Dear Dr. Richard Ogoshi and modellers: Thanks a lot for your help trying to solve MPLAG in CERES-rice. I have been trying to solve this equation but couldīt get satisfactory results. I began with the first leaf so CUMPH=1, and followed CUMPH BF CUMPH-BF XTN DTT PHINT PC TI MPLAG 1 0.12 0.88 -23.33 19.2 83 0.728 0.3177 2.49E-7 1.3177 0.12 1.1977 -32.06 19.1 83 0.7496 0.3070 4.06E-11 1.6247 0.12 1.5047 -43.58 19.05 83 0.7705 0.2979 4.32E-16 XTN= -9.678*EXP(-BF+CUMPH) PC = 0.66 + 0.068 * CUMPH TI = DTT / (PHINT * PC) MPLAG = A / CUMPH * (-BF) * XTN * EXP(XTN) * TI without stress A= 3800 MPLAG: daily growth of leaf area per plant (cm2/plant) is decreasing when the number of leaves is growing up, I think that there must be something wrong here, but I canīt detect it. I have a plant population of 337,9 emerged plants per m2. When calculating how simple leaf area varies with leaf number, I got this: CUMPH A/CUMPH*(-BF)*XTN*EXP(XTN) 1 7,85E-7 1.3177 1.323215E-10 1.6247 1.448522E-13 I found the when the number of leaves is going up, the leaf area descends. What is your opinion?. I will be appreciated. Is BF the previous day leaf area or previous day leaf number? Sincerely yours: Luis E. Alvarez L. Universidad Ezequiel Zamora. UNELLEZ. Guanare. Estado Portuguesa. Venezuela.