Read Me for Intercropping Data Documentation

In all files Treatment: OSR is winter oilseed rape, OSR+Sfaba has OSR
intercropped with spring faba, OSR+Clover is OSR intercropped with
clover, OSR+Wfaba is OSR intercropped with winter faba, OSR+Wpeas is OSR
intercropped with winter peas. In some files OSR may say WOSR− in both
cases it refers to winter oilseed rape. Wfaba and Wpea are sole crop
treatments only in FIAdataFinal_FabaRustJuly2020.csv or In
FIAdataFinal_WeedsMayYieldAug2020.csv. All sampling takes place across 4
blocks in a complete random block arrangement with 1 treatment plot per
block replicate. Dates are given as YYYY-MM-DD.

In FIAdataFinal_FabaRustJuly2020.csv the disease severity index as given
for each plot in which faba bean was present. An assessment of faba bean
rust (*Uromyces faba*) were conducted in treatments with winter faba
bean: sole winter faba bean (Wfaba) and OSR+Wfaba. The top ten leaves
were collected from faba bean plants on July 10, 2020 and frozen until
assessment. Leaves were assessed and classed based on the percentage of
infected leaf area as follows: 0=no visible symptoms, 1≤1%; 2=1–5%;
3=6–10%; 4=11–25%; 5=26–50%; 6≥50%; 7=wilted. TreatNum and
PlotID are internal references irrelevant to interpretation of the data.

In FIAdataFinal_March2020CSFBlarva.csv data from March 2, 2020 (BBCH
30–32) CSFB larva were counted in OSR, OSR+Clover and OSR+Sfaba. Forty
randomly selected plants per treatment were collected (10 plants per
plot, assessed plants were at least 1 m from any plot edge). The plants
were dissected in the laboratory and the number of CSFB larvae per OSR
plant were counted. Variables are Date, DateNum, Pesticide (none),
Treatment, Block, PlantNum (individual dissected plant), Diameter(mm) of
the stem in millimeters, NumLeaves (number of leaves on the dissected
plant), 1st_instarTotal,2nd_InstarTotal and 3rd_InstarTotal
indicate the instar stage of any larva found in the plant, SumLarv
indicates the sum of all larva found in the plant. BBCH is the
Biologische Bundesanstalt, Bundessortenamt und Chemical Industry crop
stage.

FIAdataFinal_Sept2019Damage.csv sampled on the 26 September, 2019 and
FIAdataFinal_Nov2019Damage.csv sampled on the 4 November, 2019 both have
the Date, Sample Day relative to the first autumn date of sampling,
Pesticide (None in all treatments), Treatment, Block, Plot (within
block, irrelevant here), Rep is the replicate of 60cm quadrats within
each plot, WOSRDensity and IntercropDensity are the number of OSR and
intercrop plants, respectively, in that 60cm quadrat, CropStageWOSR is
the BBCH crop stage of the OSR, CropStageOther is the BBCH of the
intercrop plant, PlantNum is the replicate ID of plants that were
checked for flea beetle and slug damage (only the first five OSR plants
in the lower left corner of the quadrat were checked for damage). On
each plant SlugDamage and FleaBeetleDamage, respectively, were
separately scored from 0–10 corresponding to 0–100% damage, 100% damage
indicates no remaining leaves.

In FIAdataFinal_PB_BPMdamageJune2020.csv the Date, Location, Ruta (is
the plot ID), Block, Led is a Treatment number ID (irrelevant here),
Treatment has RapsAkerbona=OSR+Sfaba, RapsAlexand=SR+Clover,
RapsHostakerbona=OSR+Wfaba, RapsHostart=OSR+Wpeas, RapsRen=OSR,
Falt and Alt. are alternate PlotID also not relevant, Plant is the plant
number assessed in each plot, PropPollenBeetleDamage and
PercentPollenBeetleDamage are the proportion and percent Pollen Beetle
damage. PropBrassicaPodMidgeDamage and PercentBrassicaPodMidgeDamage are
the proportion and percent damage from Brassica Pod Midge. Damage from
pollen beetles (PB, *Brassicogethe*s spp., primarily *Brassicogethes*
*aeneus*) and brassica pod midge (BPM, *Dasineura brassicae*) were
considered the spring pests of greatest concern. Damage to OSR seed pods
was assessed on June 23, 2020 at approximate crop stage BBCH 80, when
most seed pods were still somewhat green, which facilitated
identification of galls from BPM. In each plot, 10 random OSR plants
were selected across the length of the plot. On each plant, the number
of pods and empty, podless stalks were counted on the top shoot and the
two uppermost side shoots. Number of flower buds destroyed by PB was
considered equal to the number of podless stalks, and damage was
estimated as percentage of podless stalks. Number of pods on each shoot
damaged by BPM was identified through characteristic yellowish, swollen
galls. In uncertain cases, pods were opened to check for the presence of
larvae. Some cases of BPM damage, with already evacuated pods, were
identified through characteristic cracking and splitting of the pod.
Damage by BPM was estimated as the percentage of damaged pods, not
counting empty stalks previously damaged by PB.

