New Sugar-Beet Machinery

by S. W. McBIRNEY THE SUGAR-BEET crop is one of our last field crops to be mechanized. Sugar beets have been grown commercially sixty-odd years in the United States and the acreage had increased to nearly a million at the beginning of the war. Yet at that time blocking and thinning the crop in the spring, and the harvest operations of topping and loading in the fall were still largely done by hand.

Thinning, topping, and loading are the three jobs in which mechanization can save the most, because when they are done by hand they make up 60 to 75 percent of the total manual labor, which amounts to 75 to 120 man-hours an acre.

Engineers got encouraging results from their early investigations of equipment and methods for mechanical blocking and thinning in the 1930's, but the early trials showed that the then common practice of planting about 20 pounds of seed an acre in 20-inch rows, largely with fluted feed drills, produced thick and irregular stands of seedlings that were not well suited to mechanized thinning.

The first major step leading to mechanization of the spring hand work was the development of single-seed planting, by agricultural engineers in the California and Colorado agricultural experiment stations and the Department. The new way to plant produced much more uniform seed distribution, so that the rates of seeding could be decreased and the seedling stands could be thinned more rapidly.

Single-seed planting of smaller sized screened seed, furthermore, produced stands that were even better because they contained more single plants. The reason is that sugar-beet seed actually are seed balls that vary from about one-eighth to one-quarter inch in diameter and contain from one to five or even more true seeds or germs per ball; the smaller balls contain fewer germs.

Single-seed planting proved so promising that one manufacturer of beet planters began building special equipment in 1939 to adapt his plate-type planters for the new method of planting. Commercial adoption of the planting began, and others began to build suitable equipment.

The second major step in improved planting was the development of segmented or sheared seed-that is, seed with fewer germs per segment. That work began in 1941 at the California Agricultural Experiment Station at Davis. The machine developed at Davis has an enclosed, coarse-grit grinding wheel and a stationary hardened steel shear bar set to give a desired clearance between it and the wheel. Beet seed is fed down onto the grinding wheel from a hopper. The revolving wheel carries the seed by the shear bar and, because of the restricted clearance, part of the seed ball is broken away and the size of the seed unit is reduced. The seed is then cleaned and graded to a suitable size and quality.

Usually the recovery of segmented seed is from 40 to 50 percent of the original weight, but the number of seed units recovered is usually not much less than that of the original seed. The degree of singleness obtained by the segmenting process varies with adjustments. Whole seed averaging two sprouts per viable ball is commonly reduced to seed averaging 50 to 60 percent of viable segments as singles; some average 70 to 80 percent.

The development of segmented seed fitted in ideally with single-seed planting, as seed segments have to be planted singly to get the maximum benefit from the segmenting. Old-style planting does not benefit from segmented seed. Furthermore, the benefits of single-seed planting increase as the percentage of singleness of the seed unit increases. The development of both the seed processing and the planting equipment has been continued throughout the war years and commercial acceptance has been rapid. In 1941 segmented seed planted with a suitable planter was used on only an acre or so. The large savings possible in thinning labor were so apparent and the need for labor saving was so great that several thousand acres were planted in 1942. By 1945 more than 80 percent of our commercial sugar-beet acreage in the United States was planted with segmented seed.

The best present practice is to use single-seed planting of good segmented seed in well prepared seed beds at seeding rates of around 4 to 5 pounds an acre, often even less. Such planting is now saving beet growers thousands of man-hours of tedious hand work. Even where the beets are thinned by hand, as in the past, the thinning labor can be reduced about a fourth. Thinners prefer this planting and will often pass up old-style plantings with whole seed for the newer type. Furthermore, this planting is much better suited to mechanized thinning and where long handled hoe or machine thinning is used, the manual labor can be reduced to a fourth or less.

A great deal of investigation has been done on mechanical harvesting. Many experimental machines have been devised and much work has been done on them. For many years the problems seemed insurmountable. One by one, the difficulties are being overcome. Four different types of harvesters were made in 1946, and several others were being developed.

