Fig. 5.—Stubble of sweet clover collected in fields where 90 per cent of the plants had been killed by cutting too closely to the ground. The heavy stands in these fields were not cut until the plants had made a growth of 36 to 40 inches. Note the scars on the stubble where young shoots started, but died from lack of light.
When fields of sweet clover contain only a medium-heavy stand and when the plants have made no more than a 30-inch growth, a 5 to 6 inch stubble usually will be sufficient to insure a second crop, but where fields contain heavy stands—15 to 25 plants to the square foot—it may be necessary to leave an 8-inch stubble. In many fields examined in northern Illinois in June, 1916, heavy stands had been permitted to make a growth of 36 to 40 inches before cutting. In a number of these fields a very large percentage of the plants were killed when an 8 to 12 inch stubble was left. (See [fig. 5].) A careful examination of such fields showed that the young branches had started on the lower portions of the stalks and had died from lack of light before cutting. In semiarid regions, where the plants do not make as rapid growth as in humid sections, they may, as a rule, be clipped somewhat closer to the ground without injury.
On account of the difference in the growth that sweet clover makes on different types of soil and on account of the difference in the thickness of the stand obtained in different fields, it is impossible to give any definite rule as to the proper height to cut the first crop.
Fig. 6.—Shoe sole to be placed on the inner shoe of the mower, so that a high stubble may be left when mowing sweet clover: A, End view of the back part of the sole; B, side view of the sole, showing general shape; C, shape of the front end of the pole when it is to be used on mowers having shoes of the type used on Deering machines; D, forward end of the sole represented in B. The toward end of the sole shown in B and D should be made for machines having shoes of the type used on McCormick mowers.
MOWER CHANGES FOR CUTTING SWEET CLOVER.
It is good practice to replace the shoe soles of the mower with higher adjustable soles, so that a stubble up to 12 inches in height may be left when cutting sweet clover, Shoe soles such as are shown in figures 6 and 7 may be made on any farm provided with a blacksmith's forge, or they can be made at any blacksmith shop at a cost which should not exceed $2.50. Preferably they should be of strap iron, about one-fourth of an inch thick and 2 inches wide; however, old pieces of iron or steel which may be found on the farm will serve the purpose.
