Rye as a Cover Crop.--As has been stated elsewhere, the plant that stores nitrogen in its organic matter is most desirable, but the greater part of the soil's stock of humus did not come through legumes. Among the good cover crops is rye, both on account of its ability to grow under adverse conditions and because it produces a large amount of material for the soil. When seeded in the early fall, its roots fill the soil the following spring, and the tops furnish all the material that can be plowed down with safety. In northern latitudes it is the most dependable of all winter cover crops, making some growth in poorly prepared seed-beds and on thin land. The most value is obtained from early seedings, thus securing a good fall growth. Two bushels of seed are sufficient in good ground seeded ten weeks before winter begins, but two or three pecks should be added to this amount if the rye can be given only a few weeks of growth before frost locks up the soil. Rye can grow in warm spells of winter, and starts early in the spring. It uses up some available fertility that might otherwise be lost, and releases it when it rots in the ground. When to plow Down.--If rye has made a good growth before spring, the roots run deeper than the plow goes, and holds the soil much like a grass sod. In such a case the plowing may be made early in the spring without regard to the rye, though organic matter increases rapidly day by day if the rye is permitted to grow. As a rule, it is safest to plow down before the plants are eighteen inches high. They dry land out rapidly, and any mass of matter in the bottom of the furrow interferes with the rise of water from the subsoil. When the land is wanted for oats or corn, a jointer should be used on the plow to insure burying all the crop. Buckwheat.--An excellent crop for green-manuring is buckwheat. It has such unusual ability to grow in a poor soil that the farmer who makes free use of it as a grain crop never boasts of acreage planted, assuming that his land will not be highly regarded if known to be devoted chiefly to buckwheat. It does not withstand heat well, especially from period of blossoming to maturity, and therefore is restricted to cool latitudes. When grown for grain, it usually is not planted until July, and matures a crop in a shorter period than any other grain. It is sensitive to frost, but may be planted as soon as the ground is warm, and will give a good body of matter for plowing down within eight weeks. The root growth is not extensive, but the crop leaves naturally heavy soils more mellow, and it is an excellent cleansing crop for weed-infested fields. It makes a less heavy growth than rye, but can be used at a time of the year that rye would fail. There is time in a single season to grow two crops of buckwheat for green-manuring, turning the first crop down when the blossoms appear.