放牧利用年数の異なる水田転換草地の埋土種子相

概要

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This study investigated buried seeds in pastures converted from paddy fields and grazed for various grazing years with cattle : Pastures T1 (grazed at the first year from the conversion), T2 (at the second year), N3 (at the third year) and N8 (at the eighth year), so as to predict the extent of weed damage in rice when the converted pastures were reconverted again to paddy field. Buried seed species were found at 15, 18, 21 and 29 species in pastures T1, T2, N3 and N8, respectively, and paddy field weed species were at 9, 8, 11 and 11 in each of pastures. The number of buried seed of paddy field weeds was the largest in pasture T2 (5,640 seeds/m^2 in the 0 to 10cm layer), followed by pastures T1 (2,534), N3 (2,394) and N8 (2,012). The numbers of buried seed of non-paddy-field weeds and of whole weed communities were larger in pasture N8 than in pastures T1, T2 and N3. In all the pastures, the number of seed of non-paddy-field weeds was larger than those of paddy field weeds and sown herbage. From the results, we concluded that the risk of weed damage would not always decrease as increase of grazing years when pastures converted from paddy fields are reconverted to paddy field again.
日本草地学会の論文
2008-04-15