FIELD TESTS WITH FERTILIZERS 



219 



Should good results be obtained on plot No. 3, the 

 indications are that there is a deficiency of the two 

 elements nitrogen and phosphoric acid. An increased 

 yield from No. 4 indicates deficiency of nitrogen and 

 potash. Under such conditions the use of a complete 

 fertilizer would be unnecessary. If No. 5 gives an 

 additional yield the soil is in want of nitrogen. From 

 the eight plots it will be possible to tell which of the 

 various elements it will be advisable to use. The fer- 

 tilizers should be applied after the land has been thor- 

 oughly prepared and before seeding. Corn is a good 

 crop for the first trials. The number of plots may be 

 increased by using well-prepared stable manure and 

 gypsum on plots 9 and 10 respectively. The second 

 year the results should be verified. 



280. Deficiency of Nitrogen. — If the results indi- 

 cate a deficiency of nitrogen, select two crops, one as 

 wheat which is particularly benefited by dressings of 

 nitrogen, and another as corn which has no difficulty in 

 obtaining this element. The cultivation of each crop 

 should be that which experience has shown to be the 



