Alluvial soil

“ Every one is familiar with the fact that many rivers overflow their banks at certain seasons, and spread themselves out over a wide area, sometimes reaching to the foot of the hills that bound the valleys through which they flow. This is the origin of those Alluvial Plains so remarkable for their surpassing richness and fertility. In each successive year a thin film of sediment is deposited on the surface of the land; and thus in the course of ages a soil is formed capable of producing, season after season, the most luxuriant crops without manifesting any symptoms of exhaustion. ”

“ The alluvial soil, which is remarkable for its richness, frequently reaches a depth of fifteen feet and could be brought to an almost incredible degree of productiveness by the application of modern agricultural methods. ”

“ On these little rises, for they are not hills, trees grow, and grass also; but grass and weeds are the only occupants of the soil where there is no rise of ground. The soil is alluvial to greater or less depth in these barrens, though on some of the highest rises there is little or none; the lower the ground the deeper the alluvion. On these gentle rises, where there is no alluvion, we find stiff, blue clay, and no pebbles. Under the alluvial black soil, in the lower grounds, we find pebbles similar to those in the prairies, owing to similar causes. ”

“ Clay, Dense Marls, and Alluvial Soils generally, are apt to be cold and damp. Water is retained in them, and is often very impure. Thorough drainage improves a clay soil, and a house on a clay soil may be so constructed, as not to be damp.
9. Cultivated Soils are not necessarily unhealthy; but
10. Made Soils are always to be carefully avoided, as sites for houses. The materials with which inequalities have been filled up are commonly the contents of dust-bins, or some other refuse. The gradual putrefaction of organic matters renders the air about the houses impure. ”

“ Leachy Substrata.—While we may thus overcome the disadvantages of a dense subsoil or hardpan, there is another difficulty not uncommonly met with in alluvial lands, which cannot be so readily remedied. It is the occurrence, at from two to six feet depth, of coarse sand or gravel, through which capillary moisture will not ascend, but through which irrigation water will waste rapidly, leaving the overlying soil dry. Then unless very frequent irrigation can be given, the crop will suffer from drought, unless indeed the gravel itself is filled with bottom water upon which the root-ends can draw. ”

“ Lowland Tree Growth.—The variations occurring in the valleys or alluvial bottoms are less obvious to superficial observation, yet equally important and cogent to the close observer. In the properly alluvial lands, one dominant condition, that of adequate moisture supply, is almost always fulfilled, irrespective of soil quality. In addition to this, as stated in chapter 2 (see page 24) , practically all the alluvial lands of the humid region may be considered as being of a more or less calcareous character, as compared with the adjacent uplands. ”

“ The white spruce forest along the banks is most inspiring, magnificent here. Down the terraced slopes and right to the water's edge on the alluvial soil it stands in ranks. ”

“ In selecting a site, a loose, porous soil is, for obvious reasons, preferable to ground liable to be damp or wet. Pure, dry sand, and gravel, make excellent sites for building purposes. Next to these, rocky soils may be chosen, and are usually quite healthy. Clay soils, which are more or less impervious to water, and therefore always damp and chilly, and alluvial lands, must not be chosen as a site for dwellings. ”

“ The alluvial flats are covered with a luxuriant crop of grasses. But on the table lands the grass is not abundant. There has now been a year's experience of the capability of the soil, and there is no doubt that it can abundantly produce any grain, fruit, vegetable, tree, or shrub, which belongs to its parallel of latitude. The sandy loam is considered the best for present purposes, the stiff clay lands being difficult to break up, and requiring more time and labour than many are willing to bestow. ”

“ The soil, being alluvial, is in most cases easy to dig, and when the bed rock is reached it becomes an open question whether to go deeper into the decomposed rock or to be content with what supply has been struck. ”

“ Fig. 31. Wheat growing in soils supplied from below with water. All the water the plant gets has to travel upwards
Thus we shall expect great differences in the moisture of various soils. In some districts there is much more rain than in others, and therefore the soils get a larger supply of water. Sandy soils allow water to run through while a loam holds it like a sponge, in a loam also the water readily moves from wet to dry places. Further, water runs down hills and collects in low-lying hollows or valleys; here, therefore, the soil is moister than it is somewhat higher up. ”

“ Natural soils consist of substances derived from the decomposition of various kinds of rocks, the bulk consisting of clay, silica and lime, in various proportions. As regards preparation, draining is of course of the utmost importance. The ground should also be trenched to the depth of 3 ft. at least, and the deeper the better so as to bring up the subsoil—whether it be clay, sand, gravel, marl, &c.—for exposure to the weather and thus convert it from a sterile mass into a living soil teeming with bacteria. ”

“ We must again dwell on the principles already emphasized, that soils must be treated according to their nature. If too damp, they must be drained; if of the fortunate quality of a sandy loam resting on a clay subsoil, they can be abundantly deepened and enriched from the start, if of a heavy clay, inclined to be cold and wet in spring, and to bake and crack in summer, skill should aim to lighten it and remove its inertia; finally, as we have shown, a light, porous soil should be treated like a spendthrift. ”

“ That water, on undrained land, causes two evils; it stagnates and renders plants unhealthy, and it is too cool, rendering land what we call cold. Thus, the deeper you plow land, and the finer you make it, the [Pg 394] warmer it will be, and the more perfectly it will control moisture. Mixing soils by subsoiling, trenching, and deep plowing, and by carting on foreign substances, is wholly on this principle. Sand that drifts about with the wind is too light to retain moisture, and needs clay carted on. By this means the poorest white sand has often been converted into the most productive soil. ”

