Non-chemical weed management for sustainable rice production in the Ebro Delta

Abstract

Weed control is one of the major challenges in rice cultivation, and the use of agrochemicals in this crop is severely restricted under the new European agricultural policy. Therefore, new effective non-chemical weed control agents are the key to sustain European rice production. We investigated four non-chemical weed management strategies in the Ebro Delta in north-eastern Spain, two in dry-seeded rice fields and two in water-seeded rice fields. In addition, two controls per sowing conditions were included; a positive control consisting in chemical herbicides treatment and a negative control consisting in no weeding and no seeding. In all tests but negative controls, the rice variety Argila was employed. "Simple dry seeding" was the best treatment for dry seeding, while "false seeding" (stale seed bed) and planting was the best performing under water seeding conditions. Both mentioned treatments were as effective as chemical control in reducing the density of weeds and the weeding time for those species more abundant in Ebro Delta rice fields (i.e. Echinochloa oryzoides, Echinochloa crus-galli, Scirpus maritimus and Heteranthera reniformis). Our results indicated that some of the non-chemical weed control methods can reduce weed pressure to levels similar to standard chemical herbicide treatments under certain seeding conditions.