Ammonia-oxidizing bacteria and ammonia-oxidizing archaea are commonly found together in soils, yet the factors influencing their relative distribution and activity remain unclear. We examined archaeal and bacterial amoA gene distribution, and used a novel bioassay to assess archaeal and bacterial contributions to nitrification potentials in soils spanning a range of land uses (forest, pasture, ...

Members of the phylum Acidobacteria are among the most abundant soil bacteria on Earth, but little is known about their response to environmental changes. We asked how the relative abundance and biogeographic patterning of this phylum and its subgroups responded to forest-to-pasture conversion in soils of the western Brazilian Amazon. Pyrosequencing of 16S rRNA genes was employed to assess the ...

Winter is a very important period during the dairying calendar. Regions such as Southland, with susceptible soils and extended periods with soils at saturation levels will face increasing pressure to review wintering practices. On-farm options for wintering cows to protect soils and prevent pasture damage are needed. This requires a turn-around in philosophy from taking cows to pasture/crops, t...

The Cerrado region, with over 50 million hectares of cultivated pasture, provides 55% of Brazilian beef production. Previous investigations have shown that about 70-80% of this pasture is affected by some kind of degradation, leading to low productivity. However, until now, few surveys have been carried out on a regional scale. The aim of the present work is both to assess the fertility and aci...

A method was developed to determine the contributions of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) to the nitrification potentials (NPs) of soils taken from forest, pasture, cropped, and fallowed (19 years) lands. Soil slurries were exposed to acetylene to irreversibly inactivate ammonia monooxygenase, and upon the removal of acetylene, the recovery of nitrification p...

We investigated the effects of land-use changes on soil carbon storage and soil CO2 flux by comparing soils from mature cloud forest and 31-year-old secondary forest, both in the Santa Elena Forest Reserve, a municipallyowned reserve at an elevation of 1600 to 1700 m near the town of Monteverde, and a clear-cut pasture near the reserve. Soils in the mature forest exhibit only weak horizonation ...

Proper pasture management is important in promoting optimal forage growth and reducing runoff and nutrient loss. Pasture renovation is a management tool that improves aeration by mechanically creating holes or pockets within the soil. Pasture renovation was performed before manure application (poultry litter or swine slurry) on different pasture soils and rainfall simulations were conducted to ...

This study aimed to assess the feasibility of predicting ranges in N2O emission with a boundary line approach using a few key driving factors. Intact soil cores (9 cm dia. and ~20 cm in depth) were collected from pasture, cereal cropping and sugarcane lands and incubated at various temperature and moisture conditions after addition of different forms of mineral nitrogen (NH4 and NO3). The pastu...

Largely influenced by the passage of the Swamp Land Act of 1849, many wetlands were lost in the coastal plain region of the southeastern United States, primarily as a result of drainage for agricultural activities. To better understand the chemical response of soils during wetland conversion, soil core samples were collected from the converted beef cattle pastures and from the natural wetland a...

Physical, chemical, biochemical and microbial properties of riparian soils beneath native scmb (Leptospermum scoparium), grazed pasture, and set-aside pasture along the edge of a third order stream near Taupo, New Zealand were compared. In the 12 years since retirement from grazing, dominant vegetation in the set-aside areas changed from pasture grasses to native tussock (Poa cita). Riparian se...