穴盘水稻秧苗拔秧力试验研究

从育秧穴盘中拔秧时，秧苗状况和营养土含水率是影响秧苗脱离穴盘的重要因素。在适宜的营养土钵含水率范围内的机械手拔起穴盘水稻秧苗所需的拔秧力试验表明，1穴秧苗所需的拔秧力为0．4～0．8N，小于1穴1株秧苗茎部所能承受的拔断力（平均为3．732N）；同一穴中秧苗株数对拔秧力基本无影响；多穴秧苗的拔秧力随穴数的增加而增大。营养土含水率越低，拔秧力越大，拔秧效果越差，达到过饱和时，拔秧力也会增加。拔秧时，适宜的营养土含水率为27％～29％（湿基）。

Experimental Study on the Force of Pulling up the Rice Seedlings Sprouted in the Plastic Cell-tray

The experiments on the force of pulling up the rice seedlings from plastic cell-tray are done under appropriate range of nutritious soil-ball water contents firstly. The results show that the average force of pulling up single-cell rice seedlings from plastic cell-tray one time is about 0.4~0.8 N, smaller than the fracture force of one single rice seedling at stem (average 3.732 N). The number of rice seedlings in one soil-cell and white roots growing out bottom small hole of the tray hardly have any effects on the force of pulling up the cell. The force of pulling up different cells of rice seedlings one time increases as increasing of the number of cells. The experiments are done that the nutritious soil-ball water content affects the force and quality of pulling up rice seedlings from the plastic cell-tray secondly. The results show that nutritious soil-ball water content is lower, the pulling force is larger and the quality of pulling up rice seedlings is worse. On the other hand, the pulling force also can increase small when the nutritious soil-ball water content is in saturation condition. The appropriate range of nutritious soil-ball water content is about 27%~ 29% (w.b.) for pulling up rice seedlings form plastic cell-tray.