Effects of soil temperature,water stress and sowing depth on germination and emergence of maize

The germination experiments were carried out both in laboratory and in fields.Results showed that when soil water content was lower than 10%,maize germination would be constrained.Large temperature difference will accelerate germination rate by comparision of the thermal time for Gt50 between laboratory and field results,and among field results of different sowing date.Thermal time reqired for 50% seed germination was at 18.6 to 23.8 ℃ ds depending on the difference in temperature.Sowing depth affected the rate of emergence. When sowing depth was increased from 5cm to 8cm,time repuired for 50% emergence was increased by half a day,and for 80% emergence by one day.