Title: Evaluation of thermal implements and organic herbicides for weed control in a non-bearing almond (Prunus dulcis) orchard

Abstract: Sustainable weed management strategies are needed for organic orchard systems. A study was conducted in an almond orchard in Fresno, CA from 2009 to 2011. Treatment comparisons included steam, flame, and broad applications of either lemongrass oil or d-limonene. An untreated control was also included. The experimental design was a randomized complete block with four replications. Weekly evaluations on percent weed control were taken and weed biomass was sampled 4 to 8 weeks after treatment (WAT). Weed control and biomass differed between seasons but, in general, steam and flame provided as much as 95% control 1 WAT. However, the effects lasted only 3 to 4 wk as new weeds emerged or the treated weeds overcame the suppressive effects of the thermal treatments. Weed biomass was 95% lower in the steam and flame treated plots compared to the untreated plots in summer. Both steam and flame were more effective on certain erect-growing broadleaved weed species than on prostrate growing weeds and grasses. Lemongrass oil provided very little weed control. However, d-limonene provided up to 95% weed control 1 WAT and in one experiment 53% control was observed up to 5 WAT. This herbicide also resulted in lower weed biomass than the untreated and the thermal treated plots. Monthly applications of steam or flame or applications of d-limonene every 5-6 wk may have to be made to adequately suppress weeds in an organic almond orchard. Cost estimates of propane use were $41 to 56 ha-1 and $26 ha-1 for the steam and flame treatments, respectively. The cost of d-limonene was estimated as $275 ha-1. To optimize weed control and costs, these tools should be used in combination rather than by themselves. [Anil Shrestha, Marcelo Moretti, and Nathalia Mourad (2011). Evaluation of thermal implements and organic herbicides for weed control in a non-bearing almond (Prunus dulcis) orchard. Weed Technology, on-line Nov. 18, doi: 10.1614/WT-D-11-00083.1]

Keywords: Organic weed control, steam, propane flaming, lemongrass oil, d-limonene, Greenmatch.

Original source



Article: WeedsNews2547 (permalink)
Categories: :WeedsNews:research alert, :WeedsNews:organic farming, :WeedsNews:weed control, :WeedsNews:orchard weeds
Date: 19 November 2011; 3:52:10 pm Australian Eastern Daylight Time

Author Name: David Low
Author ID: adminDavid