Assessment Method for Soil Environmental Quality Based on BP Neural Network

The calculating method of neural networks is a new way to discuss problems by simulating the mechanism of activities of human body network systems. Soil environment quality assessment was a difficult problem in environment research. In the paper BP neural network based on MATLAB 6.x and its application in soil environment quality assessment were introduced and the assessment program was built in this paper. The influencing factors of BP neural network on soil environmental quality assessment were discussed, which were the input vector, the numbers of neurons in the hidden layers and the training process. Using the interpolation function rand or linspace in building the input vector is feasible. The transfer function of hidden layer is tansig and the numbers of neurons ale five or eight when the interpolation function is rand or linspace, while, the transfer function of output layer is purelin and the number of neuron is one, The addition of noise in the input vectors is important to improve the correction of the network. Based on the research results, the constructed network was applied to a case of soil environmental quality assessment and the assessment results were compared with other assessment methods, which suggested that the method of BP network in soil environmental quality assessment was feasible and reasonable.