The several figures and diagrams here shown illustrate what is meant by the map of the farm. It is simply an outline drawing showing the divi sion of the farm into fields, the location and plan of the building site, the location of lanes and roads, and the natural features which need notice, such as the groves, streams, draws, and the like. A careful survey of the farm will have to be made in order to locate properly the points and objects which need to be noted on the map. The map should be drawn accurately on a small scale, an inch to 50 or 100 feet. Almost any bright boy or girl, having exact measurements and distances and the area of the fields, with a little help can draw a map of this kind.
Soil management.
In the management of the farm, the handling of the soil is of the greatest importance. It is impossible to grow good crops on the same field year after year, except by thorough tillage and cultivation, the addition of fertilizers and the proper rotation of crops in order to maintain the fertility of the land. It has been truly said that "tillage is manure" to the crop. The plant-food of the soil is largely in an unavailable condition, and is made available for the use of plants only by the action of physical and chemical agencies. The presence of air and moisture is necessary that decomposition and chemical change may take place, by which the insoluble and unavailable plant-food elements are made soluble and available to the plants. Thus, tillage and cultivation, by aerating and pulverizing the soil, and by the conservation of soil moisture, make favorable conditions for the development of bacteria, hastening the processes of decomposition and chemical change which make the plant-food available.
Simple tillage, however, will not maintain the fertility of the soil. It becomes necessary finally to replace the plant-food, exhausted by the contin uous growing of crops, with the application of manure or chemical fertilizers or by the rotation of crops, in which the legume crops, such as alfalfa and clover, are introduced in order to restore again the humus and nitrogen. When land has been farmed a long time in wheat or corn, it finally ceases to produce profitable crops. The soil is not neces sarily exhausted in fertility, but by a long period of continuous cropping with one crop the diseases and insects which prey on the crop have accumu lated in the soil, and the organic matter and humus and nitrogen have become more or less exhausted. The land is really "wheat sick" or "corn sick," as the case may be ; what it needs more than any thing else is a rotation of crops, which shall include legumes and grasses, by which the organic matter, exhausted by continuous cultivation and cropping with one crop, may be restored.
Grass is a soil-protector, a soil-renewer and a soil - builder. Covering the land with grass is nature's way of restoring to old, worn-out land the fertility and good tilth characteristic of virgin soil. The true grasses do not add nitrogen to the soil, as do clover, alfalfa and other legume crops, yet the grasses are, in a sense, nitrogen-gatherers, in that the nitrogen of the soil is collected and stored up in their roots. Thus, grasses prevent the waste of nitrogen and other plant-food elements and serve to protect the soil and to maintain its fertility. By their extensive and deep-penetrating root systems, many grasses also tend to break up and deepen the soil, gathering and storing plant food in the roots and thus actually increasing the available plant-food content.
The legume crops, such as clover and alfalfa, not only accomplish all that grasses may accom plish, as described above, but also actually in crease the total and available supply of nitrogen in the soil. By means of the bacteria which grow on the roots of legume plants, free nitrogen taken from the air in the soil is made available for the use of the plant, and not only may large yields of forage rich in nitrogen and protein be taken from land planted with legume crops, but by the great root-growth and the accumulation of humus by these crops the nitrogen of the soil is actually increased. Moreover, perennial legumes, such as clover and alfalfa, are very deep feeders ; thus a part of the mineral elements of plant food required by these crops is taken from depths in the soil below the feeding-ground of ordinary crops, and by the large root-growth in the surface soil there may be accumulated a supply of the mineral elements of plant-food which gradually becomes available, as the roots decay, to crops which follow the legume crops.
When the wild prairie is first broken, the soil is mellow, moist and rich, producing abundant crops. After a few years of continu ous grain-cropping and cultivation, the physi cal condition of the soil changes—the soil grains become finer, the soil becomes more compact and heavier to handle ; it dries out quicker than it used to, and often turns over in hard clods and lumps when plowed. The perfect tilth and freedom from clods, so char acteristic of virgin soils, is al,k ays more or less completely restored when land has been laid down to grass for a sufficient length of time.