Effects of elevated carbon dioxide and soil nitrogen on growth of two leafy <i>Brassica</i> vegetables

Abstract

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 µ mol/mol, elevated CO 2 562 µ mol/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.