tailieunhanh - ABSORBENTS

What substances are called absorbents? What is the most important of these? What substances are called charcoal in agriculture? How is vegetable matter rendered useful as charcoal? Before considering farther the subject of animal excrement, it is necessary to examine a class of manures known as absorbents. These comprise all matters which have the power of absorbing, or soaking up, as it were, the gases which arise from the evaporation of solid and liquid manures, and retaining them until required by plants. The most important of these is undoubtedly carbon or charcoal. CHARCOAL. Charcoal, in an agricultural sense, means all forms. | ABSORBENTS. What substances are called absorbents What is the most important of these What substances are called charcoal in agriculture How is vegetable matter rendered useful as charcoal Before considering farther the subject of animal excrement it is necessary to examine a class of manures known as absorbents. These comprise all matters which have the power of absorbing or soaking up as it were the gases which arise from the evaporation of solid and liquid manures and retaining them until required by plants. The most important of these is undoubtedly carbon or charcoal. CHARCOAL. Charcoal in an agricultural sense means all forms of carbon whether as peat muck charcoal dust from the spark-catchers of locomotives charcoal hearths river and swamp deposits leaf mould decomposed spent tanbark or sawdust etc. In short if any vegetable matter is decomposed with the partial exclusion of air so that there shall not be oxygen enough supplied to unite with all of the carbon a Pg 110 portion of its carbon remains in the exact condition to serve the purposes of charcoal. What is the first-named effect of charcoal The second Third Fourth Explain the first action. The offices performed in the soil by carbonaceous matter were fully explained in a former section p. 79 Sect. 2 and we will now examine merely its action with regard to manures. When properly applied to manures in compost it has the following effects 1. It absorbs and retains the fertilizing gases evaporating from decomposing matters. 2. It acts as a divisor thereby reducing the strength or intensity of powerful manures thus rendering them less likely to injure the roots of plants and also increases their bulk so as to prevent fire fanging in composts. 3. It in part prevents the leaching out of the soluble parts of the ash. 4. It keeps the compost moist. The first-named office of charcoal i. e. absorbing and retaining gases is one of the utmost importance. It is this quality that gives to it so high a position in the