Growth and nitrogen uptake of CO₂‐enriched rice under field conditions

Abstract

Summary• The effects of elevated CO 2 are reported here on the uptake of nitrogen (N) and its relationships with growth and grain yield in rice ( Oryza sativa ).• Using free-air CO 2 enrichment (FACE), rice crops were grown at ambient or elevated ( c . 300 µ mol mol -1 above ambient) CO 2 and supplied with low, medium or high levels of N.• For the medium and high N treatments, FACE increased N uptake at panicle initiation but not at maturity. For total dry matter, as well as spikelet number and grain yield, positive interactions between CO 2 and N uptake were observed. Furthermore, spikelet number was closely associated with N uptake at panicle initiation.• These results indicate that, to maximize rice grain yield under elevated CO 2 , it is important to supply sufficient N over the whole season, in order to maintain the enhancement in dry matter production. In addition, N availability must be coordinated with the developmental stage of the crop, specifically to ensure that sufficient N is available at panicle initiation in order to maximize spikelet number and grain yield.

Effect of CO2Enrichment on the Translocation and Partitioning of Carbon at the Early Grain-filling Stage in Rice (Oryza sativaL.)

“…Our fi nding that ear weight was increased by CO 2 enrichment agrees with previous reports (Kimball, 1983(Kimball, , 1986Kim et al, 2001). Although increased photosynthesis has been reported under long-term CO 2 enrichment (Baker et al, 1990b;Monje and Bugbee, 1998;Sakai et al, 2001), the infl uence of CO 2 enrichment on carbohydrate translocation has been reported by only a few researchers (e.g., Grüters, 1999).…”

“…In another study conducted in a paddy fi eld (Kim et al, 2001), the amount of 13 C translocated to the roots was less than 1 % of the 13 C supplied at the time of heading (data not shown). We also measured the amount of fallen leaves every 30 days, but the data cannot be presented here, because the difference between plants grown under normal and CO 2 -enriched conditions was so small and because the amount of leaves fallen during the 9-day study period was negligible in our analysis of 13 C translocation.…”

“…Although effects of CO 2 enrichment on the fi nal grain yield have been reported (Kimball, 1983(Kimball, , 1986Kim et al, 2001), its infl uence on grain-fi lling has not been investigated in detail. The balance between source and sink was thought to determine carbohydrate storage in the grains during the grain-fi lling stage (Ho, 1988).…”

Assessment of climate change impact on Eastern Washington agriculture

“…However, biomass gains from CO 2 elevation can be preserved if ample N is supplied to crops. Kim et al (2001) grew rice in a FACE experiment and found that, to maximize rice grain yield under elevated CO 2 , it was important to supply sufficient N over the whole season. The implication for agriculture is the need to increase crop fertilization to ensure that growth enhancement by CO 2 will not be limited by nutrient supply.…”

Effects of elevated CO2 on the nutrient compositions and enzymes activities of Nilaparvata lugens nymphs fed on rice plants

“…Yin [9] reported that both leaf mass-based N content and specific leaf area decreased under elevated CO 2 in their meta-analysis of 62 species. Kim et al [10] recommended that a sufficient supply of N be maintained over the entire rice growing season to maintain increased dry matter production and thus maximize grain yields under enriched CO 2 . Wu et al [11] reported that CO 2 level significantly influenced foliar total amino acids in cotton plants, and foliar protein content significantly decreased under elevated CO 2 compared with ambient CO 2 .…”