2J:4 Report on Crop Production. 



tilizcr were applied per acre tlian where only 500 and 1000 lbs. 

 were used. 



Again, the question of the after effect of heavy fertilizing with 

 purchased plant-food may well be introduced at this point. The 

 experiments now considered furnish some evidence on this point. 

 In 1901 no fertilizer was applied to Plats 6 to 10 of the Purdy 

 field, crimson clover being turned under in the fall. An influence^ 

 from fertilizers used in the three previous years is clearly indi- 

 cated, as the yield from Plats 7 to 10 was considerably larger 

 than on the check plat (No. G) and nearly as large as on Plats 

 2 to 5, which received the usual quantities of fertilizer. The after 

 effect of a chemical manure should be considered, therefore. 

 Here we are again reminded that conditions other than the sup- 

 ply of the compounds needed for growth limited the crop. 



The experiment on the Mars field should not pass unnoticed. 

 The experiment was conducted in 1900 when a fairly large crop 

 was secured, ranging from 188 to 199.8 bbls. of onions with the 

 different quantities of fertilizer. The most noteworthy fact 

 shown in this experiment is that the fertilizer, even in large 

 quantities, failed to increase the crop. The average yield on the 

 check plate was 193.7 bbls. and on the manured plats, 192.3 bbls. 



The comment of Mr. Sirrine, in immediate charge of the experi- 

 ment, was that the owner of the land " had used stable manure 

 and fertilizers in such quantities during previous years that 

 there was little need of fertilizer the present year." Certainly 

 an increase of available plant-food had no effect on the growth 

 of the crop. It is suspected that this instance illustrates a mis- 

 take in practice that is very frequently committed by farmers 

 who follow intensive farming, viz.: the use of manure on soil 

 already sufficiently charged with the available materials neces- 

 sary to plant growth. 



