Carbon Dioxide Emission Rates and β-Glucosidase Activity in Mediterranean Ultisols Under Different Soil Management

Abstract

Soil respiration is the second-largest terrestrial carbon flux, and it has shown to be deeply affected by soil management. This article reports a field and laboratory study comparing CO 2 emission rates from the soil surface and β-glucosidase activity in Mediterranean Ultisols from the Canamero rana surface (continental detritic formations from southwest Spain) under different soil management conditions and vegetation cover: 1) soil in a cork oak grove, the climax vegetation of the studied rana surface; 2) soil in a Cistus scrubland with a 100% cover, uncultived for the past 45 years; 3) soil in a crop field that has been uncultivated for the past 35 years and with 55% of the shrub cover dominated by Cistus crispus L. and the rest covered by pasture; 4) soil in a degraded pastureland; and 5) soil in an olive grove that has been continuously cultivated for the past 65 years. We made a comparative assessment of aerobic activity in each of the soils at different times of the year. The level of degradation of natural vegetation, and therefore also the organic matter content, which decreased from Areas 1 to 5, affected the rate of CO 2 emission from the soil surface. This rate was also affected by soil water content, soil temperature, and the predominance of Cistus ladanifer L. in the soil vegetation cover. In the case of the Olea europaea L. grove soil, the CO 2 emission rate notably increased during autumn in years of high fruit production as a result of increased root respiration. β-Glucosidase activity was mostly, and positively, affected by organic matter content and also was negatively affected by the predominance of C. ladanifer in the vegetation soil cover.