CO2 emission from soil irrigated with recycled wastewater at different levels and the relationships of emission with soil properties

Abstract

The use of recycled wastewater in agricultural irrigation contributes to ecosystem by reducing the discharge of wastewater to the environment, as well as increasing soil quality with fertilizing effect. However, since the high nutrient of wastewater can make the soil a source of CO2 emission, it is necessary to know the relationships between CO2 emission and soil properties to the management of emissions. This study aimed to determine the relationships between CO2 emission and soil properties by examining the changes in the properties of soil irrigated with recycled wastewater and freshwater at different levels. The results showed that the recycled wastewater caused 58.1% more CO2 emissions than freshwater in full irrigation treatments, while the emissions decreased in the range of 8.8% to 44.5% with increased deficit irrigation. In addition, the significant relationships of CO2 emission with EC, pH, CaCO3, organic matter, total N, P2O5, K2O, cation exchange capacity, porosity, aggregate stability properties of the soil and H2O emission from the soil, soil moisture and temperature at different depths were determined, demonstrated the effectiveness of these parameters in the management of CO2 emissions in soil irrigated with recycled wastewater. Considering the obtained findings, it was determined that deficit irrigation is very effective in reducing CO2 emission and considering the effectiveness of soil temperature and soil properties on the emissions, CO2 emission can be reduced by soil temperature and soil properties management, and more comprehensive studies on this subject could suggest.