在甘薯育苗中,烂床的主要原因,一是病烂:种薯带有黑斑病、软腐病、茎线虫或肥料床土带菌。另外,冷、涝、伤口也会引起烂床;二是熟伤:床温长期在40℃以上,易发生热伤,使种薯发软,挤压时流出清水,肉色发暗;三是水烂或闷气缺气:床土紧实不透气或浇水过多,或封膜后长期不通气引起缺氧烂床。其防治方法如下: 1.防治病害侵染。苗床要用无病菌的净土、净圈粪;严格精选无病,不受冷害、涝害和破伤的种薯。在甘薯、上床前用50％多菌灵粉剂800—1000倍液,对防治黑斑病有较好的效果;用51—54℃的温水浸种10分钟,不仅对黑斑病有明显防效,还能兼治薯皮内0.5厘米深处的茎线虫。 2.严格控制床温。从排种到出苗阶段,床温应控制在31—35℃为宜,最高不得高于38℃。排种后1天使床温上升到31℃左右,以后渐增,第5天要把床温升到35℃左右,高温催芽后,将床温降到31℃左右。出苗后到 In sweet potato seedling, the main reason for rotten bed, one is sick rot: seedpot with black spot disease, soft rot, stem nematode or fertilizer bed soil bacteria. In addition, cold, waterlogging, wounds can also cause rotten bed; Second, cooked injury: bed temperature over 40 ℃ for a long time, prone to thermal injury, so soft seed, squeezed out of water, fleshy hair dark; Third, water Rotten or sulky gas lack of gas: tight soil tight airtight or watering too much, or long-term non-ventilated after the film caused by anoxic rotten bed. The prevention and treatment methods are as follows: 1. Prevention and control of disease infection. Seedbed to use pure soil without disease, the net ring feces; strict selection of disease-free, not cold damage, waterlogging and broken seed. In sweet potato, before going to bed with 50% carbendazim 800-1000 times, the prevention and treatment of black spot disease has a good effect; with warm soaking 51-54 ℃ for 10 minutes, not only has significant control of black spot disease, Also cure both within 0.5 cm deep tuber nematode. 2. Strict control of bed temperature. From seed to seedling stage, bed temperature should be controlled at 31-35 ℃ is appropriate, the maximum shall not be higher than 38 ℃. Bed temperature after 1 day to raise the bed temperature to about 31 ℃, after the gradual increase in the fifth day to bed temperature rose to about 35 ℃, high temperature germination, the bed temperature dropped to 31 ℃ or so. After emergence