Abstract: Simulation model system was a key part of precision agriculture, which provided the precision decision. The most important factors in tobacco precision farming were nitrogen, phosphorus, potassium and water. So it was necessary to study how much fertilizer and water was absorbed by tobacco in its growing time, what was importance to keep the tobacco production continual development. A pot experiment and a field experiment were done in this paper to reveal the relationship between output value and the four factors. Used traditional statistics and geo-statistics, two mathematic models were established by the design of quadric circum-regression basis on the spatial variability analysis of soil available nutrient. One-factor analysis showed that the output value went up first and then went down with the fertilization of nitrogen and the soil water content went up, but it always kept going up with the fertilization of phosphorus and potassium went up. Base on the consequence one-factor models were individually established. Two-factors analysis indicated that there was a range value to show the interaction of two-factors between nitrogen and water, phosphorus and water, potassium and water, nitrogen and phosphorus, nitrogen and potassium. The interaction of two-factors was cooperation when the quantity of fertilization and the soil water content was small than the range value, but when it was large than the range value the interaction of two-factors was noncooperation. The interaction of two-factors between phosphorus and potassium was always cooperation in experiment. After that, the amount of fertilization was optimized base on established mathematics models, and as a result indicated that the optimum fertilization of pure nitrogen, P2O5, K2O was individually range from 4.852g to 5.445g, 7.677g to 8.637g, 16.168g to 17.948g in pot experiment, and from 2.45kg/667m2 to 3.04kg/667m2, 3.77kg/667m2 to 4.77kg/667m2, 16.05kg/667m2 to 16.73kg/667m2 in field experiment, the soil water content ranged from 75.8% to 80.5% in pot experiment, and from 75.2% to 80.8% in field experiment.

Key words: Tobacco, Precision agriculture, Model, Fertilizer, Water