Research And Development Of The Detector For Determination Of Wheat Biomass Based On Mechanical Property

Crop biomass is an important indicator which can be used to reflect the status of crops. It has important significance for breeding wheat and production management to test wheat biomass of field by fast non-destructive measurements. Now, there has been no population-based study on crop biomass of non-destructive testing methods yet in China; the development of testing instruments in biomass is also blank.The article based on a pendulum-meter for determination of plant mass designed by Germany agricultural engineering institute. Firstly, when the force on the wheat stalks was analyzed deeply, the relation of the size, position, and direction of force and the deformation of wheat stalks were studied. And the same time, the data of the rebound forces from wheat stalks deformation was obtained by virtue of a pressure sensor in order to establish the functional relationship between the rebound force of wheat stalks and wheat biomass. Thus, it could be implemented to indirectly predict wheat biomass. Then, a new detector for determination of wheat biomass based on mechanical property was designed. The main research contents as follows:Firstly, the mechanical property of wheat stalks was studied, the optimum design schemes for the detector was determined, and the detector prototype was finished. The present study took the natural growth wheat as the analysis object to analyze the mechanical property of wheat stalks. The mechanical strength of wheat stalks could be analyzed based on the mechanics index of wheat bending performance such as elastic modulus, moment of inertia of cross-section, bending strength, flexural rigidity. Then, the measuring principle of wheat biomass was given. So the design work of the detector for determination of wheat biomass was done based on this measuring principle, and the key design parts of the detector mainly included sensor module, data acquisition module and some supporting platforms for each module. Some kinds of design schemes for the detector were designed by using3D entities modeling software UG NX. There were one guide tracked design schemes and a hand-held design schemes. Then, owing the detector measurement sensibility and rectilinear motion requirements, the optimum scheme was finally selected to finish the manufacture of the detector prototype for determination of wheat biomass.Secondly, the accuracy of measurement system of detector prototype for determination of wheat biomass was determined. By designing two experimental verification and multiple measurements, the discrepancy between YYD-1detector for measuring crop mechanical strength and measurement system of detector prototype was compared. It could be concluded that the measurement system of the detector prototype had good sensitivity and great accuracy, and could meet the wheat stalk in vivo measurement need.Finally, the detection experiments of wheat biomass in the field by vsing the detector prototype for determination of wheat biomass were made. In wheat maturity, the prototype measurement system was used for obtaining the data of the rebound forces of wheat stalks to compare discrepancy between measured values and theoretical values. The results showed that the measured curve of the reaction force basically tallied with its theoretically calculated result curve. Furthermore, through analyzing the discrepancy of the reaction force among the same wheat stalk but different action points, the stem mechanical strength in different stem nodes could be determined. And then the relationship between rebound forces of wheat stalks from the detector and wheat biomass aboveground was analyzed to obtain the correlation degree which was above0.86. Therefore, it could be concluded that the detector for determination of wheat biomass on predicting wheat biomass in field was feasible.This study can provide intelligent, portable and low-cost equipment for obtaining the biomass of field crops. The measurement data of biomass detector can also provide design reference for development of crop stalk detection instruments and harvesting machinery.