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ARS Home » Pacific West Area » Pendleton, Oregon » Columbia Plateau Conservation Research Center » Research » Publications at this Location » Publication #166764
Title: ON-COMBINE SENSING OF GRAIN PROTEIN CONCENTRATION

Author
item Long, Daniel
item ENGEL, R - MONTANA STATE UNIVERSITY
item CARPENTER, F - INSTRUMENT DISTR INT'L IN

Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/2004
Publication Date: N/A
Citation: N/A

Interpretive Summary: Protein concentration is an important determinant of grain quality and ultimately the dollar value of cereal grains that qualify for price premiums. Spectroscopic analysis using either near infrared transmission (NIT) or near infrared reflectance (NIR) is often used to determine the protein concentration and moisture content of whole grain samples to <0.1%. Presently, utilization of this technology is largely limited to laboratory or indoor-type settings. With the advent of the Global Positioning System (GPS) and crop yield sensors, there is great interest in adapting NIT/NIR spectroscopy for use on combine harvesters. The ability to sense cereal grain protein as it is harvested could lead to changes in harvesting/grain handing procedures. This would result from being able to segregate the grain into fractions of low or high quality as needed to blend the grain in accordance with certain contract specifications of grain buyers. In addition, such a technology would allow protein mapping of cereal grain fields. Growers could then use grain protein maps to identify within-field spatial variability in soil N fertility levels otherwise difficult to resolve through soil sampling alone. This project evaluated an on-combine sensor for determining within-field variability in grain quality and mapping protein concentration for precision agriculture. Specific objectives were: 1) to assess the precision of the optical sensor during field operations with respect to NIT measurements obtained from a whole grain analyzer in the laboratory, and 2) generate protein yield maps from the optical sensor for selected farm fields. Practical uses of grain protein maps are described with application to modeling of crop N factors for precision N management, and modeling of straw yield for crop conservation planning.

Technical Abstract: Few producers use variable-rate technology to optimize wheat protein levels due to the lack of an accurate, cost-effective method to resolve spatial patterns of soil fertility in sufficient detail. The objective of the work in progress is to investigate the use of an on-combine spectroscopic sensor for identifying smaller areas within fields differing in grain protein concentration and soil N fertility, which is a determinant of grain quality. On-combine grain protein data for Hard Red Spring Wheat were acquired for farm fields in northern Montana. Preliminary results showed sensor-based measurements of grain protein to be correlated with test measurements of grain protein (R2=0.55, SEP <0.66%). The results are sufficiently promising to suggest that on-combine spectroscopic sensing is feasible. When combined with yield maps, maps of grain protein can be used to compute the spatial distributions of crop nitrogen (N) removal, N nutrition sufficiency, variable-rate N recommendations, and straw yield.