Drought drives rapid shifts in tropical rainforest soil biogeochemistry and greenhouse gas emissions.

Climate change models predict more frequent and severe droughts in the humid tropics. How drought will impact tropical forest carbon and greenhouse gas dynamics is poorly understood. Here we report the effects of the severe 2015 Caribbean drought on soil moisture, oxygen, phosphorus (P), and greenhouse gas emissions in a humid tropical forest in Puerto Rico.

Perennial grasslands enhance biodiversity and multiple ecosystem services in bioenergy landscapes.

Agriculture is being challenged to provide food, and increasingly fuel, for an expanding global population. Producing bioenergy crops on marginal lands--farmland suboptimal for food crops--could help meet energy goals while minimizing competition with food production. However, the ecological costs and benefits of growing bioenergy feedstocks--primarily annual grain crops--on marginal lands have been questioned.

Initial nitrous oxide, carbon dioxide, and methane costs of converting conservation reserve program grassland to row crops under no-till vs. conventional tillage.

Around 4.4 million ha of land in USDA Conservation Reserve Program (CRP) contracts will expire between 2013 and 2018 and some will likely return to crop production. No-till (NT) management offers the potential to reduce the global warming costs of CO2 , CH4 , and N2 O emissions during CRP conversion, but to date there have been no CRP conversion tillage comparisons.

[Soil N2O flux and its affecting factors under different land use patterns in Three Gorges Reservoir Area of China].

By using static chamber techniques, the N2O emission from soils under different land use patterns was measured. The results showed that the N2O flux ranged from -21 to 435 microg x m(-2) h(-1), and the annual N2O flux was decreased in the order of vegetable field > orchard > upland > upland transferred from paddy field > woodland, being 447.14, 313.

[Variations and influencing factors of nitrate nitrogen concentration in water in a small watershed of Three Gorges area].

In order to study the water quality and response to influencing factors in typical watersheds of Three Gorges area between 2004 and 2005, the variation characteristics of nitrate nitrogen concentration were analyzed under heterogeneous landscape condition through continuous observation with method of dividing into sub-watersheds in Quxi watershed (the first-grade branch, located in Three Gorges). The results suggested that nitrate nitrogen concentration fluctuated between 0.4 and 14.

[CO2 fluxes from red soil under four land use types in mid-subtropical, China].

CO2 fluxes from red soil under different land use (paddy, upland, woodland and orchard) were measured at Xianning city, Hubei province with closed chamber method. The results showed that the annual CO2 emission were 1129, 632, 533, and 828 g/(m2 a) for paddy, upland, woodland, and orchard respectively. Soil CO2 fluxes revealed seasonal fluctuations, with the tendency that maximum value was in summer, minimum was in winter and intermediate in spring and autumn except for paddy soil.