Effects of Cutting Height and Trampling over Stubbles of the First Crop on Dry Matter Yield in Twice Harvesting of Forage Rice

摘要

We examined the effects of cutting height and trampling over stubbles of the first crop on dry matter yield in twice harvesting of forage rice Oryza sativa L., Tachiaoba and Taporuri. Dry matter yield of the second crop, after the first harvest at the full-heading stage, increased with increasing cutting height. However, the dry matter yield of the first crop decreased with increasing cutting height. Overall, total dry matter yield did not vary with the cutting height. Dry matter yield and its components of the second crop were not greatly affected by the trampling treatment. At cutting heights of 15 and 5 cm from the base, the number of tillers developed from unelongated nodes was increased by the trampling treatment. Thus, although the number of tillers developed from the elongated nodes was decreased after the trampling treatment, the decrease is compensated for by the increased number of tillers from unelongated nodes.