Root foraging elicits niche complementarity-dependent yield advantage in the ancient 'three sisters' (maize/bean/squash) polyculture

Chaochun Zhang, Johannes A. Postma, Larry M. York, Jonathan P. Lynch

Research output: Contribution to journalArticlepeer-review

96 Scopus citations

Abstract

Background and Aims Since ancient times in the Americas, maize, bean and squash have been grown together in a polyculture known as the 'three sisters'. This polyculture and its maize/bean variant have greater yield than component monocultures on a land-equivalent basis. This study shows that below-ground niche complementarity may contribute to this yield advantage. Methods Monocultures and polycultures of maize, bean and squash were grown in two seasons in field plots differing in nitrogen (N) and phosphorus (P) availability. Root growth patterns of individual crops and entire polycultures were determined using a modified DNA-based technique to discriminate roots of different species. Key Results The maize/bean/squash and maize/bean polycultures had greater yield and biomass production on a land-equivalent basis than the monocultures. Increased biomass production was largely caused by a complementarity effect rather than a selection effect. The differences in root crown architecture and vertical root distribution among the components of the 'three sisters' suggest that these species have different, possibly complementary, nutrient foraging strategies. Maize foraged relatively shallower, common bean explored the vertical soil profile more equally, while the root placement of squash depended on P availability. The density of lateral root branching was significantly greater for all species in the polycultures than in the monocultures. Conclusions It is concluded that species differences in root foraging strategies increase total soil exploration, with consequent positive effects on the growth and yield of these ancient polycultures.

Original languageEnglish
Pages (from-to)1719-1733
Number of pages15
JournalAnnals of Botany
Volume114
Issue number8
DOIs
StatePublished - Dec 1 2014
Externally publishedYes

Funding

We thank Robert Snyder for technical assistance and Amelia Henry, Macarena Baeza and Patompong Saengwilai for assistance in the field. We are especially grateful to Deb Grove and the Penn State Genomics Core Facility for helping to develop the qPCR technique and running all the DNA samples. C.C.Z. acknowledges support from the National Natural Science Foundation of China (grant number 31210103906) and an Innovative Group grant of the National Natural Science Foundation of China (grant number 31121062). Research costs were supported by the McKnight Foundation CCRP and the USAID-Pulse CRSP. We also thank two anonymous reviewers for their valuable comments and suggestions.

Keywords

  • Bean
  • Cucurbita
  • Intercropping
  • Maize
  • Niche complementarity
  • Nitrogen
  • Phaseolus vulgaris
  • Phosphorus
  • Plant nutrition
  • Polyculture
  • Root architecture
  • Root foraging
  • Squash
  • Three sisters
  • Zea mays

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