Seasonal Fluctuation of Soil Carbon Dioxide Emission in Differently Managed Pastures

Abstract

Soil carbon dioxide emission (ECO2) is a process determined by biotic and abiotic factors in uenced by land use and management practices. In grassland ecosystems, grazing intensity may a ect C input from plants into soil, and thus may also change soil respiration rate. Indeed, limited information is available regarding the e ects of grazing management on ECO2. is study was conducted to evaluate ECO2 seasonal variation, and its relationship to soil temperature (Tsoil) and precipitation, in an area with di erent pasture heights of Marandu palisade grass [Brachiaria brizantha (A.Rich.) Stapf.]. e pasture heights (15, 25, and 35 cm) were distributed in a completely randomized design with 12 repetitions in each area. e evaluations of ECO2 and Tsoil occurred from January 2011 to February 2013, totaling 73 d of observation that were distributed according to climatic seasons. e results showed that seasonal variation of ECO2 was directly related to variations in precipitation and Tsoil. Soil CO 2 emission was higher in summer and lower in winter. e data variability of ECO2 was higher in rainy, hot summers than in dry, cold winters. A positive linear association between ECO2 and Tsoil was observed in summer and autumn. In most seasons measured, ECO2 reduced with increasing pasture height. Accordingly, 2-yr data indicated that accumulated ECO2 decreased with increasing pasture height. us to better understand the e ect of pasture height on ECO2, a shorter period of measurements is not suitable since a di erent result was observed in the rst year of evaluation.

Cover crop rotations in no-till system: short-term CO2 emissions and soybean yield

“…The lower ECO 2 on the first day after planting are explained in part by the low soil moisture, approximately 0.135 m 3 m -3 in both experiments. After this, rainfall increased ECO 2 with a slight decrease in soil temperature (under 32 °C), suggesting soil moisture was a driving factor of an increase in microbial activity as supported by the finding (Brito et al, 2015). Conversely, when soil moisture is adequate for microbial growth, soil temperature could be an important factor for controlling soil respiration (Carbone et al, 2011).…”

“…Furthermore, irregular rainfall and dry winters hinder the addition of C since the growth of cover crops is impaired and the amount of plant residues produced in the off-season may be reduced (Castro et al, 2015). However, cover crop residues left on the soil surface can decrease the soil temperature, and retain soil moisture and eventually ECO 2 (Brito et al, 2015;Carbone et al, 2011). ECO 2 also depends on the crop rotations used in the agricultural system, which are affected by the quality of crop residue left on the soil and the amount of easily mineralizable C (Kögel-Knabner, 2002).…”

Long‐Term Grazing Alters Soil Trace Gas Fluxes from Grasslands in the Foothills of the Rocky Mountains, Canada

“…Soil moisture and air temperature are important environmental factors controlling soil CO 2 flux, but soil temperature has been consistently more strongly correlated with CO 2 flux from grassland soils than soil moisture (Liebig et al, ; Brito et al, ; Rong et al, ). In our study, soil CO 2 flux was positively correlated with both soil moisture and air temperature, but was more strongly correlated with air temperature.…”

Soil CO2–C Emissions and Correlations with Soil Properties in Degraded and Managed Pastures in Southern Brazil

“…Therefore, better pasture management allowing for an ideal plant height would probably promote greater pasture yields as a result of higher water availability. Additionally, Brito et al () showed that CO 2 –C emissions were lower with increasing pasture height as a result of Brachiaria pasture management.…”