Grain Yield Stability of Cereal-Legume Intercrops Is Greater Than Sole Crops in More Productive Conditions

The intercropping of two or more crop species on the same piece of land at a given time has been hypothesized to enhance crop yield stability. To address this hypothesis, we assessed the grain yield stability of various barley-pea and wheat-faba bean mixtures grown in seven experimental field trials (locations) across Europe during two years with contrasting weather (2017 and 2018). Three different yield stability measures were used, all based on the expected yield variability of the mixture components grown as sole crops, and the corresponding observed yield variability of the same components grown in 50:50 mixtures in a replacement design. Stability indices were calculated as ratios between the expected and observed variabilities, with values > 1 indicating greater stability of the intercrops. Mean grain yields tended to be higher in intercrops than sole crops. However, in contrast to our hypothesis, the observed (intercrop) yield stability was similar or lower than the expected (sole crop) stability in most locations except one. Furthermore, yield stability significantly increased with increasing mean yields when assessed across differentially productive locations. The results are relevant for the designing of intercropping systems as a means to increase yield stability and the resilience of cropping systems.This research was funded by the DIVERSify project, a grant from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 727284. MR was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—420661662. A.J.K. and A.C.N. are also supported by the strategic research programme funded by the Scottish Government’s Rural and Environment Science and Analytical Services Division.Peer reviewe

Multispecies crop mixtures increase insect biodiversity in an intercropping experiment

Abstract Recent biodiversity declines require action across sectors such as agriculture. The situation is particularly acute for arthropods, a species‐rich taxon providing important ecosystem services. To counteract the negative consequences of agricultural intensification, creating a less hostile agricultural ‘matrix’ through growing crop mixtures can reduce harm for arthropods without yield losses. While grassland biodiversity experiments showed positive plant biodiversity effects on arthropods, experiments manipulating crop diversity and agrochemical input used to study arthropods are lacking. Here, we experimentally manipulated crop diversity (1–3 species, fallows), crop species (wheat, faba bean, linseed and oilseed rape) and agrochemical input (high vs. low) and studied responses of arthropod biodiversity. We tested whether arthropod responses were affected by crop diversity, mixtures and management. Additionally, we measured crop biomass. Crop biomass increased with crop diversity under high‐input management, while under low management intensity, biomass was highest in two‐species mixtures. Increasing crop diversity positively affected arthropod abundance and diversity, under both low‐ and high‐input management. Crop mixtures containing faba bean, linseed or oilseed rape had particularly high arthropod diversity. Mass‐flowering crops attracted more arthropods than legumes or cereals. Integrating intercropping into agricultural systems could increase flower visits by insects up to 1.5 million per hectare, thus likely also supporting pollination and pest‐control ecosystem services. Flower visitor network complexity increased in mixtures containing linseed and faba bean and under low‐input management. Intercropping can counteract insect declines in farmland by creating beneficial matrix habitat without compromising crop yield

Antagonistis responses to crop diversification at two levels of fertiliser and herbicide application

The use of pesticides and fertilisers in the last decades has led to numerous problems for mankind and the environment: polluted ground water, decreased soil quality, biodiversity loss and resistance of weed and pest species. To counteract these problems, conventional farming systems will need to become more sustainable. One approach is intercropping, which is common in traditional or low intensity farming, but not in conventional agriculture. Thus, little is known about responses of biotic interactions to intercropping under conventional management. In a cereal-legume intercropping experiment, we found that disease infection was highest in cereal sole crops and weed biomass was highest in legume sole crops, while herbivory was highest in intercrops. Management intensity had significant effects on pathogen infection, herbivory and weed biomass, but results differed between wheat-bean vs barley-pea cropping systems, showing that intercropping in conventional agriculture can reduce antagonistic patterns, but also that plant species must be specifically chosen for optimised performance with respect to reduced external inputs

Intercropping in high input agriculture supports arthropod diversity without risking significant yield losses

This study shows effects of intercropping in high and low input agriculture on abundance and diversity of arthropod functional groups and yield. It was conducted as part of the project DIVERSify ('Designing innovative plant teams for ecosystem resilience and agricultural sustainability')

Grain Yield Stability of Cereal-Legume Intercrops Is Greater Than Sole Crops in More Productive Conditions

The intercropping of two or more crop species on the same piece of land at a given time has been hypothesized to enhance crop yield stability. To address this hypothesis, we assessed the grain yield stability of various barley-pea and wheat-faba bean mixtures grown in seven experimental field trials (locations) across Europe during two years with contrasting weather (2017 and 2018). Three different yield stability measures were used, all based on the expected yield variability of the mixture components grown as sole crops, and the corresponding observed yield variability of the same components grown in 50:50 mixtures in a replacement design. Stability indices were calculated as ratios between the expected and observed variabilities, with values > 1 indicating greater stability of the intercrops. Mean grain yields tended to be higher in intercrops than sole crops. However, in contrast to our hypothesis, the observed (intercrop) yield stability was similar or lower than the expected (sole crop) stability in most locations except one. Furthermore, yield stability significantly increased with increasing mean yields when assessed across differentially productive locations. The results are relevant for the designing of intercropping systems as a means to increase yield stability and the resilience of cropping systems