Abstract
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 fer 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 increased 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 from 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 one 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.
본 시험은 제주지역에서 양마의 적정질소시비 횟수를 구명하기 위하여 2001년 4월 13일부터 10월 8일까지 질소시비량을 240kg/ha 고정하고 30일 간격으로 1~5회 분시하여 양마의 생육특성, 사료수량성 및 조성분 함량 등을 조사하였다. 초장은 분시 횟수가 많을수록 증가하여 4회 분시구에서 최고인 201cm를 보이다가 5회에서 줄어들었다. 분지수, 엽수, 경직경 및 개체당 무게도 초장과 같은 경향으로 4회 분시에서 가장 우세하였다. 생초, 건물, 조단백질 및 TDN 수량은 전량기비에서 4회 분시까지는 각각 91.8MT/ha에서 114.2MT/ha, 12.70MT/ha에서 16.6MT/ha, 1.75MT/ha에서 2.48MT//ha, 5.39MT/ha에서 7.63MT/ha로 증수되었다가 그 이상인 5회 분시에서 각각 106.6MT/ha, 15MT/ha, 2.32 MT/ha, 7.22MT/ha로 감소되었다. 조단백질, 조지방, 가용무질소물 및 TDN 함량은 13.8%에서 15.4%, 4.1%에서 5.9%, 18.7% 에서 19.1%, 42.4%에서 48.1%로 증가된 반면 조섬유와 조회분은 각각 38.2%에서 37.1%, 11.5%에서 8.6%로 감소되는 경향이었다.