Soil enzyme responses to varying rainfall regimes in Chihuahuan Desert soils

Abstract

Abstract. Extracellular enzyme activities (EEAs) are indicators of both soil microbial activity and nutrient availability for plants. However, it is unclear how EEAs change over the growing season in desert grasslands. We examined whether EEAs changed in response to the size and frequency of rain events during the summer monsoon in the northern Chihuahuan Desert, and if the response varied between plant and interspace associated soils. Potential EEAs were measured within a rainfall manipulation experiment at the Sevilleta National Wildlife Refuge in central New Mexico, USA. Rainfall treatments included either three 10-mm events or one 30-mm rain event per month throughout the three month summer monsoon (July-September). EEAs were measured immediately before and within hours after experimental rain events under plants and in unvegetated interspaces. Throughout the season hydrolase activities were higher under vegetation than in interspace soils. Potential activities of hydrolytic enzymes were similar for the two rainfall regimes. Activities increased following early season rain, showed little response to midseason rain, and decreased following late-season rain. Although enzyme activities did not differ between rainfall treatments, ratios between enzymes varied, indicating different nutrient limitations imposed by rain event size and frequency. Larger nitrogen and phosphorus limitations occurred in interspace soils that experienced large, frequent rain events. Many factors, including location relative to plants, seasonality, and rainfall size and frequency, influenced enzyme activities and nutrient availability in these Chihuahuan Desert soils throughout the monsoon season.

Seasonal patterns of nitrogen cycling in subtropical short-hydroperiod wetlands: Effects of precipitation and restoration

“…By altering soil water content, rainfall not only influences microbial activity, but probably also affects N availability via plant-microbe interaction (Ladwig et al, 2015). Under the same precipitation regime, soil water content varies with soil depth, soil texture, and vegetation coverage (Peters et al, 1995;Reynolds et al, 2004).…”

“…Under the same precipitation regime, soil water content varies with soil depth, soil texture, and vegetation coverage (Peters et al, 1995;Reynolds et al, 2004). Moreover, due to various sensitivity of different N processes to the changes of soil water content, the frequency and intensity of rainfall will fine-tune the temporal patterns of N cycling (Fierer and Schimel, 2002;Austin et al, 2004;Ladwig et al, 2015).…”

Dynamic characteristics of soil properties in a Robinia pseudoacacia vegetation and coastal eco-restoration

“…Following the onset of rainfall season, R. pseudoacacia grew rapidly. A lot of labile compounds would be exuded through roots and residue of plants (Geisseler et al, 2011), which led to the increase of soil organic matter (Ladwig et al, 2015). Therefore, the increase of soil organic matter in this paper was correlated with the growth of R. pseudoacacia.…”

“…This can be explained with the report that under waterlogging condition, enzyme activities were impeded (Kang and Freeman, 1999). Variations on precipitation have been suggested to possess significant effects on enzyme activities (Munson et al, 2010;Ladwig et al, 2015). Salinity also has a powerful influence on soil enzyme activities.…”

“…The changes of soil nutrients are strongly related with plants and abiotic environments (Ladwig et al, 2015). Following the onset of rainfall season, R. pseudoacacia grew rapidly.…”