“ These boxes involve expense, but permit inspection and division of the flow according to the needs. They may be built of brick, stone, concrete, or even wood.
Fig. 31.—Close soils should be deeply subsoiled and underdrained. Porous, well-drained, air-filled soil is absolutely necessary. A, Subsoiled ground; B, 3 or 4 inch distribution tile; C, depth variable with the climate, 11⁄4 to 31⁄2 feet; D, 4-inch underdrain; E, depth such as would prepare land for good crop production, generally 31⁄2 to 4 feet; F, stone or other coarse material; G, gravel grading upward to coarse sand; H, loose soil. ”

“ If no spring, or ooze, keep up the supply, and if no more rain fall, the subsoil may be dried to a considerable depth, cracking and gaping open, in wide fissures, as the clay loses its water of absorption, and shrinks. After the surface soil has become sufficiently dry, the land may be plowed, seeds will germinate, and plants will grow. If there be not too much rain during the season, nor too little, the crop may be a fair one,—if the land be rich, a very good one. It is not impossible, nor even very uncommon, for such soils to produce largely, but they are always precarious. ”

“ The soils collect material rather than lose it (thus despite forming on sandy deposits they have a higher silt and clay content than the ridge top soils) leaching is absent, being young they have only a single soil horizon, and because they are regularly or temporarily water-logged they are reduced. ”

“ The warmest exposure is good for early vegetables, and the cooler and more shady for the main crop. Much can be done to regulate this by fences and buildings. They will be warm and early on one side, and cool and late on the other.
Soil.—A rich loam is always best. To convert stiff clay, or light sand and gravel, into a good loam, is an easy matter on so small a plat as is usually devoted to a garden. Draw an abundance of sand on clay-ground, plow deep and mix well, and one winter's frost will so pulverize the whole that it will be in excellent condition. ”

“ The soils upon which these successful crops are growing vary widely, both in their physical and chemical character, ranging from a light, sandy loam, with sandy subsoil, to a medium heavy clay, with compact clay subsoil, which indicates clearly that success does not depend so much upon the character of the soil as upon the methods of seeding, fertilization and after-treatment, though the most successful stands were, as a rule, obtained upon sandy soils, overlying a reasonably open subsoil. Twenty-seven growers had a more or less satisfactory experience, while 17 were absolute failures. ”

“ The field slopes towards the river, and, on the slope, the clay strata coming out to the surface, naturally bring out the water, so that the side hill was so wet as to produce cranberries—quite too wet for any hoed crop. At the foot of the hill the soil is a stiff clay, with veins of sand and gravel. Through the centre was a wet ravine, which served as a natural outlet for the springs, and which was so full of black alders as to make an excellent cover for woodcock. ”

“ In the land already under tillage it is obvious that the subsoil is covered with a soil actually in use, consisting of vegetable mould annually loosened by the spade or plough, and admitting the penetration of light, of air, and of water, to the subjacent and half decomposed matter. In the uncultivated neighbouring tracts we shall on the contrary find it covered with a thick mass of peat, the immediate soil on which the heath, the sphagnum, the carices, and the rushes alternately flourish and die, adding fresh matter to this already impenetrable substance. ”

“ It will be observed that in all cases where a crop growing on a clay soil could be compared with the same on a lighter soil, the moisture required to keep the crop in good condition was very much greater in the clay than in the loam or sandy soils. ”

“ The clay and humus soils carry crops through dry weather better because of their power to hold moisture and to absorb or soak up moisture from below. It is for this reason also that clay and peaty soils more often need draining than sandy soils.
When rain falls on a sandy soil it enters readily, but it is apt to pass rapidly down and be, to a great extent, lost in the subsoil, for the sand has not sufficient power to hold much of it. ”

“ The ease with which soils absorb, retain or lose moisture, depends mostly on their texture, humus content, physical condition, and surface slope or artificial drainage. It is to the extent that cultivation can modify these factors that more soil water can be made available to the growing crop. There are loose, open soils through which water percolates as through a sieve, and there are tight, gumbo soils which swell when the surface is moistened and become practically waterproof. Sandy soils take in water more readily than heavier soils, hence less precaution is necessary to prevent run-off. ”

“ The not inconsiderable time required for water to reach its permanent level or the country drainage in most soils, often insures the retention of a certain surplus over what the soil can permanently hold, within the period when it can be utilized by growing crops; whose roots moreover are more likely to penetrate deeply in land where there is a steady increase of moisture as they descend, than when the contrary condition is encountered. ”

“ If the water from rains is held in the surface by an impervious stratum beneath, it is idle to spend money in other amendments until the difficulty respecting drainage has been overcome. A water-logged soil is helpless. It cannot provide available plant-food, air, and warmth to plants. ”

“ But some soils are so constituted as to be of diminished value without a suitable mixture of other earths than those of which they are composed, and in such case are permanently benefited by such additions of earthy substances. If lands, for instance, are too sandy, or gravelly, the addition of clay to them, or what is better, of upland marle, will permanently improve the soil; and where these earths can be found within reasonable distance it will usually be labour well expended in making such applications. ”

“ While the physical character is of secondary importance, as generous crops are grown in sandy soil as well as in heavy loams, still the ideal soil is a sandy loam, i. e., a mixture of organic matter, clay and sand. A subsoil of gravel, or the presence of hard-pan, is not desirable, as cultivation to a depth of from twelve to fifteen inches is necessary to produce the best results. ”

“ The difference is due largely to the absence of humus. The character of the subsoil has an important bearing on the condition of the upper soil. A layer of sand or gravel a few feet below the surface provides natural drainage, but if it be too deep, it may allow the water to run away rapidly, carrying the plant food down below the roots of the plants. A hard clay subsoil will render the top too wet in rainy weather and too dry in droughts, because of the small amount of water absorbed. Such a soil is benefited by under-draining. ”