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ARS Home » Research » Publications at this Location » Publication #87633
Title: SOYBEAN MOISTURE CONTENT MEASUREMENT BASED ON IMPACT FORCE PARAMETERS

Author
item STEWARD, BRIAN - UNIV OF ILLINOIS
item HUMMEL, JOHN

Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/13/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Previous work has shown that the force-time curves of impacting soybeans vary as functions of the moisture content of the soybean. This paper documents the effort to characterize the nature of the relationship between a parameter developed from the force-time curve and the soybean moisture content to see if impact force sensing would be a feasible way to measure real-time moisture content for yield monitoring applications. Soybeans from two cultivars (Jack and Conrad) were selected and treated to create an ensemble of samples at different moisture content levels. Individual beans from these samples were impacted against a force impact sensor, and the force-time curve was captured and stored. The mass of each bean was measured. A parameter, C, based on the peak force of the force-time curve and the duration of the peak was calculated from the curves. C was regressed onto moisture content using a quadratic model. The model fit the data with R2=0.84 and 0.76 for the Conrad and Jack cultivars, respectively. The variability in C increased as moisture content decreased, and the strength of the relationship between C and moisture content decreased with increasing moisture content. The introduction of mass into the model resulted in only a small increase in R2. Samples of the same two cultivars were collected during the 1997 harvest and used as a validation data set. The moisture contents of these samples were determined gravimetrically. Individual beans from each sample were impacted, and the force-time curves were recorded. The mean C for each sample was used to predict moisture content. The impact measurement technique predicted moisture content within 4% and 13% of the gravimetric measurements for the Conrad and Jack cultivars, respectively.