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FARM MANAGEMENT 



per cent in three years, if the farmer could be assured of 

 prices high enough to warrant the expense involved. 



119. Ways in which productivity may be decreased. 

 (1) The fertile surface soil may be carried away by erosion, 

 by wind, or water. Probably more soil fertility is lost in 

 this way than by cropping. This may be prevented by 

 keeping the soil in sod, by keeping cover crops on it 



FIG. 53. Yearly average yield per acre of 10 leading crops combined 

 (representing in area nearly 95 per cent of all cultivated crops) . 100 

 represents the average for the 43 years. 1 



during the winter, and by terracing the land as is done 

 in the South. 



(2) The soil may cease to hold the proper moisture 

 supply. This may be remedied by drainage and tillage, 

 and by additions of humus-making material. 



(3) The soil may cease to be favorable for the develop- 

 ment of soil organisms. This may be remedied as No. 2 

 and by the application of lime. 



1 U. S. Dept. Agr. Crop Reporter, Jan., 1911. 



