Engineering - 69



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Combine performance tests were conducted with a special rice harvester on September 9, 1969, in a field of standing Calrose rice. Another set of tests was conducted on September 26, 1969, in a field of completely lodged rice.

Harvesting losses of 10% of field yield in standing rice can be expected at harvesting rates slightly greater than 160 sacks per hour. In down rice this loss level can be about 150 sacks per hour, and at times about double that amount. Separation loss was generally much greater than cylinder loss over a wide range of harvesting conditions.

Field tests are planned for the 1970 harvesting seasons to establish typical performance curves in standing and lodged rice for the walker and shoe of the combine. Some modification of either or both of these components of the combine may be attempted to improve the performance at and above the harvesting rate of 160 sacks per hour. A better balance between cylinder and separation capacity at the higher harvesting rates should increase the net return per acre almost in proportion to the decrease in harvesting loss.


A brief introductory study was conducted in the 1969 harvest season. Samples of rice were secured from the combine, shelled (hulled) on a McGill laboratory huller, dried, and stored in shallow pans under office conditions, and fatty acid indices were determined three months later. The results do not allow final conclusions but the following observations may be considered:

1) Hulling is best at low moisture content.

2) Rancidity is associated with high moisture content, but may also be accelerated in hulled rice.

3) The required hulling rate under normal combining conditions is much higher than that of commercial mills (about 110 lb. per min., max.).

If satisfactory field hulling and storage can be developed, the problem of hull disposal at the mill will be solved.

Tentative plans for 1970-71 are some carefully planned and executed pilot studies to secure more accurate data on hulling and free fattv acid development.


A research effort for the development of a stripper harvester for rice was initiated on March 1, 1970, utilizing A Grant-In-Aid contributed by Deere & Company.

In the 1970 harvest season small rice strippers will be used on campus rice plots. The mechanism which appears most promising will be developed into a full-scale rice harvester for field trials in 1971. Tests will be carried out in 1970 to determine parameters (plant anchorage, straw strength, etc.) which would be useful for the design and construction of a rice stripper prototype.


In a cooperative project with Chevron Research Company of Richmond, California, spray-applied coatings were used in 1969 to stabilize a rice levee at the University rice project test site. Also, a portion of a canal supplying water to the project was coated. The coatings were water-based emulsions containing modified asphalts and polymers. All showed weathering properties superior to those of ordinary asphalt coatings. Additional evaluation will be required to determine stabilization benefits for machine-formed levees. The most promising of the materials are being tested with a commercial applicator in 1970.


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