Dear all:

I had been in touch with Dr. Richard Ogoshi since a long time. Now I have become the part of the DSSAT LIST Server. About my problem I want to contact to Dr. Ogoshi through this facility.
Dear Dr. Richard Ogoshi:

Thank you very much for the email. The problem I had about irrigation treatment came this way: 

1. I tried to callibrated three years rice experiments 1996, 1997 and 1999 with one expt file. I made one experimental file instead of three and put Year as variable (Field 1, 2, and 3). Irrigation treatment (IM) were also 1,2,3 and bund height under   IAMT was set to 100 and also IRVAL to 100. With this the irrigation output was reported only from the last year i.e. 1999. And earlier two years 1996 and 1997 did not express. I did this way because may be this is quicker and management and varieties are almost the same, except the soil condition may be a bit different. With this the genotopic coeficient came a bit different and higher that the limit such as G1. In fact according to manual, this value (G1) should remain around 55 although the range is from 10 to 500. To solve this I had to make some adjustment in the NH4-N and NO3-N inputs in the Initial Condition (IC). The 1997 NH4-N goes very high 24.0 ppm to get the same genotypic coefficent to be callibrated.

2.     Later I changed the file structure the other way. I made three separate file 1996, 1997 and 1999. I made the same input for irrigation. Now I can get the irrigation output getting expressed in each file output. Also the NH4-N in 1997 could be lowered to 11ppm to get the same genotypic coefficient callibrated.

1. My concern and query is why the outputs are different from the above two approaches ? Do you think that the first approach is wrong or I have to make additional adjustment in the file or in the simulation control? Please suggest.

2. My experience shows that NH4-N and NO3-N inputs in the IC are very sensitive. In our condition, usually we donot analyse these Ns. Our usual practice is to calculate the total N only. Can you suggest on this?

Thank you

Kishore Sherchand