362 MISCELLANEOUS FARM SUBJECTS 



a one-crop system on any of our fields, or at least that such a sys- 

 tem should not be continued long with annual crops. 



Certain soils deteriorate quickly through natural but obscure 

 causes, even with the best attention to cultivation. Some of the 

 reclaimed muck soils of Illinois and Wisconsin produce one or 

 two large crops of corn and then produce little or no yields unless 

 the soil is heavily manured or treated with a potash fertilizer. Some 

 of the reclaimed muck soils of California yield one or two large crops 

 of potatoes and then fail completely to produce a third successive 

 crop, although the power to produce barley is unimpaired. Flax 

 is considered one of the most exhaustive crops, as but two or three 

 successive crops can be taken from the same land, although wheat 

 will produce normal crops after the flax fails. Again, in forcing 

 vegetables and flowers in greenhouse work the soil quickly becomes 

 unable to support the continuous growth of a certain plant, in spite 

 of the liberal use of manure and fertilizers, although it may still 

 be just as well adapted to different kinds of crops. 



Soils, of course, frequently deteriorate through erosion where 

 the top soil is removed, leaving the infertile subsoil as the medium 

 of growth. Examples of this are frequently seen in the Cecil soils 

 of the Piedmont Plateau. 



HOW FERTILITY IS MAINTAINED. 



The maintaining of the productiveness of a soil means that there 

 shall be preserved within the soil sufficient quantities of soluble plant 

 food of the various kinds to produce maximum crops. To do this 

 it is not only necessary to maintain a large humus supply but the 

 soil must be kept in a good physical condition and if it is to remain 

 permanently fertile the total supplies of the various elements must 

 be maintained. We should therefore distinguish between what 

 might be termed a temporary system of agriculture in which the 

 available plant food gradually decreases, and a permanent system 

 of agriculture or that in which the available food shall be indefinitely 

 maintained. The latter point of view is the proper one for the man 

 who owns a farm of fair size, free of indebtedness. The former may 

 be better for the renter or the man who is just beginning and who 

 must pay for his land as well as support a family. It is perfectly 

 proper for a man to farm land hard until he gets started if this is 

 necessary, but he should not form the habit; and just as soon as 

 possible he should begin building up his land again so as to put it 

 into as good or better condition than he found it. The man with 

 the greatest knowledge and business ability can pay for land and 

 build it up at the same time, providing misfortune does not befall 

 him. 



Since humus may be so rapidly removed from a soil by ex- 

 haustive cropping it is highly important that a means be provided 

 for replacing it. The first essential to the maintaining of the humus 

 is the adoption of a crop rotation which shall include legume crops. 

 Even a small grain alternated with corn will maintain the humus 

 much longer than where corn is grown continuously, and where a 



