Practically all of the maturely developed soils of the Maritime Provinces are Podzols, similar to those of Scandinavia, Northern Russia and the northern parts of Quebec and Ontario. The environmental factors favouring the formation of Podzols are: abundant precipitation; long, cold winters: short, cool summers; a natural forest vegetation composed largely of coniferous trees such as pine, spruce and balsam fir. In addition, as has already been pointed out, the surface geological deposits of much of the area have been derived from sandstones or from acidic crystalline rocks such as granite. Consequently, the soils tend to be acid, leached and infertile.
The characteristics of the Podzol environment represents conditions in the Annapolis Valley. Under the dark coloured, partly decomposed forest litter which is designated as the A 0 horizon, the mineral soil is slightly darkened by an admixture of organic matter to form a shallow A 1 horizon. Below this is a white, or very light grey horizon of variable depth which is known as the A 2. These horizons constitute the portion of the soil from which the mineral nutrients such as calcium, magnesium and potassium have been leached by action of the acids released from the decomposing forest litter. Along with these, other substances, particularly the oxides of iron and aluminum are carried downward to be redeposited in the subsoil. The material left in the upper horizons, which often has the appearance of white sand, is, in fact, quite largely composed of quartz or silica (SiO 2 ), and therefore of very limited fertility.
The B horizon, or zone of accumulation, is usually reddish or brownish in color from the iron oxide which it contains. Sometimes it is somewhat compact and even cemented by iron and humus compounds.
Not only is the surface soil usually quite acid, but an acid reaction persists throughout the whole of the weathered soil profile.
It is not yet possible to present a complete regional summary of the soils of the Maritime Provinces because, to date, only five soil survey reports are available. They cover the Fredericton and Woodstock sections of the St. John Valley in New Brunswick and the Annapolis Valley, Cumberland and Colchester counties of Nova Scotia. From them some ideas of the variation in soil from place to place may be obtained.
In the Woodstock section, almost ninetenths of the area is covered by till derived from sandstones and calcareous shales or slates of Paleozoic age. On the well-drained upland areas, the soil is weathered to a depth of 18 to 24 inches. In spite of the high percentage of lime in the parent material, the surface soils are acid (pH 4.00 to 5.00) and a leached horizon 2-4 inches deep has developed. The potato is the dominant crop. By the use of large amounts of commercial fertilizer, often a ton per acre, potatoes are made to yield about one hundred barrels per acre. This is the best yield in Canada, and the adjoining section of Maine holds the record in U.S.A. The upland ridges are separated by low areas of the same material. These soils are not nearly so acid and have a much greater natural fertility but they are usually left uncleared because of poor drainage.
In the Annapolis valley, only about half the area is based upon glacial till, and water deposited materials are widespread. Moreover, both classes of material are predominantly sandy, because of their derivation from the underlying Triassic sandstones and, in spite of the fact that this type of rock contains a certain amount of calcareous cement, all parent materials of the soils are distinctly acid. The soils themselves are much more so, ranging from pH 4.00 to 5.00. It is notable that in this area, with its abundance of water-worked drift, that there are a very large number of soil types so that soils vary greatly in productive capacity even on the individual farm. As a rule, the loams and sandy loams are rated best for orchards and potatoes, while the clay loams are rated best for hay and pasture. Careful soil management is necessary, the natural fertility of the Podzols is low and the orchardists of the Annapolis Valley are nearly as heavy users of commercial fertilizers as the potato growers of the St. John Valley.
Northern Nova Scotia, as represented by Cumberland and Colchester counties, has considerable contrast in soils. The lowlands, derived in large measure from Carboniferous sandstones and shales, have typical Podzols developed under coniferous woodland. The process of leaching has affected both sands and clays and, especially in imperfectly drained areas, the grey A 2 horizon is quite pronounced.
The soils of the Cobequid uplands, on the other hand, developed from harder igneous and metamorphic rocks under mixed deciduous forest, are not so highly leached. Nevertheless, since they are shallow and stony, they are of little value for agriculture.
The soils with the greatest natural fertility in both New Brunswick and Nova Scotia are those of the river bottoms or "intervales" and of the dyked marshes bordering the headwaters of the Bay of Fundy. The fertility of the latter was thought to be inexhaustable and they have been cropped continuously for two or three centuries without the addition of fertilizer. Needless to say, they now show signs of exhaustion. Under a recently instituted program of marshland rehabilitation, dykes are being rebuilt, drainage improved and the fertility of the soil is being restored. In the past many thousands of tons of mud from the tidal flats were hauled and spread upon the upland fields of adjoining farms, but this practice is now too expensive.