Possible Recycling of Brewery Waste in Maize Production

Abstract

In this study, brewery sludge was evaluated in comparison with the recommended NP mineral fertilizer rate to elucidate a potential source of nutrients for maize crop. Randomized complete block design (RCBD) was laid out in three blocks at the experimental site. Physicochemical properties of the experimental soil and brewery sludge (BS) were evaluated in the soil laboratory. The N content of the grain and straw samples were determined using the wet digestion method. Heavy metals (Fe, Cu, Zn, Mn, Cr, Mo, Co, Pb, Se, and Cd) were extracted by DTPA extraction method and measured by atomic absorption spectrophotometer. The application of a 15 t ha^-1 sludge rate showed the highest grain yield that exceeds the value recorded from NP-treated and control plots by 3.15 t ha^-1 and 4.42 t ha^-1, respectively. Similarly, the application of 12.5 t ha^-1 sludge rate significantly increased the total nitrogen uptake of the crop (grain and straw) by 146.13% and 223.16% over the NP and control plots, respectively. There was 93.23%, 57.14%, and 76.78% higher significant difference of total nitrogen, organic carbon, and available phosphorus (mg kg^-1) in BS than the composition found in experimental soil before the application of treatments, respectively. The application of sludge maintained most of the heavy metal concentrations to the level of safety for health following the recommended ranges by World Health Organizations (WHO). In conclusion, future long-term study is required to elucidate the effect of the sludge on soil biology, the chemical property of soil (pH and salinity), and pathogen contaminations on soil and crop production.