Phosphorus (P) is a finite resource and an essential macronutrient for plant growth. The importance of low soil P availability in constraining plant biomass responses to elevated CO 2 (eCO 2 ) is increasingly recognized. P fertilization could alleviate these constraints, but biogeochemical feedbacks under eCO 2 may diminish the effectiveness of P fertilizer in raising soil P availability. Here, we present data from a botanical...

Simulation models are extensively used to predict agricultural productivity and greenhouse gas emissions. However, the uncertainties of (reduced) model ensemble simulations have not been assessed systematically for variables affecting food security and climate change mitigation, within multi‐species agricultural contexts. We report an international model comparison and benchmarking exercise, showing the potential of multi‐mode...

Ecosystem models play a crucial role in understanding and evaluating the combined impacts of rising atmospheric CO 2 concentration and changing climate on terrestrial ecosystems. However, we are not aware of any studies where the capacity of models to simulate intra‐ and inter‐annual variation in responses to elevated CO 2 has been tested against long‐term experimental data. Here we tested how well the ecosystem model APSIM/Ag...

Our limited understanding of terrestrial ecosystem responses to elevated CO 2 is a major constraint on predicting the impacts of climate change. A change in botanical composition has been identified as a key factor in the CO 2 response with profound implications for ecosystem services such as plant production and soil carbon storage. In temperate grasslands, there is a strong consensus that elevated CO 2 will result in a great...

The increasing concentration of atmospheric carbon dioxide (CO 2 ) is expected to lead to enhanced competition between plants and microorganisms for the available nitrogen (N) in soil. Here, we present novel results from a 15 N tracing study conducted with a sheep‐grazed pasture soil that had been under 10 years of CO 2 enrichment. Our study aimed to investigate changes in process‐specific gross N transformations in a soil pre...

We used the New Zealand grazed pasture free air CO 2 enrichment experiment to determine the effects of elevated CO 2 on earthworm ( Aporrectodea caliginosa and Lumbricus rubellus ) cast production and mineral nitrogen (N) concentration over a 5‐week period in the spring. Elevated CO 2 did not affect earthworm biomass or the amount of cast material produced. However, cast mineral N concentrations were 18% lower, resulting in 27...

The effects of elevated atmospheric CO 2 (475 μL L −1 ) on in situ decomposition of plant litter and animal faecal material were studied over 2 years in a free air CO 2 enrichment (FACE) facility. The pasture was grazed by sheep and contained a mixture of C 3 and C 4 grasses, legumes and forbs. There was no effect of elevated CO 2 on decomposition within plant species but marked differences between species with faster decompos...

In pastures grazed by large herbivores, nutrients cycle both through litter and animal excreta. We compared nitrogen (N) returns from sheep grazing a temperate pasture exposed to ambient or elevated CO 2 (475 μmol mol −1 ) in a FACE (Free Air CO 2 Enrichment) experiment established in the spring of 1997. In the spring of 2000 and 2001, we measured the chemical composition of the diet, sheep faeces and of individual plant speci...

Over time, the stimulative effect of elevated CO 2 on the photosynthesis of rice crops is likely to be reduced with increasing duration of CO 2 exposure, but the resultant effects on crop productivity remain unclear. To investigate seasonal changes in the effect of elevated CO 2 on the growth of rice ( Oryza sativa L.) crops, a free air CO 2 enrichment (FACE) experiment was conducted at Shizukuishi, Iwate, Japan in 1998–2000....