Data from: Integrated Weed Management in Cucurbit Production Using Spring-seeded Grass Cover Crops

Study locations
o Watermelon- University of Maryland Wye Research and Education Center Queenstown, MD (38.9°N, 76.2°W)

o Cucumber- Rutgers Agricultural Research and Extension Center, Bridgeton, NJ (39.5°N,75.2°W)·

Study design: split-split plot arranged on a randomized complete block design with 4 replicates
o Whole plots = post-transplant treatments (clethodim [ 140 g ai·ha^-11], paraquat [ 336 g ai·ha^-1], crimped [no herbicide])

o Subplots = cover crop species (cereal rye [268 kg·ha^-1], oat [310 kg·ha^-1], cereal rye [134 kg·ha^-1] + oat [155 kg·ha^-1], no cover)
o Sub-subplot = residual herbicide (fomesafen [421 g ai·ha^-1] + S-metolachlor [1783 g ai·ha^-1])

Plot size = 4 rows of plastic mulch 7.6 m long, 6.9 m wide in 2021 and 4.6 m long, 6.9 m wide in 2022.

Study dates: 4/21 – 9/21, 4/22/ - 8/22

o Bed formation = MD (4/20/21, 4/14/22), NJ (4/6/21, 4/13/22)
o Cover crop seeding = MD (4/27/21), 4/25/22), NJ (4/7/21, 4/20/22)

o Crop seeding/transplant = MD (6/24/21, 6/16/22), NJ (6/2/21, 6/7/22)
o Post-transplant treatment = MD (7/14/21, 7/12/22), NJ (6/24/21, 7/6/22)

o Harvest = MD (9/8/21-9/21/21, 8/7/22), NJ (7/14/21-8/3/21, 7/26/22-8/9/22)

Data collection
o Cover crop biomass collected from two-0.25m² quadrats randomly selected within each plot
o Smooth pigweed (artificially seeded) density (1 permanent-0.25 m² quadrat placed in the center of each plot) collected prior to post-transplant treatment, 2 weeks after post-transplant treatment.

o Other annual broadleaf weeds (natural population) density (1 permanent-0.25 m² quadrat placed in the center of each plot) collected prior to post-transplant treatment, 2 weeks after post-transplant treatment.
o Smooth pigweed (AMACH) and other annual weed biomass (GEN) collected 6 weeks after post-transplant treatment by cutting all the plants at ground level from the same aforementioned squares. Weed and cover crop biomass samples were benched dried in a greenhouse for 14 d at 35 °C in Maryland, and were or oven-dried at 60 °C for 7 d in New Jersey before weighing.

o Broadleaf (BLD) weed control (relative to the no cover, crimped, no herbicide treatment) in the center (Ctr) of each row and adjacent to the plastic mulch (Edg) was visually evaluated 3 weeks after post-transplant treatments both years in MD and in 2021 in NJ using a 0 to 100 scale, with 0 = no plant response and 100 = complete plant death.
o Harvest
· Individual fruits were harvested from the two center rows within each plot.

· Yield data for both crops consisted of count and weight of total and marketable fruits as well as the individual weight of marketable fruits.

Data analysis
o Data were subjected to analysis of variance (ANOVA) using the generalized linear mixed model (GLIMMIX) procedure in SAS

o Fixed effects = Cover crops, post-plant treatments and inclusion of a residual herbicide as well as all interactions between these three factors.
o Random effects = Locations, runs, and replication nested within runs

o Data transformation = percentage or numerical data were converted using the arcsine square root or the square root transformation, respectively, prior to ANOVA
o Means separation = Tukey’s honest significance test (HSD) test (α = 0.05)

Data files
o MD_Watermelon yield data.csv

o NJ_Cucumber yield data.csv
o NJ+MD cover crop data.csv

o NJ+MD Weed control data.csv
o NJ+MD Weed count pre-term data.csv

o Weed biomass.csv
o Weed contro_at harvest.csv

o Weed count_12 d after term data.csv
o Weed count_41 DATrplt.csv