684 ANNUAL REPORT OF THE Off. Doc. 



manure even at the risk of the introdiuction of disease. It were far 

 better if all land could be cared for properly, receiving its plant food 

 and physical amendmenis at correct times in a wise rotation, but 

 such conditions will never prevail universally, and hence the neces- 

 sity of modification of methods outlined for perfect conditions. 



Commercial Fertilizers. — A discussion of sources of organic ma 

 terial for improvement of soils before planting leads naturally to the 

 subject of commercial fertilizers, and as the i^ractical man should 

 plan his work ahead of the plow, we discuss further the subject of fer 

 tilization before considering that part of preparation for a crop that 

 is done with plows and harrows. 



There are two methods of employing commercial fertilizers in com- 

 mon use. One of these is based on the belief that such fertilizers can 

 be used profitably only in starting a crop, and preferably those crops 

 \vith w^hich seedings to grass are made. The other method involves 

 the use of large quantities of commercial fertilizers for the constant 

 feeding of the ijlants from seed-time till harvest. I forego the 

 pleasure of a discussion^ of this important question except so far as 

 it concerns the potato. Keeping in mind the necessity of net profit 

 from the crop, we must secure all needed plant food as cheaply as 

 possible. Most soils devoted to potato-growing, excepting now the 

 seaboard sands that produce the early market crop, are naturally 

 strong. That is to say, in tliem are stored large amounts of plani 

 food that become available slowly. The average arable soil is a 

 store-house of inert elements of plant food. Availability is secured 

 in part through the growth and decomposition of crops like clover, 

 peas, vetches, timotliy, rye, etc., and the legumes also add nitrogen 

 from the air. If a light application of commercial fertilizer of any 

 sort will put clover or peas to work to supply the need's of a subse- 

 quent cash crop, such fertilization is rational and profitable. Such 

 is the scheme of a majority of farmers, though its successful opera- 

 tion is not always apparent. There is failure oftentimes to get the 

 full manurial crop or heavy sod, and the remaining crops of the rota- 

 tion, dependent largely upon that crop or sod, are too small for best 

 profit. 



The other method involves the feeding of exery crop according to 

 its supposed needs, and necessitates an expenditure of money that a 

 majority of farmers, selling in average local markets, would regard, 

 possibly with reason, as ruinous. But tlie potato, grow^n near good 

 markets, more nearly justifies such feeding than do most staple crops. 

 Its possibilities far exceed those of the staple grains, and usually it 

 is quickly responsive to fertilizers. 



Scientists have sought a rule of universal application for the use 

 of fertilizers. It was believed for manj^ years that the composition 

 of the soil, as shown by an analysis, would indicate the kind of fer- 

 tilizer that should be used, but the theory would not stand the test 



