Sweet Clover: Harvesting and Thrashing the Seed Crop

by H. S. Coe

Much of the sweet-clover seed harvested in the South is flailed from the plants. This method is necessarily slow and does not hull the seed. It is practicable, therefore, only in regions where the necessary machinery for hulling the seed crop is not available or where the acreage to be thrashed is very limited. One advantage of thrashing the seed in this manner is that the straw is left in the field, where it will add much organic matter to the soil.

When the seed is to be flailed, the crop ordinarily is cut with a scythe or mowing machine and the plants raked into piles or windrows. If only small areas are to be harvested in this manner, a canvas or tarpaulin may be spread on the ground beside a windrow or pile and several forkfuls of sweet clover pitched on the canvas, where the seed may be removed from the plants by striking them a few times with flails, sticks, or forks. After the plants have been struck a few times they should be turned over and struck again. When the seed is removed front the plants, the straw may be pitched to one side, the canvas placed beside another portion of the windrow or by another pile, and the operation repeated. It is not necessary to remove the seed from the canvas until its weight or bulk interferes with moving the canvas.

It is the practice in some sections of the country to place a well-braced frame, covered with wire netting, on a sled and to flail the seed on this frame. The netting used for covering the frame should have meshes 1 inch or loss in diameter. The sled should be at least 7 feet wide and 10 feet long and should have sides and ends approximately 12 inches high. Smaller sleds sometimes are used, but a larger one is to be preferred if two or more persons are to flail on it at one time. If the floor of the sled is not perfectly tight, it should be covered with canvas and the edges of the canvas thrown over the sides and ends of the sled, so as to avoid losing any of the seed and to facilitate its removal. A sled so equipped may be drawn from pile to pile, the plants pitched on it, the seed flailed from them, and the straw returned to the land for soil improvement.

Another method, very similar to that just described, is to place a frame on a hayrack. The frame should be built sufficiently strong and in such a manner that the person who is to do the flailing may stand on it. It should be covered preferably with galvanized-wire netting having half-inch meshes, and if this is stretched tightly it will serve to strengthen the frame. If it is not practicable to make the hayrack perfectly tight, it should be covered with a tarpaulin or canvas. A wagon so equipped may be pulled from pile to pile or along the windrows, where one person may pitch the plants upon the frame, to be flailed by one or more persons standing on it. After the seed is removed from the plants, the straw may be scattered easily and quickly over the ground for soil improvement.

Flailed seed should be cleaned thoroughly with sieves and fanning mills to remove the inert matter and immature pods before it is sown or offered for sale on the market. It is recommended that whenever possible unhulled seed be run through a clover huller to hull the seed or through an Ames hulling and scarifying machine to remove the hulls and to scarify the seed. By this process the outer coat of the seed is scratched or broken. The scarifying increases the percentage of germination by facilitating the entrance of moisture.

Fig. 13.—Thrashing sweet clover with a grain separator. Note the large sleds used for handling the plants from the field to the thrashing machine.

THE GRAIN SEPARATOR.

A grain separator ([fig. 13]) is used more than any other machine for thrashing sweet clover. This is because more grain separators than clover hullers are found in localities where sweet clover is grown and because the ordinary clover huller will not handle a large growth of sweet clover satisfactorily. When the grain separator is operated carefully no trouble should be experienced in removing the seed from the plants, but it is necessary to make certain adjustments if the seed is to be hulled. The adjustments required will vary somewhat with the make of machine and the dryness of the crop. The riddles should be adjusted or changed so they will handle sweet-clover seed properly. Alfalfa or red-clover riddles will answer this purpose. The speed of the fan should be decreased, so the seed will not be blown over, and this usually will be accomplished when the speed is reduced to about one-half that used in thrashing grain. The number of rows of concave teeth which should be used will vary with the dryness of the plants and somewhat with their size. When it is not desired to hull the seed, one or two rows of concave teeth will be sufficient. Some operators believe that one or two rows are sufficient to hull 40 to 50 per cent of the seed when the plants are very dry. Those are exceptional cases, and hulled seed should not be expected unless more rows of concave teeth are used. If hulled seed is desired it is recommended that a full set be used and that these be set to run closer to the cylinder teeth than is customary when thrashing grain. Some operators replace two rows of the smooth, concave teeth with corrugated teeth. This practice is recommended wherever possible, as the corrugated teeth will facilitate greatly the hulling of the seed. Even where these changes are made, only a small percentage of the seed will be hulled if the pods are damp. If the plants have been permitted to make a very large growth the machine may clog unless the number of rows of concave teeth is reduced. Clogging may be overcome for the most part by feeding the bundles to the machine slowly. This precaution is necessary regardless of the size of the plants if the seed is to be removed properly and hulled. It is possible to hull from 90 to 95 per cent of the seed when the proper adjustments are made and the plants are dry.