CHAPTEE H. 



Origin of Soil, Clay, Chalk or Marl, Sand. Fertile Soil. Condi- 

 tions Influencing Fertility. "Condition or Heart.'' Func- 

 tion of Vegetable Matter in the Soil. Moisture. Mineral 

 Plant-food. Analysis of Soils. Nitrogenous Plant food. 

 Nitrification. Leguminous Crops and Nitrogen. Root-nod- 

 ules. Retention of Plant-foods by Soils. Drainage. 



IN practical agriculture the first thing to be con- 

 sidered is the soil, for on the nature of the soil 

 will depend the kind of crops which can be grown, 

 and whether the undertaking will prove remunera- 

 tive. 



Soils have their origin in the decomposition of 

 rocks, and will differ in composition and character 

 according to the nature of the rocks from which 

 they are derived. A cursory glance in almost any 

 country will show soils in process of formation ; the 

 rocks exposed and supporting a scanty vegetation, 

 the roots of which, penetrating the small fissures, 

 tend to enlarge them, while the whole plant causes 

 soil to accumulate by preventing the rain and wind 

 from removing the finer particles, to which the 

 action of the weather, amongst other things, gives 

 rise. On the death of the plant its decaying remains 

 increase the amount of soil and render the spot 

 capable of supporting a much more vigorous growth 

 of plants ; and this combined action of weather and 

 vegetation goes on till often a very considerable 



