Abstract: Aimed to understand the effects of various labor-saving rice cultivation modes on the diversity of potential weed communities in paddy fields, an inv
estigation was made on the quantitative characteristics of the weed seed bank under dry direct seeding, water direct seeding, seedling throwing, mechanized-transplanting, wheat-rice interplanting, and conventional manual transplanting. Under dry direct seeding, the density of the weed seed bank was up to 228416 seeds·m^-2, being significantly higher than that under the other five cultivation modes. Wheat-rice interplanting ranked the second place. The seed density of sedge weeds under dry direct seeding and that of broad leaf weeds under wheat-rice interplanting were significantly higher than the seed densities of various kinds of weeds under other cultivation modes. Conventional manual transplanting mode had the highest species richness, with Margalef index being 1.86. The diversity indices, including Shannon-Wiener index, Gini index, and Pielou evenness
index under water direct seeding and wheatrice interplanting were higher than those under other cultivation modes. Comparing with conventional manual transpla
nting mode, the other five cultivation modes had their own dominant species in t
he potential weed community, and thereby, different laborsaving rice cultivati
on modes should be applied by turns to control the potential weed community in p
addy fields effectively and persistently.

Key words: labor-saving cultivation, potential weed community, paddy field, species diversity, seed bank, ginger, drought stress, strong light stress, reactive oxygen, antioxidant enzyme.