Crop establishment and grain yield of direct sowing culture of rice [Oryza sativa] with recycled-paper mulch

The direct sowing culture of rice with recycled-paper mulch is practiced by spreading recycled paper (to which rice seeds are attached) on the surface of puddled soil. This cultural practice would eliminate the application of herbicides. Furthermore, it is labor saving in comparison with transplanting. This study objects to characterizing the crop establishment, lodging occurrence, and weed infestation in direct sowing with recycled-paper mulch (hill and drill sowing) in comparison with broadcast direct sowing and transplanting. Broadcast direct sowing was practiced with or without seed-coating with oxygen release chemical (major ingredient calcium peroxide). Transplanting was done with and without use of recycled-paper mulch. Cultivars Koshihikari, a popular high-grain quality rice susceptible to lodging, and Dontokoi, a high-grain quality with resistance to lodging, were used. Herbicides were applied for broadcast sowing and transplanting where no recycled-paper mulch was used. Five experiments were conducted during 1997 and 1998, and we used netting to protect the seeds and seedlings from bird attack. The crop establishment was better in the following order: direct sowing with recycled-paper mulch (hill), broadcast sowing with coated seeds, and broadcast sowing with noncoated seeds. The crop establishment in direct sowing with recycled-paper mulch (drill) was similar to that in broadcast sowing with noncoated seeds. The lodging occurred less in the following order: transplanting, direct sowing with recycled-paper mulch (hill) , and direct sowing with recycled-paper mulch (drill) We detected no significant difference in weed infestation between the cultural methods employed in the present study. No herbicide application and hand weeding would be required in direct sowing with recycled-paper mulch (hill and drill). The grain yield of direct sowing with recycled-paper mulch was as much as, or a little less than, that of transplanting.