Comparative study on different simulation models of flue-cured tobacco LAI variation under salinity condition

Abstract

In order to simulate the dynamic changes of flue-cured tobacco leaf area index (LAI) and predict the tobacco yield under different salinity and fertilizer levels, a field experiment with six treatments for flue-cured tobaccos was carried out at a plastic sheet covered greenhouse in south China, and three models including the linear model, exponential model and crop growth model were used to simulate the tobacco LAI dynamic changes varying with days after transplanted. Results showed that the dynamic change of LAI presented a single-peak curve, and the changes of LAI could be divided into three stages, including the slower growth period, the acceleration period and the recession period. The linear simulation model, exponential simulation model and the crop growth model could well simulate the dynamic changes of flue-cured tobacco LAI, with the correlation coefficient of 0.8738∼0.9027, 0.9964∼0.9985 and 0.9924∼0.9972, respectively; the linear model had the same parameter number as the exponential simulation model, but the simulation accuracy of which was poorer than that of exponential simulation model. Although the crop growth model had more parameters to fit, most of the parameters had practical significance and were conducive to provide useful information for the LAI simulations and predictions. In general, the exponential model and the crop growth model were more satisfactory in simulating the dynamic changes of LAI since they possessed the better simulation precision, and the deciders could consider using the crop growth model or the exponential model according to the actual requirement: if the more comprehensive information of tobacco LAI was needed, the crop growth model should be the first choice; and if the simpler calculation process and shorter calculation time were required, then the exponential simulation model could be firstly taken into consideration.