Soil biochemical activities and the geometric mean of enzyme activities after application of sewage sludge and sewage sludge biochar to soil

Abstract

There is a need to improve the way in which wastes, such as sewage sludges, are managed and a potential way to proceed would be to transform them into biochar. On the other hand, there is a growing interest in the use of soil biochemical properties as indicators of soil quality because they are sensitive to alterations in soil management. Thus, we have studied the effect of a biochar obtained from sewage sludge on soil biochemical properties in an organic soil using two doses of biochar and comparing these results with the control soil and with soils amended with the same two doses of unpyrolyzed sewage sludge. Microbial biomass C, soil respiration, net N mineralization and several enzyme activities (dehydrogenase, β-glucosidase, phosphomoesterase and arylsulphatase) were monitored. The geometric mean of enzyme activities (GMea) was used as a soil quality index. Individual biochemical properties showed a different response to the treatments, while GMea showed an increase in the quality of soils amended with the high biochar dose and a decrease in those amended with a high sewage sludge dose. The geometric mean of enzyme activities was a suitable index to condense the whole set of soil enzyme values in a single numerical value, which was sensitive to management practices.

Factors driving the carbon mineralization priming effect in a sandy loam soil amended with different types of biochar

“…The initial organic matter mineralization was very similar in all cases (C parameter ranged from 6.07 to 7.91) according to Mén-dez et al (2012), who found an increment of CO 2 emissions after application at the same rate after application of biochar prepared from sludge to a similar sandy soil or results obtained by Smith (2010). Nevertheless, Paz-Ferreiro et al (2012) found a negative priming effect after sewage sludge biochar application (prepared at 650 • C) to an Umbrisol. Indeed, Zimmerman et al (2011) concluded that discrepancies in C mineralization of biochar-treated soils are likely due to the type of both soil and biochar, the duration of the experiment and the dose of used biochar.…”

Biochar Types from Latrine Waste and Sewage Sludge Differ in Physico-Chemical Properties and Cadmium Adsorption

“…Production of biochar from latrine waste and sewage sludge could have potential uses in heavy metal removal from wastewater. Pyrolysis of these fecal wastes to biochar could recover carbon and nutrients (Hossain et al, 2011;Paz-Ferreiro et al, 2012;Mendez et al, 2012).…”

Poultry Litter Biochar: An Approach towards Poultry Litter Management – A Review

“…Increased sorption capacity of the soil was reported by Paz-Ferreiro et al, (2012) after amendment with biochar and mineral components into the soil (Paz-Ferreiro et al, 2012). Ameloot et al, (2013b) showed that the type of biochar alone has a significant effect on soil enzymatic activity, they proved that poultry litter biochar produced at 400°C and amended to soil caused a significant increase in the activity of dehydrogenases enzyme, whereas the same biochar obtained at 500°C reduced the activity of these enzymes over two times compared to the control (Ameloot, 2013b.).…”