THE PRINCIPLES OP FERTILIZER PRACTICE 495 



tlie fertilizer sold to farmers each year not only is entirely 

 wasted, but probably in some cases even becomes detrimental 

 to crop yield. 



The law of diminishing returns may be illustrated by data 

 from the Cornell University Agricultural Experiment ^ Sta- 

 tion. Floats were applied at different rates to plats receiv- 

 ing a uniform dressing of farm manure at the rate of 15 

 tons to the acre. Table CIII shows the increased yields of 

 maize due to the treatment with the rock phosphate. Pre- 

 war prices were used in the calculations. (See Fig. 60.) 



Table CIII 



Pounds op Floats 

 to the ackb 



Maize 

 (bus.) 



Maize 



(VALUE) 



FliOATS 

 (COST) 



Difference 



200 



7.0 



8.3 



10.2 



12.7 



$4.62 

 5.48 

 6.73 

 8.38 



$ .90 



1.80 



3.60 



10.80 



+$3.72 



+ 3.68 



+ 313 



2.42 



400 



800 



2400 



279. Method and time of applying fertilizers. — 

 Although considerable emphasis has been placed on the selec- 

 tion of the correct fertilizer formulae and on the adequate and 

 economical amounts to use, the method of application must 

 not be lost sight of. A fertilizer is never effective unless uni- 

 formly distributed. It should also be placed in the soil in 

 such a position that it will stimulate the plant to the best 

 advantage. 



The distribution of the fertilizer by means of machinery 

 is much more satisfactory than is broadcasting by hand, 

 as the former method gives a more uniform distribution. 

 Cereals and other crops are now usually planted with a drill 

 or a planter provided with an attachment for dropping the 

 fertilizer at the same time that the seed is sown, the fertilizer 



^Lyon, T. L., Soils and Fertilisers; p. 216; New York, 1917. 



