manent roots about one and a half inches below the surface. Blossoming, Tuber Formation, and Hilling.— Potatoes are hilled about the time they come into bloom, and this is the time that tuber formation is beginning. The ancestral type of potato developed seed about this time and died; the tendency acquired by cultivation is to throw all the reserve material into tuber production. These reproductive processes cause a severe drain upon the plant's energies, and the fortnight immediately following the blossoming period is therefore a peculiarly critical time for the plant, during which time its life hangs in the balance. At this time it is subject to extreme heat, and may be injured; also insects, fungi, etc., may attack it, and, to add to its troubles, cutting off a lot of its roots, either just before or about this time, is no doubt the common cause of a decline from which the plant never recovers. Even tuber formation, without the influence of other agencies, may cause a plant to die. The importance of studying the condition of the plant at this time will be appreciated when it is remembered that the entire crop of salable tubers is formed after this critical period is past, and full success with the crop depends upon retaining the plant healthy for from one to three months after the blossoming period. During August, in one case,' the crop of potatoes increased at the rate of over 50 bushels, or over 3,000 pounds, weekly per acre. The importance of avoiding checking growth preparatory to or during such a time is evident. 1 Ver. Bul. 72, p. 5. CHAPTER III SOILS THE soil considered best is a \deep, mellow, freeworking loam,) grading either to a sandy loam or clay loam, although the crop may be raised on lighter or heavier soils, provided the latter are drained. Tile drainage should be resorted to, if necessary, to reduce the water table to from 3 feet 6 inches to 4 feet below the surface. Some reasons for selecting a light, sandy, or gravelly loam for the crop are : 1. Such soils can be worked early in spring, and gotten ready for early planting, if desired ; 2. The lighter soil becomes warm more readily in the spring than a heavier soil, and germination of the tuber and growth of the plant proceeds more rapidly; 3. They can be easily worked, and placed and maintained in good tilth without a heavy labor bill; 4. The effects of the manures and fertilizers applied are generally perceptible for a longer period of time than on lighter soils; 5. The potatoes grown on such a soil usually come out bright and clean, smooth and of more uniform size-important factors when they go on the market; 6. Light soils usually produce potatoes of better quality, because they tend to shorten the growing period by cutting off the moisture supply, and thus forcing the potatoes to mature earlier; 7. Those grown on well-drained sandy loam soils usually keep better than those grown on stiff clay soils. Aroostock County, Maine, is famous for its potatoes.1 Its soil presents a gently rolling surface, and is composed essentially of drift deposited during the melting of the ice after the ice age, and resting on a stratum of limestone, which in many places comes to the surface. The soil partakes of the general nature of drift containing a considerable portion of sand and the usual amount of organic matter. It is peculiarly suited to potatoes, because it does not pack after hard rains nor during periods of drouth. Its open and porous nature permits the free development of tubers and the ramification of the roots. The soil was originally covered with a growth of hard and soft woods, consisting chiefly of maple, cedar, birch, white poplar, spruce, hemlock, and pine. The forest growth was dense, and in clearing large quantities of ashes were produced, which fitted the virgin fields particularly for the production of large crops of potatoes. After a few years of cultivation, the crop-producing power of the soil showed a diminution, and to-day applications of farm manures and commercial fertilizers containing a large percentage of potash are resorted to. Analyses of Maine soils show that they are silicious, contain considerable or 1 U. S. D. A., Div. of Chemistry, Bul. 58, p. 5-8. ganic matter, and are reasonably rich in lime and magnesia, which seem to be essential constituents of a soil suited to the growth of potatoes. The potash is also in fair quantity, but not sufficient to produce maximum crops. The famous potato-growing counties of Wisconsin, Portage, Waushara, and Waupaca had over 60,000 acres in potatoes in 1899, and these are as important to the Central States as Aroostock County, Maine, is to the Eastern States. The soil is glacial drift, some of it being made up of level deposits of sand and gravel covered with a light loam. The sand is usually underdrained by a bed of coarse gravel. Sandy loams prevail. Clayey loams occupy some areas, but are not prevalent. The average yield is 100 bushels per acre. On Long Island, N. Y., the chief potato soils on the south side of the island are light silt loams underlain either by gravel or sand, while gravelly till is the main type on the northern side. The yields vary from 80 to 250 bushels per acre. The Influence of Soil on Different Varieties.— Professor Buffum,' of Wyoming Experiment Station, reported on eight varieties grown on each of two kinds of soil represented on the experiment farm. The soil and crops were treated alike. Plat is bench-land above the river, and is a deep red colluvial soil containing little humus. Plat 2 is bottom-land next the river, and is a black soil containing a large amount of humus. 1 Wyo. Bul. 32, p. 6. The figures taken collectively show the importance of selecting a soil suitable for the crop to be grown, the yield being doubled on Plat 2, while taken individually it is evident that certain varieties were better adapted to the environment than others. The question of which variety will best suit the environment must be determined by the grower. Subsoiling.-Buffum', of Wyoming, states that subsoiling may be recommended throughout that State for potatoes. The cost of subsoiling to a depth of 16 inches to 18 inches varied between $3.00 and $6.00 per acre. Hays, of Minnesota, found it to be expensive and not profitable under most conditions in that State, and that it reduced the yields of crops on land already sufficiently open and porous. In humid climates, if attempted, it is advocated that subsoiling be done in the fall, to permit the readjustment of the soil granules before springtime, so that the moisture will be able to rise upward from the subsoil, as evaporation takes 1 Wyo. Bul. 41, pp. 20. 21; Bul. 32, pp. 7, 8. 2 Minn. Bul. 68, p. 609. |