| In order to realize the dynamics irrigation prediction for the soybean in northeast of Inner Mongolia, the polynomial fitting method was applied to interpolate the suitable soil moisture lower limit value for each day in whole soybean growth period, to form the dynamic index curve for the suitable soil moisture index lower limit. Started from the point of view of soil-plant-atmosphere continuum, based on the theory of soil water balance, using the soil moisture data and meteorological information from 2001 to 2007 of agricultural meteorological station in Tuquan County of Inner Mongolia, was set up the dynamic irrigation forecasting model for soybean that was suitable to the dry farming area in northeast of Inner Mongolia, to realize the time domain rolling forecast for the irrigation date and irrigating. The model simulated results were verified by the observed data from 2008 to 2011. The root mean square error(RMSE) and the mean absolute percentage error(MAPE) between the predictive and measured values of relative soil moisture were 2.44% and 3.42%, respectively. The error between the forecasting and actual irrigation date was within ±3 days. It indicated that accuracy and practicability of the model were rather strong. The research results can be provided certain scientific basis for developing water saving irrigation in soybean producing area of Northeast China. |