100 AGRICULTURE 



to keep a crust from forming. Compare the growth and yield of the 

 corn in the three plots. 



2. Just after you cultivate the second plot, carefully remove the soil 

 from the roots of a plant in each plot and examine them. 



3. Fill one flowerpot with wet, packed clay, and one with the same 

 kind of soil in good condition. Set in each a geranium or other plant, 

 and water and care for both in the same way. Is there any difference in 

 the growth of the two ? 



4. Examine and compare the plowing of farmers in your neighbor- 

 hood. Are straight furrows better than crooked ones? If so, why? 

 What is the disadvantage of a very wide furrow-slice? of a very 

 narrow one? Why should the furrow-slice be inverted? 



5. Compare the tools and methods used by different farmers in the 

 cultivation of the same crop. Tell which you prefer, and why. 



CROP ROTATION 



One-crop System. In many sections, as in the grain states 

 of the West and the cotton states of the South, the one-crop system 

 is practiced. Farmers rely on a certain staple for their money crop. 

 In this, all available land is planted year after year. This cropping 

 is continued as long as the land yields profitable crops often 

 longer. There are prairie farms which have been in corn thirty 

 years. Acres which once produced seventy-five bushels of grain 

 now grudgingly yield fifteen, but spring after spring sees them 

 plowed and planted again in corn. 



Generally, however, the soil will not bear this continuous crop- 

 ping, and it is left out every two or three years to ' rest,' as it is 

 called. The processes of nature to some extent restore its wasted 

 fertility, but sooner or later its crops cease to repay the labor 

 of production. Then the land is left to wash in gullies or to 

 grow up in weeds and bushes. There are thousands and thousand^ 

 of acres of this ' run down ' land in the United States, 