In FIAdataFinal_SlugCageDamage.csv Treat is the Treatment, Rep is the
cage replicate per treatment, Index is the cage ID, Day indicates the
7^th^ and final day of the experiment. The columns damageOSR1,
damageOSR2, damageOSR3, damageOSR4, damageOSR5 indicate the proportion
damage from slugs on each of the five OSR plants respectively in each
cage while

damageOther1, damageOther2, damageOther3, damageOther4, damageOther5
indicate the proportion slug damage to each nonOSR plant in the
intercropped cages. ProportionDamageOSRmean and
ProportionDamageOTHERmean are the means slug proportion damage on OSR or
nonOSR per cage across the five plants. To assess the effect of
intercropping on slug preference in a controlled environment, 15 cages
per treatment with five OSR plants per cage were used (BBCH 12–13). The
intercrop treatments included the addition of five spring faba
(OSR+Sfaba) or berseem clover (OSR+Clover) seedlings. Adult slug
specimens of *Deroceras reticulatum* were collected around Uppsala,
Sweden in the autumn of 2019. Slugs were starved for 24 h prior to the
start of the experiment. One slug was placed in each of the 45 cages. On
each OSR plant slug damage was separately scored after seven days for
proportion damage.

In FIAdataFinal_WeedsMayYieldAug2020.csv Treatment, TreatNum, Block
and BlockID (plotID) are given for each plot of each treatments
sampled (OSR,OSR+Sfaba,OSR+Clover,OSR+Wfaba,OSR+Wpea,Wfaba and Wpea),
OSR.g,Legumes.g, WeedsInRow.g, WeedsBtwnRow.g and WeedsTotal.g are
grams of OSR,Legumes, Weeds in the OSR row, weeds between the OSR rows
and total weeds, respectively, in grams. Weed aboveground biomass was
sampled May 19–22, 2020, when the winter OSR crop was in between full
flowering and end of flowering stages (BBCH 65–69) and before most
weeds had set seed. In each plot, weed and crop biomass was collected
by cutting all plants at the soil surface in four 0.25 m2 quadrats
per plot. The quadrats were placed in each corner of the plot
including one OSR row and the entire adjacent inter-row space. The
quadrat was at least 1 m from the edges while avoiding the central 2 x
12 m part of the plot. The collected plants were sorted into: OSR; the
sown legume species (if any); and weeds. All plants per sorted
fraction were pooled from the four quadrats, dried at 80 °C for at
least 24 h (until stable weight) and weighed. Total weed biomass, OSR
and legume biomass (dry weight per area unit in all cases) were
recorded. OSRYield.kgPERha, LegumeYield.kgPERha are the wet weight
yield in kilograms per hectar for OSR and the respective legumes.
OSRYield.kgPERhaDRY and LegumeYield.kgPERhaDRY are the dry weights.
The experiment was harvested on August 4, 2020 when OSR, winter faba
bean and winter peas were mature. Total grain yield was measured by an
experimental combine harvester, which collected all harvestable grains
from a previously undisturbed central 2m-wide strip in each plot (24
m2). A sub-sample of the harvested grains from each plot (approx. 1
kg) was dried at 80 °C for at least 24 h (until stable weight)
before manual sorting of OSR, winter faba bean and winter pea seeds.
Grain and legume yields (kg/ha, dry weight) were calculated based on
proportional subsample weight.