Page:The New International Encyclopædia 1st ed. v. 05.djvu/74

* CLOVER. 56 CLOVER-INSECTS. Clovers are of great value to agriculture, on account of the many ilitVerent ways in which they may be utilized. Clover is fed as hay, as green fodder, and as silage, and it is used for pasturage, for green-manuring, and as a cover- crop. It is chieflj' valuable as a means of en- riching the soil, being capable of appropriat- ing free nitrogen from the air by means of its roots. It has long been recognized that clover- growing has a beneficial eflect on the soil ; but this phenomenon was not understood until about 18S8, when scientists discovered that leguminous plants, through the agency of bacteria living in the characteristic tubercles or nodules on the roots, take Tip free atmospheric nitrogen. In the soil this nitrogen is oxidized to nitric acid, which fcrms nitrates, and in this form the nitrogen is assimilated by growing plants. In addition to their power of taking up free nitrogen, clovers are very valuable because of the large and deep development of their root systems, which effects a marked improvement in the physical condition of the soil, and thus indirectly increases its fer- tility. Plowing clover luider for green manure is a most effective method of adding humus to the soil. During recent years crimson clover is rec- ommended in the United States as a cover-crop for orchards, to be sown late in suinmer when the soil is no longer cultivated, and to be plowed under the following spring. In this way the soil is kept moist, its surface is kept from harden- ing, and much available plant-food is afforded the trees for the following season's growth. In general, the common red clover is the most im- portant in the United States. Feeding Value. — On an average red clover (green crop) has tlie following percentage com- position: Water, 70.8; protein, 4.4; fat, 1.1; nitrogen-free extract. 13. .t; crude fibre, 8.1; min- eral matter 2.1. Red-clover silage contains — - water, 72.0; protein. 4.2; fat. 1.2: nitrogen-free extract, 11.6; crude fibre, 8.4; ash, 2.6 per cent. Red-clover hay contains — water, 1.5. .3: protein, 12.3; fat, 3.3; nitrogen-free extract. 38.1; crude fibre, 24.8 ; and ash, 6.2 per cent. Other clovers and their cured products resemble the above quite closely. Clover forage is relatively highly nitrogenous, is relished by all farm animals, and is capable of replacing in part more expensive concentrated feeding-stuffs — such as bran, lin- seed meal, etc. Clover is very important for soiling, as it is available early in the season, and is relished. Pigs do well on clover pasture, building good bone and framework, and fatten rajiidly later on when given concentrated feed. Clover is very succulent in the green, nncired state, and there- fore, like all such feeds, liable to cause bloat, if too much is eaten. Animals should not be turned on clover pasture when very hungry, or while the dew is on the clover. Some dry fodder should be placed in racks in the pasture, as this is said to relieve bloat. Clover hay is not usually considered a satis- factory coarse fodder for horses, as the dust it carries proves detrimental. A limited amount may. however, be fed to all kinds of horses, with favorable results. It is a very satisfactory coarse fodder for milch cows. It furnishes the protein essential for milk, and is relished by the animals. By feeding clover hay as one-half to two-thirds of the coarse fodder of a ration, the amount of concentrated feed required may be diminished, and thus the cost of the ration low- ered. For calves and young stock, clover hay is very im])urtaut. No other coarse fodder is supe- rior for sheep. As shown by experiments with ruminants, the following ])ercentages of the nutrients in red- clover forage are digestible: Dry matter, 66.1; protein. 67.0: fat, ti4.5 ; nitrogen-free extract, 77.6; crude fibre, 52.6; and ash. 55.0 per cent. Red-clover hay has the following digestibil- ity: Dry matter, 57.4; protein, 58.0; fat, 55.2; nitrogen-free extract, 64.4 ; crude fibre, 54.2 ; and ash, 2!).l per cent. In this respect it compares favorably with other coarse-fodder crops, both green and dry. Clorcr Diseases. — There are two important fungus diseases of clover — a 'rust,' and what has been designated as the 'clover-rot.' The rust iVromi/ces trifolii) is said to have first been noticed in South America, and to have come to the United .States by way of Europe, where it is quite destructive. It infests the leaves, leaf- stalks, and stems, producing definite brown spots. The fungus passes through three phases — the first on the white clover, upon which mi- nute cups are formed, filled with orange-colored spores; the other two phases, red and black (so called from the color of the spores occurring on red clover), are quite destructive. When a por- tion of a field is found affected, it is best to cover the clover with straw and buin it to prevent further spread. The 'clover- rot' (Sclerotinia tri- foliorum) occurs on crimson clover in the Unit- ed States, although common on red and other clovers in Europe. It also occurs on alfalfa, sainfoin, fenugreek, Bokhara clover, etc. Its presence may usually be noted by all plants being killed in patches a foot or more in diame- ter. Small black bodies will be seen at the base of the wilted stems in the autunm, followed by the appearance of small mushroom-like bodies in the spring. Burning, as mentioned above, and rotation of crops, are recommended for its sup- pression. A leaf-spot disease {Pseudopeziza tri- folii) is sometimes quite destructive to clover and alfalfa. The disea.sed leaves show on their upper surfaces small black specks, which enlarge and extend through the leaf, destroying it. When present, this disease is liable to become epidemic, causing considerable loss. Burning over fields in autumn and frequent cutting pre- vent serious loss to the crop. Another destruc- tive parasite of clovers, although not a fungus, is the dodder (q.v.). CLOVER - insects! Various insects in- juriously affect cultivated clover, of which the following are prominent: The roots are attacked by borers, and the stems by a gall-making bee- tle t LfiDfniria ^[oz<lrdi) : also by a cutworm, the larva of the zebra-moth (q.v.). Weevils do great injury to clover in various parts of the plant; the worst .species {Hi/lcsiniis trifolii) is an im- portation from Europe. These minute beetles pair in early spring, and then the female gnaws a cavity in a root of two year-old clover and places it in four to six eggs. The larvic, as soon as hatched, bore along the .axes of the roots of the clover, causing the plants to weaken and often to die. Another beetle (Pliytonoinus punctatus), called the clover leaf-beetle, sometimes appears in swarms, coiling about the tips of the leaves. The leaves are also attacked by a midge or gall- gnat, and the seeds by another (C'evidoiinjiu Icgti-