14 



THE TEMPERATURE OF THE SOIL. 



The temperature of a soil depends very much upou its humidity, dry 

 lands absorbing' more quickly and losing more slowly the heat than 

 wet lauds. The temperature of drained lands is consequently higher 

 in summer than those which are undrained. The greatest difference 

 occurs in the spring between the temperature of the atmosphere and 

 that of the soil, as, owing 1 to the moisture from the winter and spring 

 storms, the soil, in consequence of the evaporation required to dry it 

 sufficiently, but gradually acquires the proper temperature demanded 

 by the coming vegetation. After it is once thoroughly warmed it re- 

 tains a certain amount in reserve which is of benefit to the late ripen- 

 ing and gathering of certain crops. Dark colored soils absorb heat 

 more rapidly than those of lighter color.* 



FERTILITY OF THE SOIL DEPENDS ON CLIMATIC CONDITIONS. 



In this country the soils are fertile enough, for the most part, to raise 

 any crop desired, if the climatic conditions are favorable, and this is a 

 point that must not be lost sight of. As it is certain that the range of 

 the thermometer during the growing season of the year will affect the 

 productiveness of the ground, noth withstanding a favorable compo- 

 sition and texture of the soil and an adequate rainfall, and disregard 

 of such local conditions as temperature, rainfall, elevation above sea 

 level, aspect, nearness to water, &c., will lead to very erroneous opin- 

 ions of the soil. Thus, in the case of the Northwest, for example, with 

 the severe winters and late springs and early falls, only such crops as 

 will mature early can be raised, notwithstanding the noted fertility of 

 its soil. 



The amount of rainfall and the season of its descent determine the 

 nature of the crops raised, and exercise a considerable influence on the 

 fertility of the soil. The action of the rain carries the soluble ingredi- 

 ents which the plants require to their roots and supplies them with 

 the necessary moisture. The soil, however, must be permeable enough 

 to let the excess of water drain away; water-logged soils show imme- 

 diate improvement when properly drained. 



THE BARENNESS OF SOIL. 



No soil is absolutely barren unless it contains substances poisonous to 

 plants, such as an excess of organic acids, alkaline salts, the sulphate of 

 iron, the sulphide of iron, or other injurious ingredients; but it may be so 

 considered when it will not produce such crops as the farmer may wish to 

 raise. Such a soil may, in many cases, be made productive by adding 

 to it the constituent of which it is in need ; but, if this cannot be done ex- 

 cept at a prohibitory cost, or one at which, more fertile ground can be 

 procured, the soil may be regarded as practically worthless. 



* The Soil of the Farm. 



