34 TYPES OF SOIL 



order to hasten the melting of the snow. Thio is done because in 

 such elevated situations the summers are of such short duration 

 that it is of great importance to save time in getting the ground 

 ready for the seed and having them sprout as soon as possible. 

 Gasparin in his experiments found as much as twelve to fourteen 

 degrees difference in temperature between two samples of soil 

 similarly exposed to sunlight if one of the soils was made white 

 by covering it with magnesia and the other made dark by covering 

 it with lampblack. 



The amount of heat absorbed is also affected by the composition 

 of soils and the fineness of the soil particles. Clay soils are gener- 

 ally much colder than sandy soils, but coarse rocky soils often 

 suffer from extremes of temperature. 



The matter of location or relative position is also an important 

 factor. We know from observation that the southern sides of 

 hills, walls, or other wind-breaks are generally the warmest. In 

 the vicinity of Boston farmers usually choose the southern slopes 

 of hills, even where the soil seems to be poor and gravelly, for 

 growing early vegetables. But light loose soils in such positions 

 frequently become overheated and so dry in midsummer that 

 crops growing upon them soon wither away and perish. The direc- 

 tion of the cultivation is also an important matter that should not 

 be overlooked. Experiments show that crops cultivated in beds 

 running from north to south will be more equally warmed than if 

 the beds run east and west. In very many cases it is found that 

 flat cultivation insures a more equable temperature than the oppo- 

 site arrangement. 



Farm Soils. We find that soils vary greatly in the way they 

 are made up. It is obvious that different kinds of rocks in their 

 decay make different kinds of soil. The principal types of soil are 

 as follows: 



1. Sandy Soils 



Classes with reference to constituents 



2. Clay Soils 



3. Loamy Soils 



4. Limestone 



5. Buckshot Soils 



6. Vegetable Soils 



7. Alkali Soils 



