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Providing evidence to improve practice

Individual study: Cover-Crop Systems Affect Weed Communities in a California Vineyard

Published source details

Baumgartner K., Steenwerth K.L. & Veilleux L. (2008) Cover-Crop Systems Affect Weed Communities in a California Vineyard. Weed Science, 56, 596-605


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Soil: Plant or maintain ground cover in orchards or vineyards Mediterranean Farmland

A replicated, randomized, controlled study in 2002–2005 in an irrigated vineyard in the Napa Valley, California, USA, found similar amounts of organic matter and nutrients in soils with seeded cover crops or resident vegetation. Implementation options: Similar amounts of organic carbon were found in soils with seeded cover crops or resident vegetation (21–24 mg organic matter/g dry soil). Similar amounts of nitrogen (1.6–1.8 mg total N/g dry soil), phosphorus (17–22 µg Olsen P/g dry soil), and potassium (7.3–7.7 µmol exchangeable K/g dry soil) were found in soils with seeded cover crops or resident vegetation. Methods: No tillage or conventional tillage was used on eight plots each, between the vine rows (three vine rows/plot). A disk plough was used for conventional tillage (15 cm depth, once/year in April–June). Four plots with conventional tillage had annual cover crops (seeded in October 2002–2004) and four plots had no seeded cover crops. Four plots with no tillage had annual cover crops (seeded in October 2002–2004), and four had perennial cover crops (seeded in October 2002). All plots were drip irrigated in July–October (85 kl/ha/week). Soil samples were collected under grape vines and between the rows (0–15 cm depth, 4.6 cm diameter, four samples/plot in each location).

 

Crop production: Plant or maintain ground cover in orchards or vineyards Mediterranean Farmland

A replicated, randomized, controlled study in 2002–2005 in an irrigated vineyard in the Napa Valley, California, USA, found similar grape yields in vine rows with ground cover, with or without tillage. Implementation options: Similar grape yields were found in vine rows with ground cover (either seeded cover crops or resident vegetation), with or without tillage (4.3–6.6 kg/vine). Methods: No tillage or conventional tillage was used on eight plots each, between the vine rows (three vine rows/plot). A disk plough was used for conventional tillage (15 cm depth, once/year in April–June). Four plots with conventional tillage had annual cover crops (seeded in October 2002–2004) and four plots had resident vegetation. Four plots with no tillage had annual cover crops (seeded in October 2002–2004), and four had perennial cover crops (seeded in October 2002). All plots were drip irrigated in July–October (85 kl/ha/week). Grapes were harvested from 18 vines/plot (September 2003–2004 and October 2005).

Pest regulation: Plant or maintain ground cover in orchards or vineyards Mediterranean Farmland

A replicated, randomized, controlled study in 2002–2005 in an irrigated vineyard in the Napa Valley, California, USA, found similar numbers of weeds under grape vines, but more weeds between vine rows, in vine rows with seeded cover crops, compared to resident vegetation. Plant diversity between the vine rows decreased over time without tillage, but increased over time with conventional tillage. Tillage had inconsistent effects on plant biomass between the vine rows. Implementation options: Similar numbers of weeds were found under the vines in rows with or without seeded cover crops (2–32 g weed biomass/m2). More weeds were found in interrows with seeded cover crops, compared to interrows with resident vegetation, in three of nine comparisons (cover crops with no tillage: 22–158 vs 1–2 g weed biomass/m2). Plant diversity between the vine rows decreased over time in rows with no tillage, and increased over time in rows with conventional tillage (data reported as the Shannon index), but similar numbers of species were found (3–6 species). Less plant biomass was found between vine rows, in rows with no tillage, compared to conventional tillage, for two plant species (Sonchus aster spiny sowthistle: 0.03–0.09% vs 2.69–2.76% of weed biomass/sample; Anagallis arvensis scarlet pimpernel: 0–0.05% vs 0.12–2.65%), but more biomass was found for one species (Medicago polymorpha California burclover: 2–25% vs 4–8%), and inconsistent biomass was found for three species. Methods: No tillage or conventional tillage was used on eight plots each, between the vine rows (three vine rows/plot). A disk plough was used for conventional tillage (15 cm depth, once/year in April–June). Four plots with conventional tillage had annual cover crops (seeded in October 2002–2004) and four plots had resident vegetation. Four plots with no tillage had annual cover crops (seeded in October 2002–2004), and four had perennial cover crops (seeded in October 2002). All plots were drip irrigated in July–October (85 kl/ha/week). Weeds were sampled under the vines and between the rows (four quadrats/plot in each location, 25 x 40 cm quadrats), when the vines were in full bloom (June 2003, May 2004, and May 2005). Herbicide was used under the vine rows (Glyphosate, twice/year), but not between the rows.