Use of Ground Cover Plants in Rice Paddy Levee Management in Tochigi Prefecture, Japan.

—Selection of Suitable Ground Cover for Levee Management—

Abstract

We conducted a trial using ground cover plants as a labor-saving method for managing levees between rice paddies in Tochigi Prefecture, Japan. The four ground cover species tested were phlox (Phlox subulate L.), frogfruit (Lippia nodiflora), centipede grass (Eremochloa ophiuroides), and pennyroyal (Mentha pulegium). Seedlings were prepared, planted on a levee between rice paddies, and continuously monitored for 2 years. After field planting, the growth, change in ground coverage, regrowth after overwintering, and weed suppression of the four ground cover species were compared to identify ground cover plants suitable for levee management. Frogfruit and pennyroyal, which exhibited the fastest growth in the first year after field planting, also reached full coverage in the shortest amount of time and showed superior weed suppression compared with the two other species. In the second year after overwintering, centipede grass, which grew slowly in the first year, exhibited fast growth, rapid coverage, and superior weed suppression similar to frogfruit.