Combine Harvesting 85

Combine Harvesting-85
Project Leader and Principal UC Investigators G.E. Miller, Cooperative Extension J. Knutson, Cooperative Extension B. M. Jenkins, Department of Agricultural Engineering, UC Davis S. Upadhyaya, Department of Agricultural Engineering, UC Davis	SPIKETOOTH AND RASP BAR CYLINDER PERFORMANCES Objectives Objectives were to determine differences in spiketooth and rasp bar cylinder performances at different cylinder speeds and clearances in harvesting four different rice varieties. Grain yields, head rice yields, and grain moisture percentages were measured ac harvest time. Field trials were completed in the fall of 1984, and a preliminary report was made last year. Cylinder Types Compared Two John Deere 8820 combines were equipped, one with a spiketooth cylinder and the other with a rasp bar cylinder. A total of 156 harvester tests were made on four rice varieties. The rasp bar cylinder had a more gentle action, resulting in a higher head rice yield but also higher grain losses. However, the differences between cylinder types were relatively small and, for some varieties, no differences were found. The differences were insufficient to recommend one cylinder type over the other. Cylinder speed comparisons showed that as cylinder speeds increased, head rice and grain losses decreased. An increase in cylinder clearance increased head rice and grain losses. From the point of view of returns to the grower, these cylinder adjustments tended to be somewhat compensating within the ranges used in these trials. However, M-9 showed greater returns at the higher cylinder speeds, M-201 showed greater returns at the lower cylinder speeds. California Belle and M-401 returns were highest ac intermediate speeds. Grain Moisture and Varietal Differences Grain moisture during the harvesting trials ranged from 15 to 23 percent. The three medium grain varieties (M-9, M-201 and M-401) all showed improved head rice with increased grain moisture, but they also showed greater grain losses with increased moisture content. The long grain variety, California Belle, had the opposite response. Head rice increased at the lower moisture contents down to 16 percent. California Belle head rice increased 4.5 percent for each percent decrease in grain moisture at milling. The tests were at relatively low moisture percentages (9 to 12.7 percent). Since all samples graded No. 1, is does not appear chat the increase in head rice was the result of under milling at these lower moisture levels. It is not known whether this is a characteristic of all long grain varieties or is specific to California Belle. Further studies should be conducted on all varieties to determine optimum milling moistures.

Combine Harvesting-85

Project Leader and Principal UC Investigators

G.E. Miller, Cooperative Extension

J. Knutson, Cooperative Extension

B. M. Jenkins, Department of Agricultural Engineering, UC Davis

S. Upadhyaya, Department of Agricultural Engineering, UC Davis

SPIKETOOTH AND RASP BAR CYLINDER PERFORMANCES

Objectives

Objectives were to determine differences in spiketooth and rasp bar cylinder performances at different cylinder speeds and clearances in harvesting four different rice varieties. Grain yields, head rice yields, and grain moisture percentages were measured ac harvest time. Field trials were completed in the fall of 1984, and a preliminary report was made last year.

Cylinder Types Compared

Two John Deere 8820 combines were equipped, one with a spiketooth cylinder and the other with a rasp bar cylinder. A total of 156 harvester tests were made on four rice varieties.

The rasp bar cylinder had a more gentle action, resulting in a higher head rice yield but also higher grain losses. However, the differences between cylinder types were relatively small and, for some varieties, no differences were found. The differences were insufficient to recommend one cylinder type over the other.

Cylinder speed comparisons showed that as cylinder speeds increased, head rice and grain losses decreased. An increase in cylinder clearance increased head rice and grain losses. From the point of view of returns to the grower, these cylinder adjustments tended to be somewhat compensating within the ranges used in these trials. However, M-9 showed greater returns at the higher cylinder speeds, M-201 showed greater returns at the lower cylinder speeds. California Belle and M-401 returns were highest ac intermediate speeds.

Grain Moisture and Varietal Differences

Grain moisture during the harvesting trials ranged from 15 to 23 percent. The three medium grain varieties (M-9, M-201 and M-401) all showed improved head rice with increased grain moisture, but they also showed greater grain losses with increased moisture content.

The long grain variety, California Belle, had the opposite response. Head rice increased at the lower moisture contents down to 16 percent. California Belle head rice increased 4.5 percent for each percent decrease in grain moisture at milling.

The tests were at relatively low moisture percentages (9 to 12.7 percent). Since all samples graded No. 1, is does not appear chat the increase in head rice was the result of under milling at these lower moisture levels. It is not known whether this is a characteristic of all long grain varieties or is specific to California Belle. Further studies should be conducted on all varieties to determine optimum milling moistures.