STUDIES ON THE DRY-MATTER PRODUCTION OF NAPIERGRASS .5. THE REGIONAL DIFFERENCES IN THE DRY-MATTER YIELDS OF LEAF BLADE, STEM AND DEAD PARTS

Dry matter yields of the leaf blade, the stem with leaf sheath and the dead parts of napiergrass, Pennisetum purpureum Schumach, cv. Merkeron in the first year of growth were compared among Tokyo, Nagoya, Fukuoka, Miyazaki, Naha and Iriomote Island. Yield of the leaf blade at the final harvest in the plants grown without cutting was lower at the southern sites. However, the regional differences in the yields of the stem and the dead parts of the above plants and yield of each part of the plants harvested at early- or middle-August, were not related with the regional differences in the length of productive period and the climatic conditions. In the aftermath by the cutting mentioned above, yields of the leaf blade and the stem were higher at the southern sites. The productive structure and the feeding value to ruminants of the uncut plants and the aftermath, in terms of dry matter yield of leaf blade and yield ratio of stem to leaf blade, were significantly correlated with cumulative temperature and were inferior at the southern sites. © 1990, CROP SCIENCE SOCIETY OF JAPAN. All rights reserved.