23^ 



Bulletin 241. 



In both years plat 722, which received twice the amount of acid 

 phosphate, gave a lesser increase in yield than plat 721. In 1905, 

 plat 724, which received twice the acid phosphate that plat 725 re- 

 ceived, yielded one-fourth less hay, but in 1906 yielded a some-, 

 what greater increase. This apparent depression in yield, where 

 too large a proportion of acid phosphate to nitrogen was used, 

 was further brought out by the Bureau of Soils by means of tho 

 basket method. Brown, while detailed to the Cornell Experiment 

 Station, procured soil from the untreated plat 729 of this ex- 

 periment, and treated the soil of different baskets with fertilizers 

 in the same quantities and proportions as were applied in the field 

 test. In the soil of each of these baskets he grew thirty wheat 

 plants from December 2, 1905, to January 2, 1906, when the 

 variation in green weight was determined. 



Below is given the variation in green weight representing the 

 yield on the untreated soil as 100. For comparison, the variation 

 in yield of field cured hay for the preceding and succeeding seasons 

 is given, by representing the average of the eight untreated plats 

 as 100 and adding the percentage increases to 100: 



Treatment. 



No treatment 



320 lbs. acid phosphate. 

 80 lbs. muriate potash . 

 160 lbs. nitrate soda. . . 



320 lbs. acid phosphate. 

 160 lbs. nitrate soda. . . 



320 lbs. acid phosphate. 

 80 lbs. muriate potash. . 



160 lbs. nitrate soda. . 

 80 lbs. muriate potash . 



160 lbs. nitrate soda . . . 

 80 lbs. muriate potash . 

 320 lbs. acid phosphate. 



160 lbs. nitrate soda. . . 

 80 lbs. muriate potash . 

 640 lbs. acid phosphate . 



320 lbs. nitrate soda . . . 

 80 lbs. muriate potash . 

 640 lbs. acid phosphate. 



320 lbs. nitrate soda . . . 

 80 lbs. muriate potash . , 

 320 lbs. acid phosphate . 



10 tons of manure. 

 20 tons of manure. 



Variation in Variation in Weight 



weight of 



green wheat 



by basket 



method soil 



from Plat 



729. 



100 



82 



104 



155 



127 



95 



147 



147 



142 



189 



209 

 133 

 151 



OF Field Cured Hav'in 

 Plat Experiments. 



Preceding 



season. 



1905. 



100 

 128 

 144 

 156 



173 



124 



188 



187 



165 



241 



291 

 220 

 286 



Following 



season. 



1906. 



100 

 112 

 1.36 

 151 



IC.T 



153 



173 



189 



168 



239 



225 

 158 

 249 



