Temperate agroforestry can offer numerous environmental benefits over open croplands, including improved soil health. Recent studies suggest that adequate nutrient management (i.e., reduced fertilizer inputs) in agroforestry systems may even further improve their environmental performance. We conducted a 4-year fertilization experiment (regular vs. reduced mineral fertilization) in a paired short-rotation poplar alley-cropping...

Field-based quantification of soil greenhouse gas emissions from the Philippines’ agriculture sector is missing for vegetable production systems, despite its substantial contribution to agricultural production. We quantified soil N 2 O emission, CH 4 uptake, and CO 2 efflux in vegetable farms and compared these to the secondary forest. Measurements were conducted for 13 months in 10 smallholder farms and nine forest plots on A...

Experimental evidence of nutrient limitations on primary productivity in Afrotropical forests is rare and globally underrepresented yet are crucial for understanding constraints to terrestrial carbon uptake. In an ecosystem‐scale nutrient manipulation experiment, we assessed the early responses of tree growth rates among different tree sizes, taxonomic species, and at a community level in a humid tropical forest in Uganda. Fol...

Efficient use of nutrients is a key requisite for a sustainable intensification of agriculture in order to meet the increasing global crop demand while minimizing deleterious environmental impacts. Agroforestry systems exhibit tree–crop interactions, which potentially contribute to nutrient-efficient agro-ecosystems. Our goal was to determine whether the conversion from cropland monocultures to alley-cropping agroforestry incr...

Large areas in the tropics receive elevated atmospheric nutrient inputs. Presently, little is known on how nitrogen (N) cycling in tropical montane forest soils will respond to such increased nutrient inputs. We assessed how gross rates of mineral N production (N mineralization and nitrification) and microbial N retention (NH 4 + and NO 3 − immobilization and dissimilatory NO 3 − reduction to NH 4 + [DNRA]) change with elevate...

Although the canopy can play an important role in forest nutrient cycles, canopy‐based processes are often overlooked in studies on nutrient deposition. In areas of nitrogen (N) and phosphorus (P) deposition, canopy soils may retain a significant proportion of atmospheric inputs, and also receive indirect enrichment through root uptake followed by throughfall or recycling of plant litter in the canopy. We measured net and gros...

Nitrogen deposition is projected to increase rapidly in tropical ecosystems, but changes in soil‐N‐cycling processes in tropical ecosystems under elevated N input are less well understood. We used N‐addition experiments to achieve N‐enriched conditions in mixed‐species, lowland and montane forests in Panama. Our objectives were to (1) assess changes in soil mineral N production (gross rates of N mineralization and nitrificatio...

Agroforestry systems may play a critical role in reducing the vulnerability of farmers' livelihood to droughts as tree‐based systems provide several mechanisms that can mitigate the impacts from extreme weather events. Here, we use a replicated throughfall reduction experiment to study the drought response of a cacao/ Gliricidia stand over a 13‐month period. Soil water content was successfully reduced down to a soil depth of a...

Tropical nitrogen (N) deposition is projected to increase substantially within the coming decades. Increases in soil emissions of the climate‐relevant trace gases NO and N 2 O are expected, but few studies address this possibility. We used N addition experiments to achieve N‐enriched conditions in contrasting montane and lowland forests and assessed changes in the timing and magnitude of soil N‐oxide emissions. We evaluated tr...

In the next few decades, climate of the Amazon basin is expected to change, as a result of deforestation and rising temperatures, which may lead to feedback mechanisms in carbon (C) cycling that are presently unknown. Here, we report how a throughfall exclusion (TFE) experiment affected soil carbon dioxide (CO 2 ) production in a deeply weathered sandy Oxisol of Caxiuanã (Eastern Amazon). Over the course of 2 years, we measure...

A network of long‐term monitoring sites on nitrogen (N) input and output of forests across Germany showed that a number of Germany's forests are subject to or are experiencing N saturation and that spruce ( Picea abies ) stands have high risk. Our study was aimed at (1) quantifying the changes in gross rates of microbial N cycling and retention processes in forest soils along an N enrichment gradient and (2) relating the chang...

Currently, it is unknown what role tropical forest soils will play in the future global carbon cycle under higher temperatures. Many tropical forests grow on deeply weathered soils and although it is generally accepted that soil carbon decomposition increases with higher temperatures, it is not known whether subsurface carbon pools are particularly responsive to increasing soil temperatures. Carbon dioxide (CO 2 ) diffusing ou...

Contrary to large areas in Amazonia of tropical moist forests with a pronounced dry season, tropical wet forests in Costa Rica do not depend on deep roots to maintain an evergreen forest canopy through the year. At our Costa Rican tropical wet forest sites, we found a large carbon stock in the subsoil of deeply weathered Oxisols, even though only 0.04–0.2% of the measured root biomass (>2 mm diameter) to 3 m depth was below 2...