Effects of solid oxygen fertilizers and biochars on nitrous oxide production from agricultural soils in Florida.

Elevated levels of nitrous oxide (NO) emissions are a matter of concern in agricultural soils especially when flooding (hypoxic conditions) results from over irrigation or frequent rains. This study is the first to report the use of two solid oxygen fertilizers (SOFs, calcium peroxide and magnesium peroxide) to reduce NO production in mineral and organic soils amended with N fertilizer in a short-term laboratory incubation besides two biochars. In general, organic soil had greater NO production than mineral soil.

Duration and frequency of drainage and flooding events interactively affect soil biogeochemistry and N flux in subtropical peat soils.

With the demand for restoration and future prediction of climate change effects, subtropical peatlands are expected to be subjected to hydrologic regimes with variable duration and frequency of drained and flooded conditions, but knowledge of their interactive effects on soil biogeochemistry and emission of greenhouse gases including nitrous oxide (NO) is largely limited. The objective of this study was to investigate how the duration and frequency of drainage and flooding events interactively influence soil biogeochemical properties and denitrification and related net NO production rates following rewetting. Surface soils are susceptible to different hydrologic regimes.

Influence of select bioenergy by-products on soil carbon and microbial activity: A laboratory study.

Concerns about the negative impacts of crop biomass removal on soil ecological functions have led to questioning the long-term sustainability of bioenergy production. To offset this potential negative impact, use of organic C rich by-products from the bioenergy industries have been proposed as a means to replenish soil C in degraded soils. However, the impact of these by-products application on soil carbon dynamics is not fully understood.

Rate of warming affects temperature sensitivity of anaerobic peat decomposition and greenhouse gas production.

Temperature sensitivity of anaerobic carbon mineralization in wetlands remains poorly represented in most climate models and is especially unconstrained for warmer subtropical and tropical systems which account for a large proportion of global methane emissions. Several studies of experimental warming have documented thermal acclimation of soil respiration involving adjustments in microbial physiology or carbon use efficiency (CUE), with an initial decline in CUE with warming followed by a partial recovery in CUE at a later stage. The variable CUE implies that the rate of warming may impact microbial acclimation and the rate of carbon-dioxide (CO ) and methane (CH ) production.

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

In the event of increased frequency of extreme wet or dry events resulting from climate change, it becomes more important to understand the temporal dynamics of soil nitrogen (N) processes in ecosystems. Here, seasonal patterns of N cycling were characterized in subtropical wetlands in Everglades National Park, Florida, USA. Two restored sites and one reference site with different nutrient status, soil depth, and vegetation communities, were selected.