营养液深度对砂培漂浮育苗的影响

Effects of Liquid Nutrient Depth on Float Seedlings Cultured in Sand

为找到砂培烟苗生长最适宜的营养液深度,减少加液的用工成本,进行了不同加液深度试验。结果表明:①从播种到大十字期(转漂前)适宜的加液深度为1.5～2.5cm,加液太浅(1～1.5cm)则加水次数过多,用工成本增加,加水太深(3cm)则砂体泄漏,出苗率与烟苗存活率低(10.3%);②从出苗率90%到转漂前必须采取"干湿交替"的水分管理,"干"的砂体含水率为4%,"湿"的砂体含水率为20%,4～8d为一个周期;③砂体含氧量保持在5mg/L左右,有利于烟苗根系的有氧呼吸,成苗时存苗率、壮苗率高,根体积大,否则蓝绿藻、病害发生严重,存苗率降低。

In order to find the best fit liquid nutrient depth for float seedling cultured in sand and reduce labor ,st, different depth trials were conducted. The results showed that ： 1 ） the appropriate liquid depth was 1.5 - 2.5 cm from seeding to 4 true leaves stage, shallower liquid needed more frequent refilling, hence more labor cost, while deeper liquid caused sand leak and lower germination rate and seedling livability resulted; 2） sand body moisture should be alternated between dry and wet states every 4 -8 days from the time when seedling germination rate reached 90% to 4 true leaves stage, the moisture content in dry sand body was 4% and in wet sand body was 20% ; 3） maintaining oxygen content in sand body at about 5 mg/L would benefit to the aerobic respiration of root system and raised the rates of existence and vigorous seedling, and root volume. Otherwise, blue-green algae and diseases would outbreak seriously and deteriorated the existence rate of seedling.