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Data from: The interplay of intercropping, wildflower strips and weeds in conservation biological control and productivity

Cite this dataset

Hatt, Séverin; Döring, Thomas F. (2024). Data from: The interplay of intercropping, wildflower strips and weeds in conservation biological control and productivity [Dataset]. Dryad. https://doi.org/10.5061/dryad.w6m905qxm

Abstract

Diversifying agroecosystems is instrumental to reduce pesticide use in agriculture. While different diversification practices have the potential to reduce pests, their integration at the agroecosystem level and the evaluation of their multifunctional effects remain limited. Through a two-year field experiment conducted in Germany, we tested whether associating intercropping (faba bean-wheat, followed by breadseed poppy-barley) with pluriannual wildflower strips strengthens the biological regulation of aphid pests and weeds, and enhances cropping system productivity. The contribution of flowering weeds to conservation biological control was also analysed. Aphid colonization rates, but also predator colonization and predation rates, on bean and poppy were consistently lower in intercropping compared to sole cropping. Associating wildflower strips to intercropping enhanced aphid predation in bean-wheat intercropping, and further reduced aphid colonization at 10 m distance from the flower strip but not at 20 m in poppy-barley intercropping. Weed biomass was strongly reduced in intercropping compared to sole crop bean and poppy, and did not significantly affect bean and poppy yields in intercropping. The cover of one flowering weed species, Matricaria recutita, was negatively correlated to aphid colonization rate and positively correlated to predation rate in bean-wheat intercropping. In poppy-barley intercropping, M. recutita flowers were visited more often by predatory hoverflies in plots adjacent to wildflower strips. Finally, land equivalent ratio, measuring land-use efficiency, was consistently higher than 1, and the highest in bean-wheat intercropping associated to wildflower strips. The study shows that intercropping is key to control multiple pests and enhance land-use efficiency, and demonstrates that associating wildflower strips to intercropping can strengthen biological control and cropping system productivity. Flowering weeds, maintained at an acceptable level through intercropping, turn out to be relevant functional biodiversity in interacting with wildflower strips to support natural enemies for conservation biological control.

README: The interplay of intercropping, wildflower strips and weeds in conservation biological control and productivity

https://doi.org/10.5061/dryad.w6m905qxm

The data are retrieved from a field experiment conducted in Germany (50°47’14N, 7°16’38E; city: Hennef) in organic farming conditions during the years 2020-2022.

The experiment tested whether increasing crop diversity (sole cropping vs. intercropping) and field margin management (wildflower strip vs. crop strip) affects:

  • Aphid infestation and predator colonization rate: Hatt_and_Doering_2024_aphid_and_predator_rates.csv
  • Predation rate of aphids by predators: Hatt_and_Doering_2024_predation_rates.csv
  • Weed biomass at harvest: Hatt_and_Doering_2024_weed_biomass.csv
  • Crop yield: Hatt_and_Doering_2024_grain_yield_crop.csv

In addition in the intercropping systems, the experiment analysed the relationship between weed flowers and insects with the following datasets:

  • Abundance of flowering weeds:
    • Hatt_and_Doering_2024_blooming_weeds_2021.csv
    • Hatt_and_Doering_2024_blooming_weed_flower_area_2021.csv
    • Hatt_and_Doering_2024_blooming_weeds_2022.csv
    • Hatt_and_Doering_2024_insect_weed_flower_interactions_2022.csv

Studied crops were faba bean (Vicia faba) and wheat (Triticum aestivum) in 2020-2021, and breadseed poppy (Papaver somniferum) and barley (Hordeum vulgare) in 2022.

All data were collected in quadrats (1m2 surface). One quadrat is always defined by the type of “Margin” (flower vs. control), “Cropping_system” (intercropping, sole cropping) and “Distance_(m)” (10 vs. 20, sometimes also 10_weed_free) and the experiment “Block” (1 to 4).

