Yield, growth and grain nitrogen response to elevated CO2 of five field pea (Pisum sativum L.) cultivars in a low rainfall environment

Water availability moderates N2 fixation benefit from elevated [CO2]: A 2‐year free‐air CO2 enrichment study on lentil (Lens culinaris MEDIK.) in a water limited agroecosystem

“…In legumes, the known decrease in grain [N] under e[CO 2 ] is less prevalent than in non‐legume crops (Myers et al, ), and we found that e[CO 2 ] decreased grain [N] by 4%, but only in the dry season. Decreases in grain [N] under e[CO 2 ] in a low rainfall environment were previously observed in lentil and field pea (Bourgault et al, ; Bourgault et al, ). In the high rainfall season, stimulation of N 2 fixation by e[CO 2 ] was apparently sufficient to maintain grain [N] with higher yield, similar to reports in soybean in high rainfall agroecosystems (Gray et al, ) and supported by the positive correlation between grain [N] and N deposition to grain from fixation (Figure ).…”

“…When acquisition of both soil and atmospheric N 2 sources is limited during grain filling, remobilization of N from the pre-existing N pool in the vegetative tissues can become the major source of N for seeds (Salon et al, 2001;Vikman & Vessey, 1992 were previously observed in lentil and field pea (Bourgault et al, 2017;Bourgault et al, 2016). In the high rainfall season, stimulation of N 2 fixation by e[CO 2 ] was apparently sufficient to maintain grain…”

“…Apart from growth and yield response, differences in N 2 fixation ability in response to e[CO 2 ] would be a useful candidate trait for selecting genotypes for a carbon‐rich environment. Genotypic variability in terms of N 2 fixation enhancement and maintaining grain [N] under e[CO 2 ] has been reported for soybean (Lam, Hao, et al, ; Li et al, ) and for field pea (Bourgault et al, ).…”

“…Water availability can also determine the ability of legumes to maintain grain [N] by moderating N 2 fixation. For example, in high rainfall conditions, soybeans maintained grain [N] under e[CO 2 ] (Gray et al, ), but experiments in semi‐arid environments showed small but significant decreases in grain protein concentration of lentil (Bourgault et al, ), field pea (Bourgault, Brand, Tausz, & Fitzgerald, ), and chickpea (Lam, Chen, Norton, & Armstrong, ). Such interactions with environmental conditions highlight the importance of assessing and better understanding N 2 fixation under e[CO 2 ] in water limited agroecosystems.…”

“…Selection of genotypes that are more responsive to e[CO 2 ] attracts interest as a potential foundation for crop breeding (Tausz et al, 2013;Ziska et al, 2012). For legumes, intraspecific variability in grain yield response to e[CO 2 ] has been reported for soybean (Bishop, Betzelberger, Long, & Ainsworth, 2015), common bean (Bunce, 2008), and cowpea ( has been reported for soybean (Lam, Hao, et al, 2012;Li et al, 2017) and for field pea (Bourgault et al, 2016).…”