The annual lespedezas serve to control erosion in the summer. The soil loss from a field in lespedeza has been recorded as 148 tons of soil per acre during the months of June to September in clusive, as compared to 17.87 tons from an adjacent field of cot ton. Even the debris from a lespedeza field has materially aided in checking erosion during winter. Lespedeza sericea makes so dense a canopy during the growing season that the heaviest rains cannot beat upon the bare ground. During winter the great root system and the living crowns hold the soil. The ability of this species to grow on soils already badly eroded places it in the first rank of plants useful to the soil conservationist. It is used in buffer strips on sloping cultivated fields as a permanent cover on land too badly eroded to be worth cultivating, for the control and healing of gullies, and for the control of critical slopes.
Lespedeza is not so dependent on lime as red clover, but on soils that are decidedly acid, it will respond to applications of lime. Most Southern soils are also deficient in phosphates and lespedezas respond markedly to an application of superphos phate. Indeed on the poor soils of the coastal plains, the common lespedeza does not make a profitable crop without the application of phosphate.
While economic conditions made it necessary for farmers in the lespedeza territories to turn to this crop in order to save their lands, it should not be forgotten that a continuance of careless farming with lespedeza will lower the fertility level still more. Every crop takes something from the soil in which it is grown and lespedeza, when removed as hay or pasturage also removes from the land some lime, phosphorus, and potash.
If these are not replaced, the time will come when even lespe deza will not thrive. Lespedeza has revolutionized the agriculture of a great region and saved thousands of farmers from economic ruin. It can continue this service only if proper attention is paid to the need of the crops and soils for plant food.
over the entire United States is about one ton per acre, although two or even three tons per acre have been cut under favourable conditions. While the lespedezas are quite drought resistant, good hay production is possible only under conditions of abundant rainfall or on low moist ground. The amount of growth made is directly proportional to the moisture available. On high dry ground, the lespedezas make growth enough for grazing, but not for hay. Hay is cut when the plants are in full bloom. For Korean this will be from the first to the middle of August or a little later in the northern part of its range. Earlier cutting in July will favour a second growth which may be taken for hay or seed. The earlier cut hay is also of superior quality. L. striata, being later, is cut somewhat later in the season.
A first volunteer stand usually makes the most and best hay. In older fields, the weeds tend to invade and the hay becomes of lower grade. Good hay can be made from L. sericea, but the plants should be cut when the spring growth is about one foot high. Cut at this stage, the hay is palatable, tender, and of high quality. Later the stems tend to become woody, the leaves shatter more readily and the hay is of inferior quality. L. seri cea contains tannin, which, in the mature plant, may be as much as I o% of the total weight. In the early stages of growth the tannin content is low and the protein content is high. With advancing age these positions are reversed, as the protein con tent falls the tannin content rises. For the best hay, therefore, the plants should be cut when young. The lespedezas contain less water than alfalfa and must not be left long in the swath. On good drying days, lespedeza can be cut in the morning and housed before night.
More important is the use of pure lespedeza for summer pastur age. Used in this way, cattle are grazed on grass early in the season and in July when the grass becomes semi-dormant, they are moved to a field of lespedeza. There they remain until fall when the grass renews growth.