Description of the data and file structure

Hatt_and_Doering_2024_aphid_and_predator_rates.csv – Aphid infestation rate (“Aphid_rate”) and predator colonization rate (“Predator_rate”) per quadrat on faba bean (2021, 2 samplings) and breadseed poppy (2022, 1 sampling) in sole cropping and in intercropping. Values are rates, comprised between 0 and 1.

Hatt_and_Doering_2024_predation_rates.csv – Predation rate (“Predation_rate”) evaluated by using two predation cards (“Card_no”) per quadrat on faba bean (2021, 2 samplings) and breadseed poppy (2022, 1 sampling) in sole cropping and in intercropping. Values are rates (number of aphids preyed divided by five aphids originally glued), comprised between 0 and 1.

Hatt_and_Doering_2024_weed_biomass.csv – Biomass of weeds (“Weed_biomass_(g)”) harvested at crop harvest in each quadrat (intercropping and the two sole cropping) in 2021 and 2022. They are absolute values in grams.

Hatt_and_Doering_2024_grain_yield_crop.csv – Grain yield (“Grain_yield_(g)”) of faba bean (2021) and breadseed poppy (2022) in each quadrat (intercropping and the two sole cropping, including also the weed-free quadrats in intercropping). They are absolute values in grams. Grain yield was used also to calculate land-equivalent ratios, and the relative difference of yield between regular and weed-free quadrats in intercropping (at 10 m).

Hatt_and_Doering_2024_blooming_weeds_2021.csv – Abundance of weed species flowering found in the intercropping quadrats monitored over five samplings in 2021 (4 May, 19 May, 7 June, 25 June and 13 July 2021). Values are the number of inflorescences for Matricaria recutita and Papaver rhoes, or the number of individual plants for all the other species/genus.

Hatt_and_Doering_2024_blooming_weed_flower_area_2021.csv – Area of weed flowers for the species found in the intercropping quadrats in 2021. Area values are in cm2. Inflorescence areas are given either at the scale of the individual plant (“Average_flower_area_per_plant_cm2”), or at the scale of the inflorescence (“Average_area_per_flower_cm2”, for Matricaria recutita and Papaver rhoeas).

Hatt_and_Doering_2024_blooming_weeds_2022.csv – Abundance weed species (“Plant_species”) flowering found in quadrats (intercropping only) monitored on 4 July 2022. These data are to be related with the observations of insect-flower visitations done on the same day. Values are the number of inflorescences (“Inflorescence_abundance”).

Hatt_and_Doering_2024_insect_weed_flower_interactions_2022.csv – Number of visitations of weed flowers by insects (“Insect_taxa”) in quadrats (intercropping only) monitored on 4 July 2022. Each line represents one insect individual (“Insect_no”), and the values per plant species represents the number of contacts by this insect. Hence, the data allows calculating both the number of insects observed by taxa, and the number of insect-flower interactions.

Methods

The data are retrieved from a field experiment conducted in Germany (50°47’14N, 7°16’38E; city: Hennef) in organic farming conditions during the years 2020-2022.

The experiment tested whether increasing crop diversity (sole cropping vs. intercropping) and field margin management (wildflower strip vs. crop strip) affects biological control of insect pests (aphids), weed biomass and productivity (crop yield, land-equivalent ratio). In addition in the intercropping systems, the experiment analysed the relationship between weed flowers and insects towards biological control.

Studied crops were faba bean (Vicia faba) and wheat (Triticum aestivum) in 2020-2021, and breadseed poppy (Papaver somniferum) and barley (Hordeum vulgare) in 2022.

All data were collected in quadrats (1m2 surface). One quadrat is always defined by the type of “Margin” (flower vs. control), “Cropping_system” (intercropping, sole cropping) and “Distance_(m)” (10 vs. 20, sometimes also 10_weed_free) and the experiment “Block” (1 to 4).

For more information, please refer to the Material and Methods of the published article.

Funding

European Commission, Award: 891566, Marie Skolodowska-Curie Individual Fellowship