Effects of Ridge-up Bed Cultivation on the Fruit Quality of Satsuma Mandarin ('Miyagawa Wase') in a Plastic Film House

높은이랑재배에 의한 하우스 밀감의 품질향상

This experimemt was conducted to determine the effect of ridge-up bed with different height (0, 20, 40, 60 cm) on the fruit quality of 'Miyagawa Wase' satsuma mandarin cultivated in a plastic film house. Soil moisture was measured at the soil depths of 10, 30, and 60 cm for each height of ridge-up bed. The time required to reach the condition, -1.4 Mpa at 30 cm deep in soils, which are supposed to be the ideal soil moisture potential and soil depth for high quality satsuma mandarin production, was 100, 60, and 30 days for 20, 40, and 60 cm ridge-up bed, respectively, and more than 100 days for 0 cm. Peel chromaticity by 'a' value was increased as the ridge-up height went up, so that plants grown at the bed with 60 cm height had 11 degree higher value than those of plants grown at the bed with 0 cm height. The 'a/b' values also had a similiar trend as value 'a'. The reducing sugar level of the fruit juice, which was composed of glucose and fructose, was increased as the height of ridge went up, showing significant difference between the ridge heights. The sucrose level had the same trend as the reducing sugar level although the difference between the ridge heights were not significant. Generally, the soluble solid level is considered to be representing the fruit quality. It had 11.4, 12.1, 12.5, $12.8^{\circ}Brix$ for 0, 20, 40, and 60 cm ridge-ups, respectively, showing $1.4^{\circ}Brix$ difference between 0 and 60 cm ridges. Acidity basically showed the same result as that of the soluble solid level depending on the height of the ridges.

이랑높이가 하우스밀감의 품질에 미치는 영향을 구명하고자 이랑높이를 0, 20cm, 40cm, 60cm로 하여 궁천조생과 흥진조생을 공시하고, 토양수분 및 품질의 변화를 조사하였다. 하우스밀감의 고품질 생산에 필요한 토심 30cm에서의 토양수분포테셜이 -1.4Mpa이 되기까지는 평휴에서 100일 이상, 20cm에서 100일, 40cm에서 60일, 60cm에서 30일이 소요되었다. 착색도 a는 이랑높이가 높아질수록 증가되어 평휴에 비해 60cm 이랑에서 11이나 증가되어 이랑높이에 따른 착색 촉진효과가 현저하였으며, a/b도 이와 유사한 경향을 나타내었으나, 품종간에는 차이를 인정할 수 없었다. 포도당과 과당으로 조성된 환원당은 이랑이 높아질수록 증가되는 경향이 뚜렷하였고 포도당에 비해 과당 함량이 많은 편이었다. 자당은 환원당과 유사한 경향을 나타내었으나 환원당에 비해서는 낮은 편이었으며, 품종간에는 이랑높이에 따른 차이가 없었다. 실제적으로 하우스밀감의 품질을 대표하는 당도는 평휴, 20, 40, 60cm 이랑에서 각각 11.4, 12.1, 12.5, $12.8^{\circ}Brix$로 평휴에 비해 60cm 이랑에서 $1.4^{\circ}Brix$나 증가되는 효과를 가져왔으며, 산도도 이와 유사한 경향을 보였다.