Abstract
A field experiment was carried out to compare the nitrate nitrogen concentration, sugar content and animal intake of low $sorghum{\times}sudangrass$ hybrids (Sorghum bicolor (L.) Moench) grown under application of animal manure in 1995. The application amount of animal manure were 40MT in cattle manure, and 30MT/ha in swine and poultry manure. The four NLCF's recommended hybrids used in this study were Pioneer 988, TE-Haygrazer and NC+ 855 (heading type), and Jumbo(headless type). The nitrate nitrogen concentration of forage was 365mg/kg at 50~60cm of plant height, 501mg at 100~120cm, and 502mg at 200~220cm, regardless of animal manure type and cultivar. The nitrate nitrogen concentration of NC+ 855 and P 988 was 519 and 526mg, respectively, and were higher than that(317mg) of Jumbo(P<0.05). The nitrate nioogen concentration of stems was 376mg, and significantly higher than that(135mg) of leaves(P<0.05) regardless of cultivar, and lower parts of stems and leaves were higher than those of upper parts of plants. The sugar contents of four $sorghum{\times}sudangrass$ hybrids were ranged between 3.1 and $3.7^{\circ}$ in cattle manure, 2.9 and $3.3^{\circ}$ in swine manure, and 2.8 and $4.9^{\circ}$ in poultry manure. The sugar content of NC+ 855 was the highest as $3.9^{\circ}$, p 988 was second as $3.4^{\circ}$, and then TE-Haygrazer and Jumbo were lower as $3.2^{\circ}$ and $2.9^{\circ}$, respectively. Animal intake of sorghum ${\times}$ sudangrass hybrids P 988 and NC+ 855 were slightly higher than those of Jumbo and TE-Haygrazer grown under application of cattle manure. Also the average intake of P 988 was a little higher than that of Jumbo. However, there were no significant differences of forage intake among few recommended $sorghum{\times}sudangrass$ hybrids.
본 시험은 가축분 시용 조건에서 $수수{\times}수단그라스$ 교잡종중 우리나라에서 많이 재배하고 있는 장려품종 4종(P 988, Jumbo, TE-Hay-grazer, NC+ 855)을 공시하여 생육시기별, 잎과 줄기의 부위별 질산태 질소 함량과 당도 및 가축 기호도 등을 구명하였다. 가축분은 톱밥과 50:50으로 섞은 발효분으로 ha당 우분 40톤, 돈분 및 계분은 30톤을 파종 보름전 시용하였으며, 파종은 ha당 30kg의 종자를 휴폭 50cm로 1995년 4월 21일에 실시하였다. 수수${\times}$수단그라스 교잡종의 질산태 질소 함량은 초장 50~50cm일 때 365mg/kg, 초장 100~120cm일 때 501mg, 초장 200~220cm일 때 502mg이었으며, 품종별로는 Jumbo에서 평균 317mg으로 낮았고 P 988(526mg)과 NC+ 855 (519mg)에서 높았다(P<0.05). 또 품종에 관계없이 줄기(376mg)가 잎(135mg)에 비해 질산태 질소함량이 크게 높았으며(P<0.05), 같은 잎과 줄기에서는 아래부위로 갈수록 질산태 질소 함량은 유의적으로 증가하였다(P<0.05). 품종별 당도는 NC+ 855가 평균 $3.9^{\circ}$ 로 가장 높았으며, 다음이 P 988($3.4^{\circ}$), TE-Hay grazer ($3.2^{\circ}$), Jumbo($2.9^{\circ}$) 순이었다. 채식률은 P 988과 NC+ 855에서 Jumbo와 TE-Haygrazer에 비해 다소 높은 경향이었으나 장려품종 4종간 유의적인 채식률 차이는 없었다.
