The First Book of Farming. C. L. Goodrich
Sand is light in color, moist, coarse, not sticky, settles quickly in water, and will not burn.
Clay is darker in color, moist, very fine, quite sticky, settles slowly in water, and will not burn.
Leaf mould or humus is very dark in color, moist, very fine, slightly sticky, and burns when placed in the fire.
Experiment.—We now have knowledge and means for making simple tests of soils. Repeat the last three experiments with the garden soil. We will find, perhaps, that it is dark in color and some of it burns away when placed in the fire, therefore it contains organic matter or decaying vegetable matter or humus, as it is called. This sample has perhaps fine particles and coarse particles; part of it will settle quickly in water while part settles very slowly, and it is sticky. Therefore we conclude that there are both clay and sand in it. If we shake a sample of it in a bottle of water and let it settle for several days, we can tell roughly from the layers of soil in the bottom of the bottle the relative amounts of sand and clay in the soil. Also if we weigh a sample before and after burning we can tell roughly the amount of organic matter in the soil. Test a number of soils and determine roughly the proportions of sand, clay and organic matter in them.
Experiment.—Take the pans of soil used in our first soil experiment and separate the soils in the pans into two parts by a trench across the centre on the pan. Now wet the soil in one side of the pan and stir it with a stick or a spoon, carefully smooth the surface of the soil in the other side of the pan and pour or sprinkle some water on it, but do not stir it. Set the pans aside till the soils are dry. This drying may take several days and in the meantime we will study the classification of soils.
FIG. 16.
To show that roots need air. Bottle A was supplied with fresh water, and bottle B with water that had been boiled to drive the air out and then cooled.ToList
FIG. 17.
Bottle A contains fresh water, bottle B contains boiled water. Notice the air bubbles in bottle A.ToList
FIG. 18.
Tumblers A and C contained moist sand, B and D contained puddled clay. Cuttings in B and D died, because there was not sufficient ventilation in the clay for root-development.ToList
CLASSIFICATION OF SOILS
Soil materials and soils are classified as follows:
Stones.—Coarse, irregular or rounded rock fragments or pieces of rock.
Gravel.—Coarse fragments and pebbles ranging in size from several inches in diameter down to ½5 inch.
Sand.—Soil particles ranging from ½5 of an inch down to ⅕00 of an inch in diameter. Sand is divided into several grades or sizes.
Coarse sand ½5 to ⅕0 of an inch.
Medium sand ⅕0 to 1/100 of an inch.
Fine sand 1/100 to ½50 of an inch.
Very fine sand ½50 to ⅕00 of an inch.
These grades of sand correspond very nearly with the grains of granulated and soft sugar and fine table salt.
Silt.—Fine soil particles ranging from ⅕00 to ⅕000 of an inch in diameter. It feels very fine and smooth when rubbed between the fingers, especially when moist. A good illustration of silt is the silicon used for cleaning knives, a small amount of which can be obtained at most any grocery store. By rubbing some of this between the fingers, both dry and wet, one can get a fair idea of how a silty soil should feel. Silt when wet is sticky like clay.
Clay.—The finest of rock particles,⅕000 to ½50000 of an inch in diameter, too small to imagine. Clay when wet is very soft, slippery and very sticky. Yellow ochre and whiting from the paint shop are good illustrations of clay.
Humus, or decaying vegetable and animal matter. This is dark brown or almost black in color—decaying leaves and woods soil are examples.
Soils composed of the above materials:
Sands or Sandy Soils.—These soils are mixtures of the different grades of sand and small amounts of silt, clay and organic matter. They are light, loose and easy to work. They produce early crops, and are particularly adapted to early truck, fruit and bright tobacco, but are too light for general farm crops. To this class belongs the so-called Norfolk Sand. This is a coarse to medium, yellow or brown sand averaging about five-sixths sand and one-sixth silt and clay and is a typical early truck soil found all along the eastern coast of the United States.
"It is a mealy, porous, warm sand, well drained and easily cultivated. In regions where trucking forms an important part of agriculture, this soil is sought out as best adapted to the production of watermelons, canteloupes, sweet potatoes, early Irish potatoes, strawberries, early tomatoes, early peas, peppers, egg plant, rhubarb and even cabbage and cauliflower, though the latter crops produce better yields on a heavier soil."
A very similar sand in the central part of the country is called Miami Sand and, on the Pacific Coast, Fresno Sand. These names are given to these type soils by the Bureau of Soils of the United States Department of Agriculture.
Loams or Loamy Soils, consist of mixtures of the sands, silt and clay with some organic matter. The term loam is applied to a soil which, from its appearance in the field and the feeling when handled, appears to be about one-half sand and the other half silt and clay with more or less organic matter. These are naturally fine in texture and quite sticky when wet. They would be called clay by many on account of their stickiness. They are good soils for general farming and produce good grain, grass, corn, potatoes, cotton, vegetables, etc.
Sandy Loams, averaging about three-fifths sand and two-fifths silt and clay. These soils are tilled easily and are the lightest desirable soil for general farming. They are particularly adapted to corn and cotton and in some instances are used for small fruits and truck crops.
Silt Loam consists largely of silt with a small amount of sand, clay, and organic matter. These soils are some of the most difficult to till, but when well drained they are with careful management good general farming soils, producing good corn, wheat, oats, potatoes, alfalfa and fair cotton.
Clay Loams.—These soils contain more clay than the silt loams. They are stiff, sticky soils, and some of them are difficult to till. They are generally considered the strongest soils for general farming. They are particularly adapted to wheat, hay, corn and grass.
Gravelly loams are from one-fourth to two-thirds coarse grained; the remaining fine soil may be sandy loam, silt or clay loam. They are adapted to various crops according to the character of the fine soil. Some of them are best planted to fruit and forest.
Stony Loam.—Like the gravelly loam the stony loams are one-fourth to three-fourths sandy, silty or clay loam, the remainder being rock fragments of larger size than the gravel. These fragments are sometimes rough and irregular and sometimes rounded. The stones interfere seriously with tillage, and naturally the soils are best planted with forest or fruit.
Clay Soils.—Clay soils are mixtures of sand, silt, clay and humus, the clay existing in quite large