Sweet Clover: Harvesting and Thrashing the Seed Crop

Part 1

Transcriber Note

Text emphasis is denoted as Italics. Whole and fractional parts of numbers as 123-4/5.

SWEET CLOVER

HARVESTING AND THRASHING THE SEED CROP

H. S. COE

Assistant Agrononmist, Office of Forage-Crop Investigations

FARMERS' BULLETIN 836 UNITED STATES DEPARTMENT OF AGRICULTURE

Contribution from the Bureau of Plant Industry

WM. A. TAYLOR, Chief

Washington, D. C. July, 1917

Show this bulletin to a neighbor. Additional copies may be obtained free from the Division of Publications, United States Department of Agriculture

WASHINGTON : GOVERNMENT PRINTING OFFICE : 1917

SWEET CLOVER should be cut for seed when three-fourths of the seed pods have turned dark brown to black. At this time some flowers and many immature pods will be found on the plants, but the field will have a brownish cast.

Sweet-clover seed pods shatter badly when mature. For this reason every precaution should be taken to cut the plants at the proper stage and to save as much of the shattered seed as possible.

Shattering may be reduced to a minimum by cutting the plants when they are damp from rain or dew.

No machine thus far placed on the market has given entire satisfaction in cutting sweet clover for seed.

The ordinary mower should not be used for harvesting the seed crop. The seed crop is usually cut with a self-rake reaper, grain binder, grain header, or corn harvester. The self-rake reaper and the grain binder have been most satisfactory.

The seed crop should be stacked unless it can be thrashed within two weeks after cutting.

Much shattered seed will be saved if a wagon with a tight floor is used for hauling the plants. If the wagon bed is not tight it should be covered with a tarpaulin or canvas.

The seed may be flailed from the plants, as is customary in the South, or it may be thrashed with a grain separator or clover huller, as is the practice in the North.

The ordinary grain separator may be adjusted so that it will hull 90 per cent of the seed.

Sweet-clover straw has considerable feeding value.

SWEET CLOVER: HARVESTING AND THRASHING THE SEED CROP.

This bulletin discusses only the harvesting and thrashing of the sweet-clover seed crop. The growing of sweet clover and its utilization are discussed in Farmers' Bulletin 797, entitled "Sweet Clover; Growing the Crop," and Farmer's Bulletin 820, entitled "Sweet Clover: Utilization," respectively.

CONTENTS.

Page.

The crop to harvest for seed 3

Time to cut the seed crop 4

Part 2

Loss of seed from shattering 4

Machinery used for harvesting the seed crop 5

Stacking the sweet-clover seed crop 17

Thrashing the sweet-clover seed crop 18

Yields of sweet-clover seed 21

Sweet-clover straw 23

THE CROP TO HARVEST FOR SEED.

White sweet clover and biennial yellow sweet clover are harvested for seed the year following seeding. In localities where those species will produce two cuttings the second year, either the first or the second crop may be harvested for seed. As the plants die when mature, only one cutting will be obtained if the first crop is permitted to ripen. It is becoming a general practice in many sections of the country to utilize the first crop of the second season for pasture, ensilage, or hay, and the second crop for seed. As a rule, this is the most profitable and economical way to handle sweet clover, as the first crop will produce an abundance of nutritious pasturage or from 6 to 10 tons of ensilage or 1 to 3 tons of hay to the acre. The second crop seldom grows more than 4 feet high when the first crop is pastured or cut. The shorter growth of the second crop is a very desirable feature, as it may be cut with a grain binder without difficulty. When the first crop of white sweet clover is permitted to mature, the plants often make so large a growth that it is very difficult to handle them with ordinary farm machinery. This trouble is experienced more often in humid regions than in semiarid sections.

As biennial yellow sweet clover seldom grows as tall as the white species, little difficulty is experienced in cutting the first crop of the second year for seed with a grain binder. Annual yellow sweet clover, or sour clover, is seldom grown for seed, as a sufficient quantity to supply the market is obtained from the screenings of wheat grown in the Southwest.

Sweet-clover seed ripens irregularly and shatters badly when mature. On this account much seed is lost before and during harvest, and ordinary harvesting machinery has not been entirely satisfactory for handling the crop.

TIME TO CUT THE SEED CROP.

