Read CHAPTER VII - GRASS SODS of Crops and Methods for Soil Improvement , free online book, by Alva Agee, on ReadCentral.com.

Value of Sods. - The character of the sods is a faithful index of the condition of the soil in any region adapted to grass. The value of heavy sods to a soil cannot be overestimated. They not only give to a farm a prosperous appearance, but our country’s agriculture would be on a much safer basis if heavy coverings of grass were more universal. We do not hold the legumes in too high esteem, but the emphasis placed upon their ability to appropriate nitrogen from the air has caused some land-owners to fail in appreciation of the aid to soil fertility that may be rendered by the grasses. One often hears the statement that they can add nothing to the soil, and this is serious error. They add all that may be given in the clovers, excepting nitrogen only, and that is only one element of plant-food, important though it be. A great part of the value of clover lies in its ability to supply organic matter to the soil and to improve physical condition by its net-work of roots. Heavy grass sods furnish a vast amount of organic matter which not only supplies available plant-food to succeeding crops, but in its decay affects the availability of some part of the stores of potential fertility in the land.

Prejudice against Timothy. - Timothy, among the grasses, is especially in disrepute as a soil-builder, and yet its value is great. The belief that timothy is hard on land is based upon observation of bad treatment of this grass. There is a common custom of seeding land down to timothy when it ceases to have sufficient available plant-food for a profitable tilled crop, and usually this is the third year after a sod has been broken. The seeding is made with a grain crop that needs all the commercial fertilizer that may chance to be used. Clover may be seeded also, and on a majority of farms it fails to thrive when sown. If clover does grow, the succeeding crop of timothy may be heavy. If clover does not grow, the timothy is not so heavy. The seeding to grass is made partly because a tilled crop would not pay, and partly because a hay crop is needed. It comes in where other crops cannot come with profit, and it produces fairly well, or very well, the first year it occupies the ground by itself. With little or no aid from manure or commercial fertilizer, it adds much to the supply of organic matter in the soil, and it produces a hay crop that may be made into manure or converted into cash.

If the sod were broken the following spring, giving to the soil all the after-math and the mass of roots, its reputation with us would be far better than it is. This would be true even if it had received little fertilizer when seeded or during its existence as a sod, not taking into account any manure spread upon it during the winter previous to its breaking for corn. But the rule is not to break a grass sod when it is fairly heavy. The years of mowing are arranged in the crop-rotation to provide for as many harvests as promise immediate profit. On some land this is two years, and not infrequently it is three. Where farms are difficult of tillage, it is a common practice to let timothy stand until the sod is so thin that the yield of hay is hardly worth the cost of harvesting. Then the thin remnant of sod is broken for corn or other grain, and the poor physical condition of the soil and the low state of available fertility lead to the assertion that timothy is hard on the soil. This is a fair statement of the treatment of this plant on most farms.

Object of Sods. - The land’s share of its products cannot be disregarded without loss. The legumes and grasses come into the crop-rotation primarily to raise the percentage of organic matter that the land may appropriate to itself within the rotation. Some of the crops usually are for sale from the farm. Most of the crops require tillage, and that is exhaustive of the store of humus. A portion of the time within the rotation belongs to a crop that increases the supply of vegetable matter, unless manure is brought from an outside source. Sods lend themselves well to this purpose because they afford some income, in pasturage or hay, while filling the soil with vegetation. The tendency is to forget the primary purpose of sods in the scheme, and to ignore the requirement of land respecting a due share of what it produces. Attention centers upon the product that may be removed. The portion of the farm reduced in productive power for the moment goes to grass, while the labor and fertilizers are concentrated upon the fields that are broken for grain and vegetables. The removal of all the crop at harvest, and probably the pasturing of after-math, are the only matters of interest that the fields, depleted by cultivation and seeded down to grass, have for the owner until the poor hay yield and the need of a sod for corn draw attention again to them.

