The impacts of precipitation increase and nitrogen addition on soil respiration in a semiarid temperate steppe

Abstract

. 2017. The impacts of precipitation increase and nitrogen addition on soil respiration in a semiarid temperate steppe. Ecosphere 8(1):e01655. 10.1002/ecs2. 1655Abstract. Soil respiration, R s , is strongly controlled by water availability in semiarid grasslands. However, how R s is affected by precipitation change (either as rainfall or as snowfall) especially under increasing nitrogen (N) deposition has been uncertain. A manipulative experiment to investigate the responses of growing season R s to changes in spring snowfall or summer rainfall with or without N addition was conducted in the semiarid temperate steppe of China during three hydrologically contrasting years. Our results showed that both spring snow addition and summer water addition significantly increased R s by increasing soil moisture. The effect of spring snow addition only occurred in years with both relatively lower natural snowfall and later snowmelt time. Summer water addition showed a much stronger effect on R s by increasing plant root growth and microbial activities, but the magnitude also largely depended on the possible legacy effect of previous year precipitation. Our results indicated that precipitation increase in the form of snowfall had weaker effects than that in the form of rainfall as the former only accounted for less than 30% of total precipitation. Compared with other ecosystem processes, R s was less responsible for increase in N deposition as it did not increase root productivity and microbial activities in the soils. Our results provided field data constraints for modeling the ecosystem carbon balance under the future global change scenarios in semiarid grasslands.

Short Legacy Effects of Growing Season Nitrogen Addition and Reduced Precipitation alter Soil Respiration during Nongrowing Season

“…This indicated that the increase in the Ra might be more intense than the increase in Rh under different treatments. Because the trenching method also affects the contributions of Rh to Rs [43], it may be necessary to combine multiple measurement methods to accurately evaluate the contribution of Rh to Rs under climate changes in the future.…”

Ecohydrological processes and ecosystem services in the Anthropocene: a review

“…Changes in the water cycle directly affect ecosystem productivity (Xu et al 2014) and aboveground and belowground carbon cycles through plant transpiration (Sun et al 2011b), soil heat and moisture dynamics that affect ecosystem respiration (Biederman et al 2016;Zhang et al 2017b), and surface and subsurface flows that determine soil water availability to plants. Ecosystems do not generate water, but they modify the quantity, quality, and timing of water cycles.…”

Dryland soils in northern China sequester carbon during the early 2000s warming hiatus period

“…In support of this notion, a recent global analysis illustrated that the net terrestrial C uptake over the warming hiatus period was accelerated owing to the reduced respiration (Ballantyne et al., ). It should be noted that, although precipitation can accelerate soil C decomposition in drylands by increasing microbial biomass and activity (Yang et al., ; Zhang et al., ), the sensitivity of vegetation production to precipitation has been demonstrated to be higher than that of heterotrophic respiration (Poulter et al., ), which could also be conducive to soil C accrual.…”

“…It has been reported that warming could stimulate soil heterotrophic respiration (Jia, Zhou, Wang, Wang, & Wang, 2006;Wu et al, 2010) (Ballantyne et al, 2017). It should be noted that, although precipitation can accelerate soil C decomposition in drylands by increasing microbial biomass and activity Zhang et al, 2017), the sensitivity of vegetation production to precipitation has been demonstrated to be higher than that of heterotrophic respiration (Poulter et al, 2014), which could also be conducive to soil C accrual.…”