HOW MULTISPECIES INTERCROP ADVANTAGE RESPONDS TO WATER STRESS: A YIELD-COMPONENT ECOLOGICAL FRAMEWORK AND ITS EXPERIMENTAL APPLICATION

Highlights

● A framework for multicrop advantage under varying watering conditions is provided.

● This framework clarifies the relation between multicrop overyielding and land use efficiency.

● A novel experimental setup was used to evaluate these theoretical developments.

● Theory and experiment conveyed precise understanding of overyielding scenarios.

Abstract

Absolute yield and land use efficiency can be higher in multicrops. Though this phenomenon is common, it is not always the case. Also, these two benefits are frequently confused and do not necessarily occur together. Cropping choices become more complex when considering that multicrops are subject to strong spatial and temporal variation in average soil moisture, which will worsen with climate change. Intercropping in agroecosystems is expected to buffer this impact by favoring resistance to reduced humidity, but there are few empirical/experimental studies to validate this claim. It is not clear if relatively higher multicrop yield and land use efficiency will persist in the face of reduced soil moisture, and how the relation between these benefits might change. Here, we present a relatively simple framework for analyzing this situation. We propose a relative multicrop resistance (RMR) index that captures all possible scenarios of absolute and relative multicrop overyield under water stress. We dissect the ecological components of RMR to understand the relation between higher multicrop yield and land use efficiency and the ecological causes of different overyield scenarios. We demonstrate the use of this framework with data from a 128 microplot greenhouse experiment with small annual crops, arranged as seven-species multicrops and their corresponding monocrops, all under two contrasting watering regimes. We applied simple but robust statistical procedures to resulting data (based on bootstrap methods) to compare RMR, and its components, between different plants/plant parts. We also provide simple graphical tools to analyze the data.

Graphical abstract

Keywords

agroecosystem sustainability / crop overyielding / intercrop drought resistance / overyield ecological components

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Supplementary materials

The online version of this article at https://doi.org/10.15302/J-FASE-2021412 contains supplementary materials.

Acknowledgements

Hugo Perales-Rivera, Benito Salvatierra-Izaba, Raul García-Barrios, Mario González-Espinosa, Pedro Quintana-Ascencio, and Alejandro Morón-Ríos offered valuable comments on this framework and/or the experiment used to test it. Juan Franco-Pérez, Elías Sántiz-Gómez and Marcos Gómez-López helped to establish, maintain, and harvest the experiment. Duncan Golicher gave valuable advice and support for bootstrap statistical analysis. El Colegio de la Frontera Sur offered working facilities and institutional support. Research was partly funded by the Consejo Nacional de Ciencia y Tecnología (México) through two projects: (1) MESMIS; GIRA, A.C.-UNAM-ECOSUR (2004–2006); Fondos Sectoriales SEMARNAT CONACYT 2002-CO1-0800 and (2) Evaluación de Sustentabilidad de Sistemas Complejos Socio-Ambientales; ECOSUR-UNAM-GIRA (2007–2010); Proyecto de Ciencia Básica 02464.

Compliance with ethics guidelines

Luis Garcia-Barrios and Yanus A. Dechnik-Vazquez declare that they have no conflicts of interest or financial conflicts to disclose. This article does not contain any study with human or animal subjects performed by any of the authors.

RIGHTS & PERMISSIONS

The Author(s) 2021. Published by Higher Education Press. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0)