Influence of pig manure and its biochar on soil CO2 emissions and soil enzymes

Biochar production from manure wastes, including pig manure, could provide a valuable alternative to current waste management practices, while offering an opportunity to improve soil properties and to reduce the risk of contamination derived from the direct application of manure as a soil amendment. Two different biochar samples, produced from pig manure at 300 °C (BPC300) and 500 °C (BPC500) were used to evaluate the impact of biochar amendment on soil enzymatic activity and soil CO2 emissions. An incubation experiment was designed as follows: selected soil (S) was amended with pig manure (PC) and two pig manure biochars prepared at 300 °C (BPC300) and 500 °C (BPC500) at a rate of 8 wt%. All samples were incubated during 219 days.The results indicated that soil amendment with biochars decreased the carbon mineralization, in contrast to soil amended with the pig manure. Addition of pig manure increased dehydrogenase, phosphomonoesterase and phosphodiesterase activities, while B prepared at 300 °C resulted on a positive effect on dehydrogenase activity. In contrast, B prepared at 500 °C did not exhibit a positive effect on soil enzyme activity.