본 시험은 옥수수 재식밀도 low(67,000 plants/ha), control(89,000 plants/ha) 및 high(95,000 plants/ha)를 주구로, 질소 시비량 150, 200 및 250kg/ha을 세구로 하여 분할구 배치법 3반복으로 2001년부터 2002년까지 2년간 축산연구소 한우시험장에서 수행하였다. 옥수수의 간장은 재식밀도가 낮을 수록 길었고, 모든 주처리구에서 ha당 200kg의 질소 시용구에서 길었으나 처리구간에 유의성은 인정되지 않았다. 또한 옥수수의 착수고는 재식밀도가 높아질수록 낮았으며, ha당 150 kg 시용구에서 가장 낮았으나 유의적인 차이는 나타나지 않았다. 옥수수의 암이삭 비율은 재식밀도가 낮을 수록 높아지는 경향이고 질소시비 수준은 ha당 200kg이 높았다(P<0.05). 옥수수의 건물수량은 재식밀도가 높아짐에 따라 증가를 하는 경향이었으나 유의적인 차이는 보이지 않았고 재식밀도에 따라 질소시비 수준은 차이를 보였다(P<0.05). 옥수수의 조단백질 함량은 큰 차이는 없었으나 높은 재식밀도와 낮은 질소시비 수준으로 가장 높은 경향이었다. NDF와 ADF 함량은 낮은 재식밀도와 200kg/ha이 가장 높았다. 이상의 결과를 종합하여 건물수량과 사료가치를 고려하여 보면 고랭지에서 낮은 재식밀도(67,000 plants/ha)와 ha당 150-200kg의 질소시비 수준이 적당할 것으로 생각된다.
This study was conducted to investigate the effect of the planting densities and nitrogen levels on the growth characteristics, dry matter yield and nutritive value of corn for silage in alpine area(altitude 800m a.s.1.) of National Livestock Research Institute from 2001 to 2002. The experiment was arranged in a split plot design with three replications. Main plots consisted of three planting densities, low(67,000 plants/ha), medium(89,000 plants/ha) and high(95,000 plants/ha). Sub plots consisted of three nitrogen levels, 150 kg/ha, 200 kg/ha, and 250 kg/ha. Tassel height of corn was increased with decreasing planting density, and nitrogen level of 200 kg/ha in all main plots. Ear height of corn was decreased with increasing planting density, and 150 kg/ha of three nitrogen levels. But there were no significant differences among treatment in tassel and ear height. Although dry matter ear ratio of whole com was increased with decreasing planting density, there were no significant differences among treatments. But there were significant differences among nitrogen levels(P<0.05). Dry matter yield of com was high with increasing planting density, but there were no significant differences among treatments. And DM yield of corn was significant difference among nitrogen levels(P<0.05). Crude protein content of corn was the highest with high planting density and low nitrogen level. NDF and ADF content of com was the highest with low planting density and nitrogen levels of 200 kg/ha in all main treatments. These results indicate that low planting density(67.000 plants/ha) and nitrogen of 150-200 kg/ha would be the optimum level fur dry matter yield and nutritive value of silage com in alpine area.