The first harvester to be manufactured on a rather large scale is a single row, two-unit machine adapted, at first, only to more friable soils. It tops the beets in the ground, windrows the tops, digs the beets, and kicks them back onto a conveyor, which windrows them. The windrowed beets are later loaded into beet trucks with a separate loader. The topping is done well and the tops are left in excellent condition, either for immediate loading and ensiling or for field curing for stock feed. The harvester was originally built by a Colorado beet grower in much its present form in 1940 and 1941. It looked so promising that it was taken over by a manufacturer who continued developing it. Since 1943, 200 or 300 machines have been built each year; with them, nearly all of the machine harvesting of beets outside of California was done up to 1946 and many thousand tons have been harvested. Further work is being done on it with the aim of adapting it to a wider range of conditions.

A second, completely different type of harvester has been developed in California primarily to meet conditions there. It is a large, spiked-wheel machine built in one-row and two-row models; a large tractor is needed to pull it. A lighter draft, single-row model has been designed that may be suited to other areas. With this harvester, untopped beets are loosened in the row and then picked up by the spikes on the 6-foot wheel. Topping chisels remove the beets from the spiked wheel at the top and a sickle cuts off any leaf streamers on the beets. Beets are cleaned from dirt on a roll-type screen and are elevated directly to a truck. Beet tops and adhering soil are scraped from the wheel and onto the ground.

Topping done by the machine is slightly poorer than ordinary hand topping, but sugar factories have found it acceptable. It does not leave beet tops in particularly good shape, but a better method of top handling is under development. The machines, particularly the two-row models, have large capacity, and seem to be a reasonably satisfactory answer to California's harvest problem. More than 30 percent of California's 1945 beet crop and nearly 60 percent of its 1946 crop were harvested by these machines, some two-row machines harvesting more than 500 acres each Season. The grower's cost per ton harvested for one company in 1945 on 10,000 acres was $1.28, compared to $2.13 a ton for hand harvest.

A third harvester, in commercial production for the first time in 1946, is of still another type. It utilizes hand sorting of topped beets from clods where necessary on heavier soils and has shown this method to be practical and economical. Operations in 1945 by farmers using these machines where hand sorting was necessary showed that the hand labor required for harvest could be cut to a third of that normally required. The cost of harvest could be reduced one-third to one-half by use of the harvester. Where hand sorting was not needed on friable soils, the labor and cost of harvest could be still further reduced. This machine tops beets in the ground, then digs, cleans, and elevates them to the sorting table, if needed, or drops them directly into a trailer-hopper if no clods are present. The beets are transferred from the trailer by a built-in elevator to beet trucks. The topping is done well, but the tops are dropped back directly onto the ground in only fair shape. A suitable method of top handling is being developed, however. The beets are clean and the machine can be used on dry, cloddy soil where other machines have failed. It is a single-row harvester having a capacity of about 2 1/2 acres a day.

The fourth harvester, in commercial production for the first time in 1946, is a single-row machine that plows the untopped beets loose and lifts them by the tops. They are elevated into the machine where they are topped and then delivered directly into a truck driven alongside. The tops are dropped back onto the ground one row at a time. A top wind-rower is under development. The machine eliminates the problem of clods by lifting the beets by the leaves, but it is necessary to have good leaf growth on the beets. So far these harvesters have gone into the Michigan-Ohio territory where, in 1946, they took out about 7 percent of the crop.

Thus, mechanical harvesting is coming into its own. Before 1943 the commercial acreage harvested by machine was negligible; in 1944 it was 7 percent. Approximately 12 percent of our beet acreage in 1945 was machine harvested. In 1945, about 400 harvesters were manufactured; in 1946, the estimated number was 1,200.

THE AUTHOR S. W. McBirney is an agricultural engineer in the Bureau of Plant Industry Soils, and Agricultural Engineering. He is in charge of the sugar-beet machinery research project of the Bureau and has been working on the mechanization of the labor peaks of the sugar-beet crop for several years. His outstanding work has been on the mechanization of the spring work, particularly on the development of single-seed planting and low seeding rates. He is a graduate of Iowa State College and began his work with the Department in 1927.