'Evegradies 71' kenaf (Hibiscus cannabinus L.) was grown at 160,000 plants per ha in a volcanic ash soil in Jeju island to determine the optimum frequency of split N application for forage production. Nitrogen fertilizer was applied with 240 kg/ha, a...
'Evegradies 71' kenaf (Hibiscus cannabinus L.) was grown at 160,000 plants per ha in a volcanic ash soil in Jeju island to determine the optimum frequency of split N application for forage production. Nitrogen fertilizer was applied with 240 kg/ha, and frequencies of the split N applications were 1, 2, 3, 4 and 5 times. Plant height averaged across two harvests increased from 187 to 201cm as N was split-applied from one to three applications and then decreased to 201cm in five applications. This pattern held for the number of branches and leaves per plant, stem diameter and weight of plant per plant. Fresh forage yield from 91.8 to 114.2 MT/ha, dry matter yield from 12.70 to 16.6 MT/ha, crude protein yield from 1.75 to 2.48MT/ha, and total digestible nutrients(TDN) yield form 5.39 to 7.63 MT/ha as N was split-applied from one to four applications, and then decreased to 106.6, 15.0, 2.32, and 7.22 MT/ha in five applications, respectively. As N was split-applied from on to five applications, crude protein content increased from 13.8 to 15.4%, ether extract content from 4.1 to 5.9%, and TDN content from 42.4 to 48.1%, but crude fiber decreased from 38.2 to 37.1% and crude ash content from 11.5 to 8.6%. Nitrogen free extract content was about 19.0% regardless of cutting height.