Effects of elevated carbon dioxide and soil nitrogen on growth of two leafyBrassicavegetables

Abstract

Elevated atmospheric carbon dioxide (CO 2 ) increases the instantaneous rate of photosynthesis in C 3 plants. With ample nutrients and water, this so-called 'CO 2 fertilization effect' generally leads to improved growth and production of many plant species that humans use as food. To determine whether increasing CO 2 could be beneficial to growth and yield of leafy Brassica vegetables, trials were established in a Free Air CO 2 Enrichment facility at Horsham, Australia using projected atmospheric CO 2 concentrations for the year 2050. The experiment measured the interacting effects of CO 2 (ambient CO 2 366 mmol/mol, elevated CO 2 562 mmol/mol), nitrogen (low/high) and Brassica rapa cultivars ( ) 2) on shoot growth under south-eastern Australian conditions. For cultivars 'Karate' and 'Chop Suey', significant interaction between elevated CO 2 and a high nitrogen treatment (196 kg/ha) increased the fresh weights of shoots.

Atmospheric CO2 data from the Australian Grains Free Air CO2 Enrichment (AGFACE) facility

“…AGFACE facilities were outdoor laboratories (see Fig. 1 for an example) where the impacts of expected e[CO 2 ] in the year 2050 (550 µmol/mol) on crops were examined [1 , 7 , 8 , 9 , 10 , 11] . The AGFACE facilities were built to understand the impacts of different combinations of irrigation, nitrogen fertilizer and time of sowing (TOS) treatments at two locations and across different soil types under e[CO 2 ] on a range of crops [9] .…”

“…Eight plots under e[CO 2 ] treatment (4-m diameter rings) were established along with eight a[CO 2 ] control plots. The experiment measured the interacting effects of e[CO 2 ], nitrogen (low/high) and two Brassica rapa cultivars on shoot growth under south-eastern Australian conditions [11] .…”

The Influence of Elevated CO2 on Volatile Emissions, Photosynthetic Characteristics, and Pigment Content in Brassicaceae Plants Species and Varieties

“…The data regarding the influence of elevated carbon dioxide on Brassicaceae plants’ characteristics are scarce. An early study showed that two Brassica rapa cultivars grows at 550 ppmv CO 2 showed increased crop productivity, even with the high-end soil nitrogen [ 34 ]. An increase in chlorophyll content of 33% has been found for pak choi ( Brassica rapa ssp.…”

Responses to atmospheric CO2 concentrations in crop simulation models: a review of current simple and semicomplex representations and options for model development

“…), crops and measurements (e.g. Thomson et al, 2013;Zhang et al, 2013;Manderscheid et al, 2014;Fernando et al, 2015). Empirical evidence of major plant responses exists, including stomatal closure and higher light-saturated photosynthesis rates (Ainsworth & Rogers, 2007;Leakey et al, 2009).…”