Soil improvement

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  • Microbial biomass formation on root surfaces can be measured in plants growing in solution with or without an inert solid support. Carbon flow to the biomass can be measured by growing plants in solution or soil on a continuous source of 14C02 and the expected biomass formation predicted. The lack of correlation between measured and predicted biomass can be explained by oligotrophic growth of the micro-organisms.

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  • The large amount of water required for the production of plant substance is taken from the soil by the roots. Leaves and stems do not absorb appreciable quantities of water. The scanty rainfall of dry-farm districts or the more abundant precipitation of humid regions must, therefore, be made to enter the soil in such a manner as to be readily available as soil-moisture to the roots at the right periods of plant growth. In humid countries, the rain that falls during the growing season is looked upon, and very properly, as the really effective factor in the production of large...

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  • All plants when carefully burned leave a portion of ash, ranging widely in quantity, averaging about 5 per cent, and often exceeding 10 per cent of the dry weight of the plant. This plant ash represents inorganic substances taken from the soil by the roots. In addition, the nitrogen of plants, averaging about 2 per cent and often amounting to 4 per cent, which, in burning, passes off in gaseous form, is also usually taken from the soil by the plant roots. A comparatively large quantity of the plant is, therefore, drawn directly from the soil. Among the ash...

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  • Important as is the rainfall in making dry-farming successful, it is not more so than the soils of the dry-farms. On a shallow soil, or on one penetrated with gravel streaks, crop failures are probable even under a large rainfall; but a deep soil of uniform texture, unbroken by gravel or hardpan, in which much water may be stored, and which furnishes also an abundance of feeding space for the roots, will yield large crops even under a very small rainfall. Likewise, an infertile soil, though it be deep, and under a large precipitation, cannot be depended on for...

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  • As will be seen by referring to the analyses of soils[Pg 156] on p. 72, they may be deficient in certain ingredients, which it is the object of mineral manures to supply. These we will take up in order, and endeavor to show in a simple manner the best means of managing them in practical farming. ALKALIES. POTASH. Do all soils contain a sufficient amount of potash? How may its deficiency have been caused? How may its absence be detected? Does barn-yard manure contain sufficient potash to supply its deficiency in worn-out soils? Potash is often deficient in the...

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  • In the foregoing section, we have studied the character of plants and the laws which govern their growth. We learned that one necessary condition for growth is a fertile soil, and therefore we will examine the nature of different soils, in order that we may understand the relations between them and plants. What is a fixed character of

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  • Describe the Mapes plow. Why is the motion in the soil of one and a half inches sufficient? How does the oxidation of the particles of the soil resemble the rusting of cannon balls in a pile? The sub-soil plow is an implement differing in figure from the surface plow. It does not turn a furrow, but merely runs through the subsoil like a mole—loosening and making it finer by lifting, but allowing it to fall back and occupy its former place. It usually follows the surface plow, entering the soil to the depth of from twelve to eighteen...

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  • What is the first office of the soil? How does it hold water for the uses of the plant? How does it obtain a part of its moisture? The mechanical character of the soil is well understood from preceding remarks, and the learner knows that there are many offices to be performed by the soil aside from the feeding of plants. 1. It admits the roots of plants, and holds them in their position. 2. By a sponge-like action, it holds water for the uses of the plant. 3. It absorbs moisture from the atmosphere to supply the demands...

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  • The word soil occurs many times in this little book. In agriculture this word is used to describe the thin layer of surface earth that, like some great blanket, is tucked around the wrinkled and age-beaten form of our globe. The harder and colder earth under this surface layer is called the subsoil. It should be noted, however, that in waterless and sun-dried regions there seems little difference between the soil and the subsoil. Plants, insects, birds, beasts, men,—all alike are fed on what grows in this thin layer of soil. If some wild flood in sudden wrath could...

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  • The progress that a nation is making can with reasonable accuracy be measured by the kind of live stock it raises. The general rule is, poor stock, poor people. All the prosperous nations of the globe, especially the grain-growing nations, get a large share of their wealth from raising improved stock. The stock bred by these nations is now, however, very different from the stock raised by the same nations years ago. As soon as man began to progress in the art of agriculture he became dissatisfied with inferior stock. He therefore bent his energies to raise the standard...

