Effects of the level of fertilizer input on tiller and leaf development in relation with dry matter accumulation of napiergreass and kinggrass

Synopsis WADI, A., Y. ISHI and S. IDOTA (2003) : Effects of the level of fertilizer input on tiller and leaf development in relation with dry matter accumulation of napiergrass and kinggrass. Grassland Science 49, 311-323. Tiller and leaf development of napiergrass (Pennisetum purpureum) and kinggrass, the hybrid between napiergrass and pearl millet (Pennisetum typhoides), was measured under three levels of chemical fertilizer supply during the growing season. Plants were grown in 1/2000 a wagner pot by transplanting single tillers under natural conditions in 1999 and 2000. Emerged tiller number (ETN) and regrown tiller number (RTN) increased with the increase in the level of fertilization. Rate of tiller emergence (RTE), rate of leaf expansion (RLE) and individual leaf area (LA) were generally larger in 1999 than in 2000 for both grasses by the doubled level of fertilization and tended to increase at the higher nodal positions with the increase in the level of fertilization. Sum of individual leaf area (SILA) on the main shoot was positively linearly related with mean leaf area per tiller (LA/T) and LA/T was with leaf area index (LAI) at all levels of fertilization. Crude protein concentration in stem with leaf sheath was linearly related with ETN in August 1999, and individual LA was almost positively related with daily effective mean temperature. The increases in RTE, RLE and SILA were concurrent with the increase in LA/T, which was directly related with that in LAI, leading to the increase in dry matter accumulation in both grasses, under the higher input of fertilization. Within the levels of fertilization examined, higher input cost of fertilization obtained higher return of dry matter at the competitive price with the commercial roughage.