MANUEES AND FERTILIZERS. 59 



lizers upon it, although stable manure is some- 

 times used. Deep, black prairie soils of the 

 new West do not as yet need additional plant 

 food, although the time is soon coming when 

 they will. Again there are alluvial river 

 bottoms subject to annual overflows which so 

 enrich them that artificial fertilization is un- 

 necessary, for such bottoms grow large, tine 

 crops of corn year after year. In the Eastern, 

 Middle, and Southern States, however, soils 

 have become impoverished by constant crop- 

 ping, and each year enough plant food should 

 be returned to them to keep them highly pro- 

 ductiva 



It is safe to say that the only way to deter- 

 mine certainly what manure or fertilizer is 

 best suited to one's land is to experiment on it 

 on a simple, practical basis. 



Stable manure is always a standard material 

 for enriching the land, and it is suited to the 

 needs of all classes of crops and all kinds of 

 soils. Its effect is more lasting than the read- 

 ily soluble commercial fertilizer. Since 1883 

 an experiment has been in progress at the ex- 

 periment station at Purdue tJniversity to de- 

 termine how long stable manure will continue 

 to affect the yield of succeeding crops. The 

 plat set apart for this experiment has been pro- 

 ducing corn continuously since 1879. To cer- 

 tain plats in the series fresh horse manure was 



