248 



SOILS AND FERTILIZERS 



with fertilizers. After preparation for the crop, small 

 plots 1/20 of an acre are staked off. A convenient size 

 is, length 204 feet, width 10 feet 8 inches, area 2176 

 square feet. Between each plot a strip 3 feet wide is 

 left. The plan is to apply one element or a combina- 

 tion of elements to a plot and compare the results with 

 plots differently treated. 70 



296. Preliminary Trial. It is best to make a prelim- 

 inary trial one year and verify the conclusions the next. 

 In making the tests, eight plots are necessary and fer- 

 tilizers are applied in the following way : 



The first plot receives no fertilizer and is used as the 

 basis for comparison. 



The second plot receives a dressing of 8 pounds nitrate 

 of soda, 1 6 pounds acid phosphate, and 8 pounds sul- 

 phate or muriate of potash. 



The third plot receives nitrogen and phosphoric 

 acid. 



The fourth plot receives nitrogen and potash. 



The fifth plot receives nitrogen. 



The sixth plot receives phosphoric acid and potash. 



The seventh plot receives potash. 



The eighth plot receives phosphoric acid. 



