the soil characteristics, the experiment was set up with four treatments (application rate), five replicates in time (cuts) and five soil depths (0 to 0.10; 0.10 to 0.20; 0.20 to 0.30; 0.30 to 0.40; and 0.60 to 0.70m). The data were subjected to the regression analysis. In vegetal tissue of the grass, the concentrations of N, P, K, Na, Ca, Mg and the heavy metals Fe, Mn, Cu, Pb, Zn, Cd and Ni were quantified. The content of crude protein (PB) was obtained, by multiplying the nitrogen content by 6.25. For the statistical analysis of the concentration of nutrients in the plants, the split-plot design was used with five DBO concentrations in the plots and the cuts in the subplots, under a randomized block design with four replicates. The data were subjected to both regression and variance analyses. According to the results, the following conclusions were drawn: the application of the RSU percolate caused alteration in the values of N, Na, K, P, NO3 -, Mn, Fe, SB, CTC and V in the soil; there occurred the sodium accumulation in the soil at all layers under study; however, no damage occurred in the soil quality neither in the grass productivity during the experimental period; in most cuts, an increase occurred in the concentrations of N, K, Na, Ca, Mg, Mn, Cd, Pb and Fe with the application of the RSU percolate doses; concerning to heavy metals, the copper showed high concentrations in all RSU-percolate application rates, although the very close values shown by the control. In all cuts, positive effect of the RSU percolate doses occurred in P; although, in the case of the MS productivity, this effect occurred just in cuts 3, 4 and 5. The application rates below 750kg ha-1 day-1 DBO of the RSU percolate provided no problems to the development of the tifton-85 grass, during the period under study, therefore they can be used. However, the monitoring of the chemical characteristics of both soil and underground waters is advisable, when evaluating the risks of environmental contamination.

ASSUNTO(S)

forrage plants fertirrigation forrageira waste water Águas residuárias fertirrigação engenharia de agua e solo

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