Pest regulation: Use crop rotations
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
Supporting evidence from individual studies
A replicated, randomized, controlled study in 1994–1998 on an irrigated, arable farm near Davis, California, USA, found similar amounts of weed biomass in plots with four-year or two-year crop rotations. Implementation options: Similar amounts of weed biomass were found in plots with four-year or two-year crop rotations (4–273 vs 140–467 kg dry weight/ha). Methods: A four-year rotation (tomato, safflower, corn and wheat, beans) was used on 16 plots (four plots for each phase, each year), and a two-year rotation (tomato, wheat) was used on eight plots (four plots for each phase, each year). Each plot was 68 x 18 m. Fertilizer and pesticide were used on all plots. Weeds were sampled in the tomato plots, at harvest, in 1994–1998.Study and other actions tested
Referenced paperPoudel D.D., Horwath W.R., Lanini W.T., Temple S.R. & van B.A.H.C. (2002) Comparison of soil N availability and leaching potential, crop yields and weeds in organic, low-input and conventional farming systems in northern California. Agriculture, Ecosystems & Environment, 90, 125-137.
A replicated, randomized, controlled study in 2010–2011 in a rainfed field in Western Australia found less weed biomass in plots with a canola-wheat sequence, compared to a wheat-wheat sequence. Pest numbers: Less weed biomass was found in plots with a canola-wheat sequence, compared to a wheat-wheat sequence (36 vs 43 g/m2). Methods: Wheat or canola was grown on three plots each in 2010, and wheat was grown on all plots in 2011. Each plot was 1.4 x 40 m. Fertilizer (150 kg/ha/year) and herbicide were used on all plots. Weeds were sampled at the end of 2011.Study and other actions tested