Abstract
Sludge derived from cow manure anaerobically digested to produce biogas (methane; CH4) was applied to maize (Zea mays L.) cultivated in a nutrient-low, alkaline, saline soil with electrolytic conductivity 9.4 dS m−1 and pH 9.3. Carbon dioxide (CO2) emission increased 3.1 times when sludge was applied to soil, 1.6 times when cultivated with maize and 3.5 times in sludge-amended maize cultivated soil compared to the unamended uncultivated soil (1.51 mg C kg−1 soil day−1). Nitrous oxide (N2O) emission from unamended soil was -0.0004 μg nitrogen (N) kg−1 soil day−1 and similar from soil cultivated with maize (0.27 μg N kg−1 soil day−1). Application of sludge increased the N2O emission to 4.59 μg N kg−1 soil day−1, but cultivating this soil reduced it to 2.42 μg N kg−1 soil day−1. It was found that application of anaerobic digested cow manure stimulated maize development in an alkaline saline soil and increased emissions of CO2 and N2O.
ACKNOWLEDGMENTS
We thank R. E. A. Nuñez-Rubio and M. A. Petriz-Prieto for operating the bioreactor. The anaerobic digested cow manure was produced as part of a CONCYTEG project (FOMIX.GTO-2006-C01-31722) while the greenhouse experiment was funded by the department of Biotechnology and Bioengineering (Cinvestav, Mexico). F. F.-L. received grant-aided support from CONACYT and J. J.-R. form CONCYTEG.