Seeding with Small Grain. - The usual custom is to sow grasses with small grain, and there is much to commend it. The cost of preparing the seed-bed rests upon the grain crop, and the conditions are favorable to fall growth and winter protection, if the seeding is made in the fall. Wheat and rye are good crops with which to seed. In the case of fertile land there is the danger that the timothy will establish itself too well in a warm, moist autumn to permit clover to get a foothold the following spring, and clover should always be seeded for the sake of fertility. In northern latitudes clover cannot be seeded successfully as late in the season as wheat should be sown, as it fails to become well rooted for winter. The overcrowding of clover by timothy is met in part by reduction in amount of timothy seed sown with the wheat.

The oat crop is less satisfactory for seedings to grass and clover. The leaves near the ground are too thick, shading the young plants unduly, and the late harvest exposes the grass and clover when the season is hot, and usually dry. Some reduction in the amount of seed oats used per acre helps to save from injury.

Seeding in Rye. - When thin land is desired for pasture, and available fertility cannot well be applied, a sod may be formed more surely by seeding with rye, using the rye for pasture and a mulch, than, probably, in any other way. The ground should have good tillage and then be seeded to rye in September at the rate of six pecks of seed per acre. Timothy and red-top should be seeded with it, and in the spring red and alsike clover should be added. Whenever the ground is dry enough in the spring to permit the tramping of cattle without injury, the rye should be pastured, and preferably by a sufficient number of animals to hold the rye well in check. When the usual time for heading comes, all stock should be removed, and when heads do appear, the growth should be clipped with a mower and left as a mulch on the surface. A second clipping will be required later, with cutter-bar tilted well upward. When the usual summer drouth is past, livestock can again be turned into the field. This method is suggested only for thin fields that have failed to make catches of grass, and that for some reason cannot well be given the fertility that all thin soils need. The application of lime before seeding to the rye is an expense that usually must be met in the case of such fields, and fertilizers should be used.

Good Soil Conditions. - When the grasses and clovers desired for a sod are sown with small grain, there is competition between them and the grain crop for fertility, moisture, and light. The grain crop is the one that will produce the income the following summer, and naturally is given right of way. The amount of seed is used that experience teaches is best for a maximum yield of grain. Usually this gives a thicker stand of plants than is best for the tiny grass and clover plants that often are struggling for existence down under the taller grain. If the farmer could see his way clear to cut down the quantity of seed wheat or oats used on a fertile soil, the catch of grass would be better, but the small-grain crop is not very profitable at the best, and the owner does not like deliberately to limit it.

A greater amount of failure is due to an inadequate supply of fertility. The grass does not suffer so much from over-shading as it does from starvation, both during the growth of the grain and after harvest. The stronger grain plants appropriate the scanty stock of available fertility, and leave the grass and clover nearly helpless. This condition is especially noticeable in dry seasons when there is less opportunity to obtain food in solution. Plants which are expected in another season to fill the ground with vegetable matter are starved in the beginning and die. Plant-food is needed, and should be mixed with the soil when the seeding is made. The fertilizer needs are discussed in another chapter.

When manure is available, it should be spread on the plowed ground and mixed with the surface soil. If a soil is thin, or heavy, or light, the use of a ton of manure in this way can bring greater returns than under any other circumstances in general farming. It supplies some fertility, and it puts the surface soil into good physical condition for young plants. Land deficient in humus forms a crust after a rain, and a tiny plant suffers. A light dressing of manure, well mixed with the soil, tends to prevent this hardening of the surface and loss of water. There is no other form of fertility that can fully replace manure, for either compact or leachy land.

The probable need of lime has been discussed in other chapters. Clovers and the grasses want an alkaline soil, and there is waste of money and time in seeding acid land. The lime and the manure must not be mixed together in the air, but both can be used when fitting land for seeding, and both should be used if the need exists. One should be applied early and be well disked into the soil, and then the other application may be made and covered with the harrow. The soil is an absorbent, and the contact of manure and lime within the soil only leads to immediate availability, which is desirable in giving the grass a start.