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Elevated Carbon Dioxide and Soil Moisture on Early Growth Response of Soybean

“…The reason attributed to the uptake of nutrient from the soil is not increased in relation to the increased net carbon assimilation may leading to changes in the nutritional quality of the crops. High C:N ratio due to elevated [CO 2 ] has been reported in various investigations [15] [16]. On the other hand no significant effect of soil moisture and the interactions was found on carbon, nitrogen and C:N ratio of soybean leaf.…”

“…The direct impact of rising atmospheric [CO 2 ] concentration on plants includes increase in photosynthetic rate [4]- [6], growth [7]- [9], reduction in nutrient concentration of plants [10] [11], reduction in leaf nitrogen concentration [12]- [14], increased C:N ratio [15] [16] and increased flowering and fruiting [15]- [21], and yield of agricultural crops [2] [22] [23], and is also expected to increase water use efficiency of crops [2] [4]. Productivity of most agricultural crops increases under elevated [CO 2 ] is in the range of 15% to 41% for C3 crops and 5% to 10% for C4 crops [2] [22] [23].…”

Nitrogen enrichment lowers Betula pendula green and yellow leaf stoichiometry irrespective of effects of elevated carbon dioxide

“…Despite emission reduction in some parts of Western Europe since the 1990s, nitrogen (N) emission levels are still expected to rise in other parts of the world (Dentener et al 2006). The general effects of elevated CO 2 on C 3 plants include increased photosynthesis, water use efficiency, net primary production (NPP), and decreased N concentration (or an increased C:N ratio; Pettersson and McDonald 1992;Ceulemans and Mousseau 1994;Mcguire et al 1995;Penuelas and Estiarte 1997;Poorter et al 1997;Curtis and Wang 1998;Gifford et al 2000;DeLucia and Thomas 2000;Norby et al 2001;Finzi et al 2002;Coley et al 2002). Because N availability limits plant growth in many terrestrial ecosystems, an increase in N availability generally has a positive effect on plant growth and/or biomass, total plant N, area-based plant N concentration, and specific leaf area Bauer et al 2001;Lipson and Nasholm 2001;Pal et al 2005; van den Berg et al 2005b;Reich et al 2006).…”

“…The effects of elevated CO 2 and increased N availability on tree litter quality can be opposite and are therefore not yet fully understood. While yellow leaf C:N may be unaffected or positively affected by elevated CO 2 , it may be unaffected to negatively affected in response to increased N availability (Cotrufo et al 1995;Hirschel et al 1997;Scherzer et al 1998;Norby et al 1999;Gifford et al 2000;Norby et al 2001). Some studies on deciduous tree species have investigated both factors in combination, but most often the emphasis was solely on primary production and yellow leaf C:N values have not been reported (Pettersson et al 1993;Mcguire et al 1995;Bauer et al 2001).…”

Modelling the response of yields and tissue C : N to changes in atmospheric CO<sub>2</sub> and N management in the main wheat regions of western Europe

“…While some studies have found elevated CO 2 to also change the chemical composition of the plants and thus the C : N (Yin, 2002), others (e.g. Gifford et al, 2000) found no evidence of changes in the C : N of the senesced leaves grown under higher [CO 2 ] implying that the fixed C : N limits and in turn the N b are valid also under elevated [CO 2 ], but this remains to be explored.…”