Plant communities of grazed pastures converted from paddy fields, 1: Vegetation on pastures with variable grazing years
2007
Tsutsumi, M.(National Inst. of Livestock and Grassland Science, Nasushiobara, Tochigi (Japan). Nasu Research Station) | Itano, S.
Conversion of paddy fields into pastures for use by grazing cattle is an important option for animal production and conservation of agricultural land in Japan. However, trampling by animals on the high-moisture soil in the converted pastures may lead to degradation of sown forage species and generation of weeds. This study investigated vegetation characteristics and soil moisture content in three paddy-field pastures varying in grazing history. Pastures T (first to second years of grazing), N3 (third year) and N8 (eighth year), and also in a pasture in an upland field as a control (Pasture C, second year). Botanical composition was determined using the dry-weight-rank method. The soil moisture content was highest in Pasture N3, followed by Pastures T, N8 and C. The number of paddy-field weed species occurring in Pastures T, N3, N8 and C was 10, 16, 8 and 1, respectively. The dominance by paddy-field weeds was higher in Pasture N3 than in Pastures T and N8. The proportion of total weeds (paddy-field+non-paddyfield type) in plant biomass was lower in Pasture T than in Pastures N3 and N8. The proportion of paddy-field weeds in the total weeds decreased as the grazing year increased.
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