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  • Soil fertility describes soil nutrient status and the factors controlling the supply of nutrients to plants. Continued efforts to improve soil fertility are required to support the world's growing demand for food, fiber, and renewable fuels. Important ecological services provided by soils, such as biodiversity, buffering capacity, and nutrient recycling benefit from the amendments applied to sustain soil fertility. Those amendments need to be applied in a manner that is both economical and practical for the producer to achieve agronomic objectives that are environmentally sound.

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  • You have perhaps observed the regularity of arrangement in the twigs and branches of trees. Now pull up the roots of a plant, as, for example, sheep sorrel, Jimson weed, or some other plant. Note the branching of the roots. In these there is no such regularity as is seen in the twig. Trace the rootlets to their finest tips. How small, slender, and delicate they are! Still we do not see the finest of them, for in taking the plant from the ground we tore the most delicate away. In order to see the real construction of a...

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  • It will be recollected that, in addition to its mineral portions, the soil contains organic matter in varied quantities. It may be fertile with but one and a half per cent. of organic matter, and some peaty soils contain more than fifty per cent. or more than one half of the whole. The precise amount necessary cannot be fixed at any particular sum; perhaps five parts in a hundred would be as good a quantity as could be recommended. The soil obtains its organic matter in two ways. First, by the decay of roots and dead plants, also of...

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  • This book on conservation and improvement of the forest soil is intended for students at agricultural universities who specialise in soil improvement and for all readers who are interested in conservation of the forest environment. The development of human society largely depends on the exploitation of the biosphere. Unfortunately, its resources cannot last forever: some may diminish, others may be irreversibly damaged or destroyed.

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  • With the vast and ever increasing demands made upon materials which are the products of cultivated fields, for food, for apparel, for furnishings and for cordage, better soil management must grow more important as populations multiply.

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  • The work of the dry-farmer is only half done when the soil has been properly prepared, by deep plowing, cultivation, fallowing, for the planting of the crop. The choice of the crop, its proper seeding, and its correct care and harvesting are as important as rational soil treatment in the successful pursuit of dry-farming. It is true that in general the kinds of crops ordinarily cultivated in humid regions are grown also on arid lands, but varieties especially adapted to the prevailing dry-farm conditions must be used if any certainty of harvest is desired. Plants possess a marvelous power...

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  • The demonstration in the last chapter that the water which falls as rain or snow may be stored in the soil for the use of plants is of first importance in dry-farming, for it makes the farmer independent, in a large measure, of the distribution of the rainfall. The dry-farmer who goes into the summer with a soil well stored with water cares little whether summer rains come or not, for he knows that his crops will mature in spite of external drouth. In fact, as will be shown later, in many dry-farm sections where the summer rains are...

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  • The object of cultivating the soil is to raise from it a crop of plants. In order to cultivate with economy, we must raise the largest possible quantity with the least expense, and without permanent injury to the soil. Before this can be done we must study the character of plants, and learn their exact composition. They are not created by a mysterious power, they are merely made up of matters already in existence. They take up water containing food and other mat[Pg 12]ters, and discharge from their roots those substances that are not required for their growth. ...

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  • One of the most remarkable agricultural practices adopted by any civilized people is the centuries-long and well nigh universal conservation and utilization of all human waste in China, Korea and Japan, turning it to marvelous account in the maintenance of soil fertility and in the production of food. To understand this evolution it must be recognized that mineral fertilizers so extensively employed in modern western agriculture, like the extensive use of mineral coal, had been a physical impossibility to all people alike until within very recent years.

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  • How does the growth of clover, etc., affect the soil? It will be recollected that, in addition to its mineral portions, the soil contains organic matter in varied quantities. It may be fertile with but one and a half per cent. of organic matter, and some peaty soils contain more than fifty per cent. or more than one half of the whole. The precise amount necessary cannot be fixed at any particular sum; perhaps five parts in a hundred would be as good a quantity as could be recommended. The soil obtains its organic matter in two ways. First, by the...

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