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Providing evidence to improve practice

Individual study: Effect of Seeding Rate and Planting Arrangement on Rye Cover Crop and Weed Growth

Published source details

Boyd N.S., Brennan E.B., Smith R.F. & Yokota R. (2009) Effect of Seeding Rate and Planting Arrangement on Rye Cover Crop and Weed Growth. Agronomy Journal, 101, 47-51


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Pest regulation: Grow cover crops in arable fields Mediterranean Farmland

A replicated, randomized, controlled study in 2003–2005 on an irrigated vegetable farm in Salinas, California, USA (partly the same study as (12)), found fewer weeds in plots that were sown with more cover crop seeds, compared to fewer, and in plots that were planted in a grid of perpendicular rows, compared to parallel rows. Implementation options: Fewer weeds were found in plots that were sown with more cover crop seeds, in five of six harvests (270 kg seeds/ha: 0–10 kg weeds/ha; 180 kg seeds/ha: 1–22 kg weeds/ha; 90 kg seeds/ha: 6–47 weeds/ha). Fewer weeds were found in plots that were sown in a grid (two passes of the seed drill, in perpendicular rows, with half as many seeds/pass as conventional passes), compared to conventionally (one pass, in parallel rows), in one of six harvests (1 vs 6 kg weeds/ha). Weeds emerged at similar times in plots planted with different amounts of seed, and in plots planted in a grid or conventionally (data not reported). Methods: Twenty-four plots were planted with winter cover crops (Secale cereale Merced rye), with 90, 180, or 270 kg seeds/ha, in October 2003–2004 (12 x 12 m plots). Half of these plots were planted in grid, and half were planted conventionally. Weed biomass was measured 18 days after planting (two quadrats/plot, 50 x 50 cm quadrats).