Research On Nondestructive Testing Technology For Rice Water Shortage Information

Water is one of the important factors that need to be maintained in the continuous growth and physiological processes of rice.The water condition of the leaves can directly reflect the water deficit of the plants.However,how to predict the moisture content of rice leaves quickly and without damage,there is still no complete system detection method.In this paper,rice leaves under drought stress were used as research objects.Five kinds of electrical parameters such as impedance Z,impedance phase angle?,effective resistance Rp,effective capacitance Cs and loss coefficient D were measured by LCR impedance analyzer and other equipment.These parameters were used to detect the moisture content of rice leaves.The mathematical model of the relationship between electrical characteristics and rice moisture content was established.The reliability of the model was compared and analyzed.The main research contents and conclusions of this paper are as follows:1.A parallel clamping clamp capable of non-destructive measurement of the electrical characteristics of rice leaves was designed.The LCR impedance analyzer and self-made fixture can be used to accurately measure the electrical parameters of rice leaves.2.Five electrical parameters and water content data of 87 rice samples with different water content at 25 different frequency points were collected.Five electrical parameters of rice leaves with different water content after drought stress treatment at 25 frequency points were measured by LCR impedance analyzer.The moisture content of rice leaves was detected by dry weight loss method.3.Through experimental data analysis and modeling research,it is found that the nonlinear moisture content prediction model established by the combination of principal component analysis(PCA)and multilayer perceptron neural network(MLC)modeling method is the best.4.There is a strong correlation between the water content of rice leaves and its corresponding five electrical parameters,and the correlation coefficient R~2reaches 0.778.It is feasible to predict the water content of rice leaves by using electrical characteristic parameters.The study provides a rapid non-destructive testing method for rice drought prediction.