Conservation Evidence: Evidence Data

Collected Evidence: Collected Evidence: Incorporate plant remains into the soil that produce weed-controlling chemicalsWeeds: Six studies (including six randomised, replicated, controlled tests) from Asia, Europe and North America examined the effect of allelopathic plant remains on weeds by comparing amended soils with weeded controls. Three studies found a reduction in weed growth, and three found effects varied between years, weed groups, or the type of weeding method in controls.Four studies from Asia and North America examined the effect on weeds by comparing amended soils with unweeded controls. Two studies found a reduction in weed growth, but one found that residues applied too far in advance of crop planting had the reverse effect. Two studies found that effects varied between trials, weed species or the type of residue used.Two studies, including one randomised, replicated, controlled laboratory study, found that the decrease in weeds did not last beyond a few days or weeks after residue incorporation. Pests: One randomised, replicated, controlled study in the Philippines found mixed effects on pests. Crop growth: Two of three studies found crop growth was inhibited by allelopathic plant remains, but this could be minimised by changing the timing of application. One study found effects varied between years. Yield: Three randomised, replicated, controlled studies compared yields in amended plots with weeded controls and found positive, negative and mixed effects. Three studies compared amended plots with unweeded controls, two found positive effects on yield and one found mixed effects (depending on the crop). Profit: One study found that amending soils increased profit compared to unweeded controls, but not compared to weeded controls. Crops studied were beans, cotton, maize, rice and wheat.Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F728https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F728Thu, 30 May 2013 13:50:22 +0100