THE SOIL AND ITS IMPROVEMENT. Ill 



the soil before the lime is added. In no case should barn-yard 

 manure and lime be mixed, as loss of ammonia is certain to result. 



There is yet another manner in which lime is beneficial. 

 When vegetable matter undergoes decomposition in the soil 

 where there is an excess of water, and consequent deficiency of 

 air, certain organic acids are formed in the soil which are inju- 

 rious to vegetations. This is indicated by the growth of moss 

 and plants like red sorrel. When lime is added to a soil in this 

 condition, it combines with these acids, forming harmless com- 

 pounds. Draining such land by removing the water, and ad- 

 mitting the air, overcomes the cause of " sourness." 



GYPSUM. Land Plaster. The beneficial action of this sub- 

 stance has never been fully understood, but some recent experi- 

 ments seem to show that when sprinkled on the clover, it is ab- 

 sorbed by the leaves. If this is the fact, the benefit derived 

 from plaster probably arises from its furnishing lime to the plant 

 in a soluble form, as plaster is the most soluble of any of the or- 

 dinary compounds of lime. 



BONE MEAL. This important fertilizer is or should be simply 

 bones reduced to powder. The object of the grinding is to 

 cause the bones to undergo decomposition in the soil more rap- 

 idly. It contains all the important elements of plant food in 

 large proportion. Bones are entirely insoluble in water, but 

 when mixed in the soil with decaying vegetable matter they un- 

 dergo decomposition and are changed into available plant food. 

 The more finely they are ground the more rapidly this decompo- 

 sition proceeds. As the presence of vegetable matter is essen- 

 tial, it is found that bones act more rapidly when applied 

 to a sod. 



ROCK PHOSPHATE. In South Carolina and some other coun- 

 tries immense deposits of phosphate of lime are found. This, 

 when reduced by grinding to a fine powder, is known as rock 

 phosphate, and is valuable as a manure for the purpose of sup- 

 plying phosphoric acid. Like bones it is more rapid in its 

 action when applied to soil containing decaying vegetable mat- 

 ter, and hence is most useful on sod ground. It contains no 

 nitrogen and would seem to be best adapted to lands over-rich 



