Punch planting, flame weeding and delayed sowing to reduce intra-row weeds in row crops

Abstract

Punch planting has recently been suggested as a technique to reduce intra-row weeds in organically grown row crops. The technique is to punch holes in the ground and seeds are then inserted, with a minimum of soil disturbance outside the hole. Two series of experiments with a tractor-mounted prototype of a dibber drill (MK III) are presented. In the first series, three crop establishment procedures were compared over 2years at five different sowing dates in sugar beet and direct-sown onion. The crop establishment procedures were as follows: (i) normal sowing and mechanical control of weeds in the stale seedbed (N), (ii) N+pre-emergence flame weeding (N+F) and (iii) punch planting and flame weeding to control weeds in the seedbed prior to crop emergence (P+F). The difference between N and N+F treatments quantifies the effect of pre-emergence flame weeding, and the difference between N+F and P+F quantifies the effect of punch planting. Punch planting reduced the average intra-row weed density by 37% in onion but had no main effect in sugar beet. In the second series of experiments in carrot, which compared the N+F and the P+F treatments only, punch planting reduced the average intra-row weed density by 34%. Pre-emergence flame weeding reduced the average weed density by 59% in onion and by 47% in sugar beet. Delayed sowing without pre-emergence flame weeding only reduced weed emergence in 1 of 2years, whereas delayed sowing had a more pronounced effect in flame-weeded (N+F) and punch-planted plots (P+F). In sugar beet and onion, there were complex interactions between crop establishment procedure, year and delayed sowing, which are partly explained by weather conditions and species-specific germination patterns. It was concluded that technical improvements to the dibber drill (MK III) are required to take advantage of punch planting to reduce intra-row weed densities. © 2011 The Authors. Weed Research © 2011 European Weed Research Society.