17 



FERTILIZERS AND MANURES. 



By D. E. Nicholson. 



Though aware that this subject is unlimited, and a large one to 

 compress into a short essay, I thought, however, that it had an 

 advantage, in affecting all branches of gardening. I propose to give a 

 short description of the different values and advantages of the common 

 fertiUzers in use, both artificial and natural. Now it is only during 

 the last century that the real use and value of manures have been 

 found out. The original phrase " to manure " meant to cultivate 

 the soil, thereby increasing its fertiUty, and this, of course, is the 

 present object of using manures. The meaning then narrowed down 

 to the application of lime, marl, or clay, and is now confined to the 

 adding of substances which contain plant-food, such as farmyard 

 manure and the ordinary chemical fertilizers. I should hke to mention 

 here that I have not dealt with any of the compounded horticultural 

 manures, a good many of which are sold at excessive prices. 



FertiUty of the Soil. — ^Nearly all soils contain sufficient stores of 

 plant-food to last several crops, but the fertility cannot be estimated by 

 the amount of plant-food present alone, but also, and principally, by the 

 amount in an available condition. Moreover, of the elements necessary 

 to plant life, all except three are available in sufficient quantities for 

 healthy growth, in most soils at least. These three are nitrogen, 

 phosphates, and potash, the latter, however, being less often required 

 than the other two. Thus, in order to get profitable returns, some 

 fertilizer is very often required, which provides to the crop these 

 three elements in an available form. Moreover, it is of httle use to 

 provide two out of the three, and leave out the third, if it is lacking. 



Besides the improvement of the chemical composition of the soil, 

 the mechanical condition must receive attention, and if the soil is 

 very sandy or clayey it will probably require some form of humus 

 to be added, in the former case to increase the water-content of the 

 soil and hold it together, in the latter case to render it more porous 

 and workable. Some form of lime is also necessary on some soils 

 to help render the plant-food available, and on clayey soils to render 

 them less sticky. 



Absorption of Nutriment. — On analysing the component parts of 

 a plant it is found that water constitutes most of the plant, the per- 

 centage, of course, varying greatly, the rest being made up of com- 

 pounds of carbon with oxygen and hydrogen. Carbon constitutes 

 about half the dry matter, and oxygen and hydrogen most of the 

 remainder, together with a few other elements in small quantities. 



