蔬菜無土栽培之研究（一）砂與（石至）石對縐葉萵苣、莧菜生長之影響

Studies on Vegetables in Soilless Culture (1) The Effect of Sand and Vermiculite on Growth of Curled Lettuce and Edible Amaranth

以10公分高之淺塑膠密籃為容器，栽培縐葉萵苣，在砂逕0.5-5mm範圍內，以0.5-1mm砂生長最好；籃底親以約2cm高真逕5-10mm石礫生長更佳，三者產量均高於肥土栽培者，（石至）石適於高溫，溫度低，蒸發力強之夏季栽培，因此夏天莧菜在（石至）石中生長最好。非洲（石至）石較日本（石至）石更適地高苣生長。砂與（石至）石混合可兼二者之長。冬播萵苣在83天生育期中地上部63%鮮重及64%灰分係在採收前13天中生長吸收的。無土栽培之萵苣品質好營養豐富，灰分含量高於用土壤栽培，水分亦高於一般栽培者。

A particle size of sand between 1 and 0.5 mm is suitable Lot intermmitent application when 10 cm depth shallow plastic basket is used as container. A double layer consisting of an upper one SCM deep with a particle size of 0.5 to 1 mm and a lower one 2 cm deep with a particle size of 5-10 mm is best tot curled lettuce (Lactuca saliva L. var. crispa, L) growth better than fertile scil. In summer season N. G vermiculte is very suitable for edible amaranth (Amaranlhus mangostanus, L.), but unsuitable in Taipei area where winter is cold heavy rainfall, cloudy and high humidity. The African vermiculite is better than N. G vermiculite on the growth of curled lettuce. Curled lettuce produced over 63% of their fresh weight in the 13 days immediately preceding harvest, and over 64% of ash uptake occured during this 18 day period. There is a tendency for plants grown hydroponically to be somewhat more succulent it than those grown in soil. The ash contents are higher than soil in curled lettuce.