Abstract

Without new innovations, present rates of increase in yields of food crops globally are inadequate to meet the projected rising food demand for 2050 and beyond. A prevailing response of crops to rising [CO2] is an increase in leaf area. This is especially marked in soybean, the world's fourth largest food crop in terms of seed production, and the most important vegetable protein source. Is this increase in leaf area beneficial, with respect to increasing yield, or is it detrimental? It is shown from theory and experiment using open-air whole-season elevation of atmospheric [CO2] that it is detrimental not only under future conditions of elevated [CO2] but also under today's [CO2]. A mechanistic biophysical and biochemical model of canopy carbon exchange and microclimate (MLCan) was parameterized for a modern US Midwest soybean cultivar. Model simulations showed that soybean crops grown under current and elevated (550 [ppm]) [CO2] overinvest in leaves, and this is predicted to decrease productivity and seed yield 8% and 10%, respectively. This prediction was tested in replicated field trials in which a proportion of emerging leaves was removed prior to expansion, so lowering investment in leaves. The experiment was conducted under open-air conditions for current and future elevated [CO2] within the Soybean Free Air Concentration Enrichment facility (SoyFACE) in central Illinois. This treatment resulted in a statistically significant 8% yield increase. This is the first direct proof that a modern crop cultivar produces more leaf than is optimal for yield under today's and future [CO2] and that reducing leaf area would give higher yields. Breeding or bioengineering for lower leaf area could, therefore, contribute very significantly to meeting future demand for staple food crops given that an 8% yield increase across the USA alone would amount to 6.5 million metric tons annually.

Original languageEnglish (US)
Pages (from-to)1626-1635
Number of pages10
JournalGlobal Change Biology
Volume23
Issue number4
DOIs
StatePublished - Apr 1 2017

Fingerprint

Crops
crop
leaf area
soybean
food
cultivar
experiment
Common Bile Duct Diseases
Anthralin
Seed
bioengineering
seed production
microclimate
crop yield
vegetable
innovation
breeding
canopy
seed
productivity

Keywords

  • climate change
  • crop bioengineering
  • ecohydrology
  • food security
  • plant breeding
  • rising CO

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • Environmental Science(all)

Cite this

Decreasing, not increasing, leaf area will raise crop yields under global atmospheric change. / Srinivasan, Venkatraman; Kumar, Praveen; Long, Stephen P.

In: Global Change Biology, Vol. 23, No. 4, 01.04.2017, p. 1626-1635.

Research output: Contribution to journalArticle

Srinivasan, Venkatraman; Kumar, Praveen; Long, Stephen P. / Decreasing, not increasing, leaf area will raise crop yields under global atmospheric change.

In: Global Change Biology, Vol. 23, No. 4, 01.04.2017, p. 1626-1635.

Research output: Contribution to journalArticle

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