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Conference abstract2014

Weed control effect of covering seed rows of an organic carrot crop with sand, compost or soil

Hansson, David; Svensson, Sven-Erik

Abstract

In a three-year study at Raggården, Västra Götaland, Sweden, the weed control effect of covering the seed rows of an organic carrot crop with sand, compost or soil was examined The first experiment (2009) showed that covering the seed rows with 2 or 4 cm sand, garden compost or dry arable soil as the sole weed control method was not sufficient and had to be complemented with flaming, row hoeing and hand-weeding to produce a satisfactory effect. The second experiment (2010) studied the combined effect of sowing the carrot seed at different depths (2, 3, 4 cm) flaming prior to carrot emergence and soon thereafter covering the seed rows with 0, 1 or 2 cm compost. Sowing at 2 cm depth in combination with 2 cm compost gave the lowest number of weeds (approx. 30 per m²), while sowing at 2 cm depth in combination with 1 cm compost or no compost gave twice as many weeds. Carrot emergence was faster and early postemergence growth greater in the treatments involving covering with compost. Thus the compost layer did not delay carrot emergence. The third experiment (2011) also studied the combined effect of sowing to different depths, flaming prior to carrot emergence and then covering with compost. Sowing at 2 cm depth in combination with 2 cm compost (requiring approx. 40 m3 compost per ha) lowered weed numbers by approx. 60%, but also reduced the number of carrots per row-metre by 30%, compared with no compost covering. The period following application of the dark garden compost was cloudy and rainy in this year, which probably contributed to lower emergence after covering with 2 cm compost. However, final yield remained unaffected at approx. 75 ton hand-harvested carrots per ha.

Published in

Title: Proceedings 10th EWRS Workshop on Physical and Cultural Weed Control
Publisher: European weed research society (EWRS)

Conference

10th EWRS Workshop on Physical and Cultural Weed Control