Plant plasticity in intercropping: mechanisms and consequences

J. Zhu

Research output: Thesisinternal PhD, WU

Abstract

Abstract

Diverse agricultural system such as intercrop is practised widely in developing countries and is gaining increasing interest for sustainable agriculture in developed countries. Plants in intercrops grow differently from plants in single crops, due to interspecific plant interactions and heterogeneous resource distribution, but adaptive plant morphological responses to competition in intercrops have not been studied in detail. This thesis aims to link the performance of an intercropping system with plasticity in plant traits.

Grain yield of border-row wheat of an intercrop was 141% higher than in sole wheat. The yield increase was mainly associated with plasticity in tillering and leaf sizes. Compared to maize in monoculture, maize in intercrops had lower leaf and collar appearance rates, larger blade and sheath sizes at low ranks and smaller ones at high ranks. The data suggest many of those changes are linked to each other through feedback mechanisms both at plant level and at phytomer level. A model of maize development was further developed based on three coordination rules between leaf emergence events and dynamics of organ extension. Flexible timing of organ development can emerge from the model as well as the distribution of leaf sizes over ranks. A wheat-maize architectural model was developed for quantifying the role of architectural trait plasticity in light capture in intercrop. Simulated light capture was 23% higher in intercrop with plasticity in traits than the expected value weighted from the light capture in sole crops. Thirty-six percentage of the light increase was due to intercrop configuration alone and 64% was due to plasticity.

Overall, this thesis clearly shows the importance of plasticity in architectural traits for overyielding in wheat-maize intercropping and probably in diversified cropping systems in general. Thus it points to a previously under-appreciated mechanism driving the relationship between species diversity and overyielding of plant communities.

 

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • Anten, Niels, Promotor
  • Evers, Jochem, Co-promotor
  • van der Werf, Wopke, Co-promotor
Award date8 Jan 2015
Place of PublicationWageningen
Publisher
Print ISBNs9789462572195
Publication statusPublished - 2015

Keywords

  • intercropping
  • plant competition
  • simulation models

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