38 PRECAUTIONS NECESSARY IN MAKING EXPERIMENTS. 



show ten or twenty fold when calculating the yields per 

 acre. 



10. All this experimental work, requiring as it does, 

 care and intelligence, should be performed by intelligent 

 men and not left to ignorant workmen. 



TIME OF APPLYING FERTILIZERS. 



Fertilizers are either broadcasted evenly all over the 

 field or drilled in ; and which of these methods is prefer- 

 able depends on conditions. As a general rule, where 

 fertilizers are used in small quantities only, they are often 

 more effective when applied with a drill, because they come 

 closer to the rows of planted crops. It must be remem- 

 bered, however, that fertilizers may produce injury when 

 coming in direct contact with the seed or the young roots 

 of plants, and this danger, of course, is greater when fertil- 

 izers are applied with the drill and at planting time, than 

 when applied broadcast and previous to planting. To 

 reduce the danger from injury when fertilizers are drilled 

 in, it is well to dilute them by mixing them with several 

 times their bulk of mellow earth. 



A useful method is to apply the mineral fertilizers, that 

 is, potash and phosphoric acid, some time before sowing or 

 planting, so that they may mix thoroughly with the soil. 

 On some soils it would even be best if the potash and phos- 

 phoric acid be applied in the fall preceding the planting. 



