Improvement of a Mechanical Weeding Technique in a Paddy Field where a Large Number of Monochoria vaginalis and Schoenoplectus juncoides Emerged : Development of a Mechanical Weeding Technique for Intra-row Spaces

Abstract

Rice bran treatment of soil surfaces in paddy fields does not adequately control two weeds, Monochoria vaginalis (Pontederiaceae) and Schoenoplectus juncoides (Cyperaceae). After changing the arrangement of the rotor in a walking culti-vator, we examined the effect of weeding the intra-row spaces on the control of weeds in com-bination with rice bran treatment. In rice paddy fields where many of these residual weeds emerged after rice bran treatment, weeding the intra-row spaces twice reduced not only M. vaginalis and S. juncoides in the row spaces but also S. juncoides in the intra-row space. Compared to the weed-suppressive technique of rice bran treatment alone, the combination of rice bran treatment and weeding the intra-row space twice preserved paddy rice yields by more effectively controlling weeds.