420 THE HOME, FARM AND BUSINESS CYCLOPAEDIA. 



It is doubtless possible by means of rotations manured on the above 

 principles to farm successfully with the sale of all the crops produced, and 

 without the use of farmyard manure ; this is possible at least so long as 

 artificial manures can be obtained at a low price. In the majority of 

 cases, however, the special manuring will only be required to supplement 

 the general manuring by farmyard manure. Under these circumstances 

 it would seem best, from a chemical point of view, to apply the farmyard 

 manure to those crops which most require potash, or which stand most in 

 need of a general manuring ; such crops would be pasture, seeds, turnips- 

 and potatoes. 



The economic value of potash manures varies much on different soils. 

 As potassium salts are an expensive manure, the farmer should always 

 ascertain by means of small field experiments whether they will, in his 

 case, yield a remunerative result, before employing them on any large 

 scale. 



As the whole object of artificial manuring is to supplement the deficien- 

 cies of the soil, it is highly desirable that a farmer should ascertain by 

 trials in the field what is the actual amount of increase which he obtains 

 from the application of the manures he purchases. A few carefully made 

 experiments will teach him what his land and crops are really in need of. 

 Should he add superphosphate with the nitrate of sodium for his wheat ? 

 What dressing of the nitrate is most economical ? Is superphosphate 

 alone sufficient for his turnip crop, or should guano or nitrate be employed 

 as well ? What is the smallest quantitv of superphosphate sufficient for 

 the crop ? Will it pay to use potassium salts for his seeds or pasture ? 

 These and many other questions can only be answered by trials on his 

 own fields, and on the farmer's knowledge of such facts will depend the 

 economy with which he is able to use purchased manures. 



