The peats of the Northern Lake States are seldom cultivated because of the cost of drainage, the need for fertilizers, and the shortness of the growing season. Frost occurs every month of the year in many bogs. Most of these northern peats and mucks are likely therefore to remain indefinitely in forest or other native vegetation.

Although rocky highlands, like the Porcupine Mountains of Michigan, occupy only a small part of the region, rock outcrops and shallow soils are common. One area in Minnesota extends over nearly 3 million acres, and smaller but important areas exist in all of the three States.

Most of the exposures consist of igneous and metamorphic rocks, covered with scattered deposits of glacial drift. These rocky lands very likely will remain in wilderness, entered only by those seeking recreation, furs, or mining prospects.

Most of the upland soils of the region are podzolized, low in fertility, and usually low in organic matter. The maintenance and improvement of fertility therefore is a major concern. Control of soil erosion, essential as it is on sloping lands, generally requires less attention than the management of fertility because of the high proportion of grasses and grains in the rotation and the relatively small size and gentle slopes of most fields.

With the exception of certain areas of lime-rich soils, as in western Minnesota, liming is essential for profitable farming. Limestone is seldom available locally and is relatively expensive. Soils usually are limed with marl or sludge from paper mills. The subsoil material of "red" clays near Lake Superior may have an equivalent of 35 to 40 percent of calcium carbonate and may be excavated and applied to correct soil acidity.

THE ROTATIONS on the dairy farms in the region usually consist of small grains, hay, and pasture. The hay consists mostly of red clover and timothy mixtures, although alfalfa is adapted to many areas. Alfalfa roots penetrate into the lime layer, and stands frequently last for many years because the abundant snow cover reduces winter-killing and frost heaving. Lime and high-potash fertilizers generally are necessary to maintain productive stands. The soils in this area are relatively low in available phosphorus and potassium and particularly low in nitrogen. Remarkable responses to topdressings of nitrogen and to nitrogen, phosphate, and potash mixtures have been obtained on the older grass sods. Yields of pasture often have been doubled and tripled with the application of 10-10-10 fertilizer or similar mixtures as a topdressing.

Small grains respond well to fertilization throughout the area. Usually a complete fertilizer with a nitrogen-phosphate-potash ratio of 1-4-4, at the rate of 200 to 300 pounds an acre, applied with the seed gives the best result. When alfalfa is seeded with the small grain, additional fertilizer is usually applied broadcast before planting or topdressed on the new seeding after the grain is harvested.

ON THE LOAMY SOILS of the rolling uplands in northwestern Minnesota, the soils formed from limy parent material are less acid and do not require liming for most farm crops. These soils generally are more level and are quite productive if they are free of stones. They are low in available phosphorus, potassium, and nitrogen and require fertilization for profitable crop yields.

Many of the soils formed from limy parent materials in Marinette and Oconto Counties in Wisconsin are also neutral or only slightly acid. Magnesium deficiency often occurs because of an unbalance between calcium and magnesium in the soil. Many of these soils are also low in available phosphorus and in potassium. Magnesium sulfate or sulfate of potash-magnesia is used for a fertilizer material to restore the proper magnesium balance to the soil. The use of sulfate of potash-magnesia also adds potassium needed for good crops of alfalfa and small grains in this area.

IN THE POTATO AREAS, the soils often are heavily fertilized to produce profitable yields. The available phosphorus content of the older potato soils has been built up through fertilization to levels of as much as 150 to 300 pounds an acre. It is still necessary to apply phosphorus fertilizer on them for high yields. The available potassium and nitrogen contents almost , invariably are low, and it is necessary to apply 1 thousand to 2 thousand pounds an acre of fertilizer rich in nitrogen and potash. Small amounts of copper often are used in the fertilizer.

The soils in many of the potato areas are very acid, with a pH of 4.4 to 5.4. When the soils become more acid than pH 5.0, the soluble manganese in the soil increases and may become toxic for potatoes. The excess of available manganese can be corrected by applying 300 to 500 pounds of finely ground dolomitic limestone, which reduces the availability of the manganese without raising the pH sufficiently so that scab will become a problem. The application also increases the content of available magnesium in the soil and thus corrects a deficiency that exists in many of the soils in the areas where potatoes are grown.

POTATOES usually are grown in a 3-year rotation of oats, red clover, and potatoes. Both the oats seed and the red clover seed are harvested. All the straw and hay are left on the field to provide organic matter. The application of 20 pounds an acre of borax or fertilizer borate as a topdressing to the clover seeding after the grain has been combined in the fall of the first year has increased the production of clover seed. Most of the potato soils in this region are deficient in available boron; legumes, such as red clover or alfalfa, also need boron.

Fruit, including strawberries and raspberries, is grown in many sections. Fruits require adequate fertilization with phosphate and potash and a top-dressing of nitrogen in the spring. The berry crops are particularly adapted, because they grow best in acid soils with a high manganese content.

Some apples and cherries are produced in Wisconsin and northwestern Michigan. These fruits usually require nitrogen fertilization and quite often need potash.

The area is not well adapted to corn, but corn is grown along the southern margin of the region. Early maturing hybrids with adequate fertilization sometimes yield 70 to 100 bushels an acre. Most of the corn is used for silage. Fertilizer is particularly important to give the corn a good start in the spring. Often a plowed-down application of phosphate and potash and a sidedressing of nitrogen are needed.

Perhaps the most profitable crop to grow here for dairy farming is alfalfa, if the soils are adequately limed and fertilized. Stands can be maintained for years on the better soils if the soil is brought up to a proper level of lime and fertility and given relatively small, topdressed applications of fertilizer yearly.

DEFICIENCIES of boron, copper, magnesium, and sulfur may occur. Sulfur often is needed in north-central and northwestern Minnesota, particularly for legumes. Sulfur commonly is applied as gypsum, a hydrated calcium sulfate. Ordinary or 20-percent superphosphate contains about one-half gypsum as it is usually made, and will supply the necessary sulfur where it is used as a fertilizer.

Cobalt, a trace element not required by plants but essential for animals, is often deficient in the soils and crops in some parts of the area. Plants that grow on soils that have an adequate supply of available cobalt will take up enough cobalt so that livestock eating the feed and forage will be well supplied with it. The soils in Marinette and Oconto Counties in Wisconsin and a few other areas are low in cobalt, and cobalt deficiencies in sheep have been found. The deficiency is easily remedied by feeding salt fortified with cobalt.

The soils in some parts of the region are low in available phosphorus, and phosphorus deficiencies of livestock have been reported. The remedy is to feed calcium phosphate directly to the animal or to fertilize the crops with phosphate. The fertilization increases the phosphate contents of the crops and also increases yields.