Pennsylvania School of Horticulture for Women - Wise Acres Yearbook (Ambler, PA)

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There is a saying that “Lime makes the father rich and the son poor.” The cause of this impression is that frequently an abundance of potash is present in the soil in unavailable forms that lime can change to compounds that the crops can use. In time such supplies of potash would become deficient and result in diminished yields. The remedy in such a case is simply to supply the needed potash by fertilizing. Calcium cannot take the place of potassium or any other element as plant food. Clay and other heavy soils are composed of very small particles that hold water tenaciously and do not permit the movement of soil air. These conditions and the low temperature that results are unfavorable to bacterial action, the liberation of plant food, and root activity. The application of lime to such soils causes these particles to arrange themselves in groups or granules that act as if they were single larger particles. This lets in the warmth and air, favors chemical activity, and promotes bacterial action and plant growth. It also makes the soil more mellow and workable. Very sandy soils are too loose to hold moisture and fertility as well as would be desirable. On such land, lime acts as a weak binding material and makes the soils more compact and retentive. The forms of lime that will correct soil acidity and give the other beneficial results already mentioned arc quicklime, water-slaked lime, and carbonate of lime. The last may be in the form of air-slaked lime, ground limestone, or ground oyster shells. Marl is an impure carbonate of lime that may also be used. The effectiveness of any form of lime is in proportion to the amount of calcium it contains. Fifty-six pounds of quicklime are equivalent to seventy-four pounds of water-slaked lime or one hundred pounds of air-slaked lime, ground limestone or crushed oyster shells. Ground quicklime is the most active of these and the carbonated are mildest in their action. If the soil should have a superabundance of undecomposed organic matter or a large degree of acidity, the vigorous action of quick- or water-slaked lime may be desirable. These forms also have greater power to liberate food elements already in the soil. But if used in large quantities in the soils in the usual condition, they are destructive to humus. The carbonates are always safe forms to use, and if finely divided are fairly quick in their action. It is not considered advisable to use any other forms on sandy soils. Experiments conducted on heavy land over long periods of time also showed somewhat better results for the carbonate, which, in this case, was ground limestone. Where lime must be shipped a long distance, quicklime is the most economical in freight, the shipping cost being only a little more than half as much as for ground limestone, in proportion to its efficiency. If quicklime should be much cheaper than any other form, when all factors of cost in money and labor have been estimated, it may be purchased in the lump form a few months before needed, put into 5

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t!Jta filse nf tme on the Calcium is one of the elements essential to plant life. It plays an important part in the formation of the plant tissues, particularly those of the leaves and stems. A scarcity of it dwarfs plants and diminishes their hardiness. The amount present in the soil may vary from scarcely any to nearly 20 per cent. Soils that contain half of one per cent, of calcium usually have an ample supply of it in a form that plants can use. Nearly all of the compounds in which it occurs are slightly soluble in soil water, and the supply of available calcium in a given soil may be lost by leaching out. All of the chemical compounds of calcium used to improve the soil are popularly referred to as lime, though this use of the term is not accurate. Gypsum, or land plaster, does not correct soil acidity, as do the other compounds of calcium that are used on the land, and it will not be included under the term lime in this article. Lime is beneficial to the soil in several ways: As a direct fertilizer, by neutralizing acids in the soil and favoring the work of useful soil organisms, by setting free other elements of plant food already present in the soil but not available previously, and by improving the physical condition of the land. The supply of calcium as an element of plant food is ample in most soils; but it is usually much needed for its other beneficial effects. A few crops, as potatoes, tomatoes, and strawberries, prefer slightly acid soils; but most farm and garden crops thrive better in alkaline soils. This is notably true of the clovers. Newly cleared land is usually acid and newly drained swamp land is nearly always so. Most commercial fertilizers leave acid residues in the soil, and most cultivated crops remove larger amounts of bases than of acids from the soil. In all these cases of soil acidity, lime is the most satisfactory and economical corrective agent. Most soils that have been under cultivation fifty or a hundred years need lime, unless it has been applied as a fertilizer. Even soils underlaid by limestone, that have been tilled a long while, are frequently greatly benefited by liberal applications of lime. If phosphates be applied to a soil poor in available calcium, they are acted upon by other bases and changed to compounds that it is difficult for the plant to use. A liberal application of lime just before the addition of a phosphate, causes it to take a form readily available to common crops. The nitrifying bacteria, by whose agency the nitrogen of the soil air is made available to clover and related plants and is incorporated as nitrates in the soil, cannot thrive permanently where conditions are not alkaline. 4

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piles of about 300 to 400 pounds, each in slight excavations and covered a few inches deep with moist soil. If the land should be dry the lime should be moistened and the soil used to cover it should be made wet after it is piled on. Lime so treated will be slaked within ten days or two weeks and will be reduced to a finer powder than if it had been treated with a larger amount of water and exposed to the air. If now the piles be spread rather thinly and exposed to the air, they will become air slaked in a few weeks or months. There is very little lime lost by this treatment and no harm will result from the small amount of soil that will become mixed with the lime in this way. The few lumps that may be found may be removed by putting the lime through a sand screen. In doing this the workman should take advantage of the wind to keep out of the lime dust. Air-slaked lime is much less disagreeable to handle and apply to the land than quick-or water-slaked lime. Lime should not be plowed under, for it works downwards, never upwards. When it is applied to a cultivated crop, the land should first be plowed and disked or harrowed. The lime may then be put on with a fertilizer drill and will be well worked into the surface soil by subsequent preparation of the land. If it be applied to a pasture or meadow, autumn is a good time, as this allows the lime to work its way into the soil during the winter and early spring. The quantity of lime needed per acre depends upon the acidity of the soil and the frequency of applications. On newly drained swamp lands as much as three to five tons of quicklime or its equivalent may be needed, in some cases, to correct the soil acidity. On ordinary land that has been under cultivation for some time, from one to two tons of ground limestone, or its equivalent, every four years, wilj usually be ample. Test the soil occasionally with the litmus and give most of the field the treatment that you consider best; but set aside a small part of it for test plots and try various amounts and forms of lime on them, then follow on the entire field the practice that has given the best results on the plots. John L. Doan. 6