1 Economic Aspects of Physical Intra-Row Weed Control in Seeded Onions

Hand weeding is still widely used in Northern Europe as the primary method for controlling weeds growing between the crop plants in the row (intra-row) in organic vegetables, such as seeded onions and leek, and carrots. Weeds between the crop rows (inter-row) can normally be controlled satisfactorily by inter-row cultivations. Danish and Swedish vegetable growers commonly spend 100-300 h ha-1 to hand-weed onions and carrots (Ascard, 1990; Nielsen and Larsen, 1991), but the time may reach 500 h ha-1 in particularly weedy situations (Melander, un-published). This is an appreciable financial burden in organic vegetable growing. Therefore, research has been conducted in recent years looking for effective physical intra-row weed control methods. New results have shown that combining pre-emergence flaming with post-emergence brush weeding can control more than 80 % of intra-row weeds in seeded onions and kale without significantly damaging the crop (Melander, 1998). However, such a strategy is based on the use of special and expensive machinery. To the grower, this means considerable machinery investments. The objective of this paper is to compare the economics of physical intra-row weeding and pure hand-weeding, exemplified respectively by two weed manage-ment systems for seeded onions grown in single rows with 50 cm row spacing. Materials and Methods Weed management systems considered In the first system (S1), intra-row weed control uses only hand weeding, while inter-row weeding is based on conventional hoeing with no extra need for manual weed removal