Seeking a sound index of competitive intensity: Application to the study of biomass production under elevated CO2 along a nitrogen gradient

The rising atmospheric CO2 concentrations have effects on the worldwide ecosystems such as an increase in biomass production as well as changing soil processes and conditions. Since this affects the ecosystem’s net balance of greenhouse gas emissions, reliable projections about the CO2 impact are required. Deterministic models can capture the interrelated biological, hydrological, and biogeochemical processes under changing CO2 concentrations if long-term observations for model testing are provided. We used 13 years of data on above-ground biomass production, soil moisture, and emissions of CO2 and N2O from the Free Air Carbon dioxide Enrichment (FACE) grassland experiment in Giessen, Germany. Then, the LandscapeDNDC ecosystem model was calibrated with data measured under current CO2 concentrations and validated under elevated CO2. Depending on the hydrological conditions, different CO2 effects were observed and captured well for all ecosystem variables but N2O emissions. Confidence intervals of ensemble simulations covered up to 96% of measured biomass and CO2 emission values, while soil water content was well simulated in terms of annual cycle and location-specific CO2 effects. N2O emissions under elevated CO2 could not be reproduced, presumably due to a rarely considered mineralization process of organic nitrogen, which is not yet included in LandscapeDNDC.

Download Full-text

Pearl millet growth and biochemical alterations determined by mycorrhizal inoculation, water availability and atmospheric CO2 concentration

Crop and Pasture Science ◽

10.1071/cp14089 ◽

2015 ◽

Vol 66 (8) ◽

pp. 831 ◽

Cited By ~ 3

Author(s):

Eliseu G. Fabbrin ◽

Yolanda Gogorcena ◽

Átila F. Mogor ◽

Idoia Garmendia ◽

Nieves Goicoechea

Keyword(s):

Water Content ◽

Pearl Millet ◽

Elevated Co2 ◽

Biomass Production ◽

Water Regime ◽

Soluble Sugars ◽

Co2 Concentration ◽

Atmospheric Co2 ◽

Mycorrhizal Inoculation

Pearl millet (Pennisetum glaucum L.) is an important fodder and is a potential feedstock for fuel ethanol production in dry areas. Our objectives were to assess the effect of elevated CO2 and/or reduced irrigation on biomass production and levels of sugars and proteins in leaves of pearl millet and to test whether mycorrhizal inoculation could modulate the effects of these abiotic factors on growth and metabolism. Results showed that mycorrhizal inoculation and water regime most influenced biomass of shoots and roots; however, their individual effects were dependent on the atmospheric CO2 concentration. At ambient CO2, mycorrhizal inoculation helped to alleviate effects of water deficit on pearl millet without significant decreases in biomass production, which contrasted with the low biomass of mycorrhizal plants under restricted irrigation and elevated CO2. Mycorrhizal inoculation enhanced water content in shoots, whereas reduced irrigation decreased water content in roots. The triple interaction between CO2, arbuscular mycorrhizal fungi (AMF) and water regime significantly affected the total amount of soluble sugars and determined the predominant soluble sugars in leaves. Under optimal irrigation, elevated CO2 increased the proportion of hexoses in pearl millet that was not inoculated with AMF, thus improving the quality of this plant material for bioethanol production. By contrast, elevated CO2 decreased the levels of proteins in leaves, thus limiting the quality of pearl millet as fodder and primary source for cattle feed.

Download Full-text

Interactive effects of elevated CO2 and O3 on photosynthesis and biomass production of clonal 5-year-old Norway spruce [Picea abies (L.) Karst.] under different nitrogen nutrition and irrigation treatments

Trees ◽

10.1007/bf02185642 ◽

1996 ◽

Vol 10 (6) ◽

pp. 382-392 ◽

Cited By ~ 7

Author(s):

Michael Lippert ◽

Karl-Heinz Häberle ◽

Karl Steiner ◽

Hans-Dieter Payer ◽

Karl-Eugen Rehfuess

Keyword(s):

Picea Abies ◽

Norway Spruce ◽

Elevated Co2 ◽

Biomass Production ◽

Nitrogen Nutrition ◽

Interactive Effects ◽

Elevated Co2 And O3 ◽

Irrigation Treatments

Download Full-text

The influence of elevated CO2 and temperature on biomass production of continuously defoliated white clover

Plant Cell & Environment ◽

10.1111/j.1365-3040.1992.tb01493.x ◽

1992 ◽

Vol 15 (5) ◽

pp. 593-599 ◽

Cited By ~ 24

Author(s):

G. J. A. RYLE ◽

C. E. POWELL

Keyword(s):

Elevated Co2 ◽

Biomass Production ◽

White Clover ◽

Elevated Co2 And Temperature

Download Full-text

Climate Change Impacts on Cacao: Genotypic Variation in Responses of Mature Cacao to Elevated CO2 and Water Deficit

Agronomy ◽

10.3390/agronomy11050818 ◽

2021 ◽

Vol 11 (5) ◽

pp. 818

Author(s):

Fiona Lahive ◽

Liam R. Handley ◽

Paul Hadley ◽

Andrew J. Daymond

Keyword(s):

Climate Change ◽

Water Use Efficiency ◽

Water Deficit ◽

Quantum Efficiency ◽

Elevated Co2 ◽

Water Use ◽

Biomass Production ◽

Genotypic Variation ◽

Negative Effect ◽

Use Efficiency

Climate change poses a significant threat to agricultural production in the tropics, yet relatively little research has been carried out to understand its impact on mature tropical tree crops. This research aims to understand the genotypic variation in growth and photosynthesis in mature cacao trees in response to elevated CO2 and water deficit. Six genotypes were grown under greenhouse conditions at ambient (ca. 437 ppm) and elevated CO2 (ca. 724 ppm) and under well-watered and water deficit conditions for 23 months. Leaf- and canopy-level photosynthesis, water-use efficiency, and vegetative growth increased significantly in response to elevated CO2. Water deficit had a significant negative effect on many photosynthetic parameters and significantly reduced biomass production. The negative effect of water deficit on quantum efficiency was alleviated by elevated CO2. Genotypic variation was observed in several parameters including stomatal conductance, stomatal density and index, quantum efficiency, and biomass production, indicating the potential to develop more climate-change-resilient genotypes that can cope with predicted future climate change conditions. Elevated CO2 reduced some of the negative effects of water deficit through changes in water-use efficiency and light utilisation and reduced the negative impact of water deficit on biomass accumulation, but this was genotype-specific.

Download Full-text