42 GARDENING FOE TUB SOUTH. 



nures, not only without loss, but with decided benefit, and 

 the ammonia will be retained. 



Another indirect agency of manures is in protecting 

 plants from sudden changes of temperature. There is no 

 doubt that rich soils and those abounding in animal and 

 vegetable remains, are less liable to change their tempera- 

 ture with the incumbent atmosphere than those of poorer 

 constituents, for the decomposition of manures gives 

 warmth to the soil. Corn can be grown in high latitudes 

 upon rich land only ; upon a poor soil it would perish. 



The last indirect eifect of manures upon plants is by 

 improving the texture of the soils in which they grow. 

 Decomposing in the ground, they leave interstices as they 

 become less in bulk, making it more light and porous. 

 The effect of manure in rendering a stiff soil light and 

 friable is very well known. It is equally true that vege- 

 table manures give to sandy soils greater tenacity, ena- 

 bling them better to retain moisture and ammonia. 



Manures, then, should be adapted to soils and circum- 

 stances. Cohesive and binding manures are most suitable 

 for open sands ; those of open texture, for stiff clays ; those 

 that readily attract and retain moisture, for dry soils ; heat- 

 ing, dry, strawy, and turfy manures, for wet or clayey 

 soils ; and those of slow decomposition for hungry gravels. 



CHAPTER V. 



MANURES. THEIR SOURCES AND PREPARATION. 



Having considered the modes in which manures act up- 

 on the growth of plants, a still more important inquiry 

 remains, viz. : What manures can we obtain and render 

 available ? The scarcity of manures with us is a great dif- 

 ficulty in gardening. But a small amount of live stock is 



