THE 4 C APPROACH AS A WAY TO UNDERSTAND SPECIES INTERACTIONS DETERMINING INTERCROPPING PRODUCTIVITY

Éric Justes ,Chaochun Zhang ,Georg Carlsson ,Gaëtan Louarn ,C A Watson ,Erik Steen Jensen ,Ela Frak ,Laurent Bedoussac ,Etienne-Pascal Journet ,Anastasios Lithourgidis ,Chrysanthi Pankou ,Simon Boudsocq ,Christos Dordas ,Long Li

doi:10.15302/j-fase-2021414

Abstract

Modern agriculture needs to develop transition pathways toward agroecological, resilient and sustainable farming systems. One key pathway for such agroecological intensification is the diversification of cropping systems using intercropping and notably cereal-grain legume mixtures. Such mixtures or intercrops have the potential to increase and stabilize yields and improve cereal grain protein concentration in comparison to sole crops. Species mixtures are complex and the 4C approach is both a pedagogical and scientific way to represent the combination of four joint effects of Competition, Complementarity, Cooperation, and Compensation as processes or effects occurring simultaneously and dynamically between species over the whole cropping cycle. Competition is when plants have fairly similar requirements for abiotic resources in space and time, the result of all processes that occur when one species has a greater ability to use limiting resources (e.g., nutrients, water, space, light) than others. Complementarity is when plants grown together have different requirements for abiotic resources in space, time or form. Cooperation is when the modification of the environment by one species is beneficial to the other(s). Compensation is when the failure of one species is compensated by the other(s) because they differ in their sensitivity to abiotic stress. The 4C approach allows to assess the performance of arable intercropping versus classical sole cropping through understanding the use of abiotic resources.

Highlights

Diversification of agricultural cropping systems in time and space is recognized as an important strategy for ecological intensification for enhancing sustainability[1,2,3,4]
Species mixtures are complex and the 4C approach is both a pedagogical and scientific way to represent the combination of four joint effects of Competition, Complementarity, Cooperation, and Compensation as processes or effects occurring simultaneously and dynamically between species over the whole cropping cycle
There is abundant of scientific evidence that intercrops often have higher and more stable yields than their respective sole crops[1,6,7,8,9] mostly due to a more efficient use of nutrients, light and water than in sole crops[10,11,12,13]

Summary

INTRODUCTION

Diversification of agricultural cropping systems in time and space is recognized as an important strategy for ecological intensification for enhancing sustainability[1,2,3,4]. Species mixtures or intercrops or intercropping allow diversification in space by growing more than one species in the same field at least for a part of the growing season. This practice may be combined with diversification in time of cash crops as crop rotation including multiservice cover crops and with the use of cultivar mixtures. The interactions and linked processes taking place in species mixtures are complex and occur during the entire growing period. They can be described by the 4C approach composed of Competition, Complementarity, Cooperation, and Compensation effects. We focus on the land equivalent ratio (LER) and the analysis of the partial LER of each species of the mixture to assess the net effect of the 4C effects on the final intercrop performance

THE 4C APPROACH

LAND EQUIVALENT RATIO AND 4C APPROACH TO ASSESS THE PERFORMANCE OF INTERCROPS

COMPENSATION FOR INCREASED YIELD STABILITY IN INTERCROPPING

CONCLUSIONS

Findings

Compliance with ethics guidelines