Opinions of extensive growers of sweet clover differ as to the proper stage at which to cut the seed crop. Some believe that it should be cut when the pods on the lower branches have turned dark brown to black, while others maintain that it is best to wait until the seed on the upper portions of the plants is mature. The time of cutting the seed crop should be governed largely by the machinery which is to be used. If the plants are to be harvested with a self-rake reaper or a grain binder, they should be cut when approximately three-fourths of the seed pods have turned dark brown to black. At this time some flowers and many immature pods will be found on the plants, but the field will have a brownish cast. If the crop is not cut until the seed pods on the uppermost branches have matured, most of the pods on the lower branches will have shattered.

It is the practice in regions where a grain header is employed to permit the plants to become somewhat more mature before cutting the seed crop than in sections where other machines are used. More seed is shattered when the plants are cut at the latter stage, but this is not necessarily a loss, as the grain header is employed for the most part in semiarid regions, where the shattered seed is depended upon to reseed the land.

LOSS OF SEED FROM SHATTERING.

From one-fifth to three-fourths of the total seed yield of sweet clover is lost from shattering. The percentage of the loss which occurs before harvesting will depend largely on the time the crop is cut. Much seed may be lost if harvesting is delayed for only a few days, and many fields have been observed in which at least 90 per cent of the seed had shattered in less then two weeks after the time the plants should have been cut.

The percentage of seed which is lost in harvesting will depend largely upon the manner of handling the crop. The binder or header may be equipped at a small cost, so that much of the seed which ordinarily is lost while cutting may be saved. Much shattered seed will be saved by using wagons with tight platforms or platforms covered with canvas. All unnecessary handling should be avoided.

Shattering may be reduced to a minimum by cutting the plants when they are damp from rain or dew. It is the practice in some regions to cut in the early morning or late evening, but this procedure will apply only to small acreages, since it is necessary to cut the crop as soon as possible when it reaches the proper stage for harvesting. It is a good practice to cut sweet clover at night, as the plants usually are damp at that time.

MACHINERY USED FOR HARVESTING THE SEED CROP.

No machine thus far manufactured has given entire satisfaction for cutting the sweet-clover seed crop. On account of the ease with which the pods shatter, it is a question whether any machine can be devised which will handle this crop without the loss of some seed. It is possible and practicable, however, for farmers at a small cost to equip their binders with pans and guards, so as to save most of the seed which otherwise would be lost.

THE ORDINARY MOWER.

The ordinary mowing machine is one of the most unsatisfactory devices used for harvesting this crop, as the subsequent handling necessary to place the plants in windrows or cocks causes much of the seed to shatter. The use of this machine for this purpose should be avoided whenever possible.

THE SELF-RAKE REAPER.

The self-rake reaper is one of the most efficient machines employed to cut sweet clover for seed. (Fig. 1.) This machine deposits the newly cut plants with the tops all turned one way in gavels or bunches at the side, so that the horses do not trample them on the next round. A high stubble also may be left, thereby reducing the weight and bulk of the plants which must be hauled to the thrashing machine.

It is the custom in some localities to leave the gavels to cure as dropped by the reaper on the ground, while in other sections they are placed in cocks that weigh about 300 pounds each when cured. If the gavels are to be placed in cocks, this should be done immediately after cutting, as the plants will be somewhat green and tough at this time and fewer pods will shatter than when the plants are permitted to dry before handling. When the crop is to be hauled to the thrashing machine on wagons it is best to permit the gavels to cure as dropped by the reaper, as it will then be possible to pitch them on the wagon with a large 4-tined fork. If the crop is to be hauled to the thrashing machine on large sleds, which is the practice in western Kansas, less seed will be lost from shattering if the gavels at the time of cutting are placed in cocks of such a size that they may be put on the sleds entire by two men lifting from opposite sides of the cock with 4-tined forks. The sleds used for this purpose usually are 12 by 20 foot in size, made of matched flooring and with 6 to 12 inch sides. (Fig. 2.) Matched or tight floors are necessary, so that all seed which shatters may be saved. These would not be so essential, however, if the sleds were covered with a tarpaulin or canvas. From the standpoint of saving shattered seed, this method of hauling the crop from the field to the thrashing machine is possibly the most economical thus far used. It is estimated that at times as much as one-third of the seed yield is collected from the floors of the sleds. It would be a good plan to replace the runners of the sleds with very low trucks, as this would lighten the draft considerably.

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