GREENHOUSE GAS EMISSIONS FROM AN ALKALINE SALINE SOIL CULTIVATED WITH MAIZE (ZEA MAYS L.) AND AMENDED WITH ANAEROBICALLY DIGESTED COW MANURE: A GREENHOUSE EXPERIMENT

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.

Keywords:

• concentrations of NH⁺ ₄
• NO⁻ ₂ and NO⁻ ₃
• emission of CO₂ and N₂O
• plant development
• pH and electrolytic conductivity in soil

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.