Temporal Differentiation of Crop Growth as One of the Drivers of Intercropping Yield Advantage

Nan Dong,Xing-Guo Bao,Ming-Ming Tang,Wei-Ping Zhang,Yu Wang,Peter Christie,Long Li

doi:10.1038/s41598-018-21414-w

Nan Dong, Xing-Guo Bao + Show 5 more

Open Access

https://doi.org/10.1038/s41598-018-21414-w

Copy DOI

Abstract

Intercropping studies usually focus on yield advantage and interspecific interactions but few quantify temporal niche differentiation and its relationship with intercropping yield advantage. A field experiment conducted in northwest China in 2013 and 2014 examined four intercropping systems (oilseed rape/maize, oilseed rape/soybean, potato/maize, and soybean/potato) and the corresponding monocultures. Total dry matter data collected every 20 d after maize emergence were fitted to logistic models to investigate the temporal dynamics of crop growth and interspecific interactions. All four intercropping systems showed significant yield advantages. Temporal niche complementarity between intercropped species was due to differences in sowing and harvesting dates or the time taken to reach maximum daily growth rate or both. Interspecific interactions between intercropped species amplified temporal niche differentiation as indicated by postponement of the time taken to reach maximum daily growth rate of late-maturing crops (i.e. 21 to 41 days in maize associated with oilseed rape or potato). Growth trajectories of intercropped maize or soybean recovered after the oilseed rape harvest to the same values as in their monoculture on a per plant basis. Amplified niche differentiation between crop species depends on the identity of neighboring species whose relative growth rate is crucial in determining the differentiation.

Highlights

The main advantage of intercropping is the increase in productivity[14,15] by exploiting the full duration of solar radiation[16,17,18], thermal energy[19], water[7,20,21] and nutrient resources[4,22] in resource-limited ecosystems
Our study provides evidence that grain yields, above-ground dry weight and the maximum above-ground dry weights (Ymax) of all intercropped species were approximately equal to or significantly higher than those of the corresponding monocultures (Tables 1, 2)
Similar yield advantages have long been recognized in other intercropping systems[5,24] and a meta-analysis found that the average value of land equivalent ratio (LER) was 1.22 ± 0.0243

Summary

Introduction

The main advantage of intercropping is the increase in productivity[14,15] by exploiting the full duration of solar radiation[16,17,18], thermal energy[19], water[7,20,21] and nutrient resources[4,22] in resource-limited ecosystems. Previous studies show that intercropping advantages depend greatly on niche differentiation in time[12,13] and space[18,22,27,28], or on positive interspecific interactions (facilitation)[17,23] between intercropped species, thereby moderating competition[29]. Plant competition has been studied for many decades but it is usually evaluated as a difference in biomass at a single, arbitrary, stage of growth[30]. Divergences in the biomass trajectories between intercropped and sole-cropped maize may lead to a reliable interpretation[33]. We employ the logistic growth function to analyze the growth trajectories of the interacting species in four intercropping systems with large variation in crop growth traits. Previous studies have mostly investigated individual intercropping systems but few investigations have focused on multiple intercropping within the same study

Objectives

Results

Conclusion