Controls on soil arylsulfatase activity at a regional scale

Abstract

Soil arylsulfatase (ARS) is an important enzyme that controls the acquisition of organic sulfur and thus the soil sulfur cycling. However, compared to those enzymes that involved in the acquisition of organic carbon, nitrogen, and phosphorus, ARS activity and its regulations have rarely been investigated. Here, a regional-scale investigation on soil ARS activity was conducted in southwest China to determine the major controls on soil ARS activity. Results showed that soil ARS activity increased from cropland through to forest following post-agriculture succession, and was significantly lower in clasolite than in dolomite or limestone. Among 14 studied soil variables, five variables (i.e. soil pH, exchangeable calcium, organic carbon, clay and silt) showed significant relationships with ARS activity, and these relationships were non-linear. Path analysis further showed that the activity of soil ARS was most controlled by soil pH and soil texture, but soil calcium and organic carbon only had indirect or spurious effects on ARS activity. Differing from most previous studies that used linear analysis, our results highlight that non-linear analysis is a better way for exploring the controlling factors of soil ARS activity, and we suggest that at the regional scale, soil pH and soil texture may be the most sensitive indicators of soil ARS activity.