Dear colleagues



I used the DSSAT4 to simulate the rice in Northeast China at four site using the same cultivar coefficient.

site 1 (N46.44, E129.53), site 2 (44.20, 129.28), site 3 (45.50, 128.48),and site 4 (44.54, 127.09). the model gave good results for site 1 (maturity period 157, and grain yield 8644, which agree with the observed data), but simulated very long maturity period, 485 days for site 2, 784 days for site 3 and 808 days for site 4,and very low grain yield, less than 300kg/hm2, which very differ to the observed data. I could not get the satisfied simulation result whatever adjusting the cultivar coefficient or changing the inputs (sowing date, planting density, etc.). After comparing the weather data of there four sites, I found it's not the temperature problem because the four sites has same temperature analogue, sites 1 is the coldest and wettest site . 



I held that the rice model has some problem when it was be used in a cold environment for it was based on the warm environment. Do anyone has faced there problem before? and can provide me some solution to use the DSSAT RICE in cold environment. 



Many thanks in advance



Xiong wei