92 Elementary Principles of Agriculture 



and unplowed through the winter has much to do with 

 the " wearing out" of the soils. A better plan would be 

 to have the ground covered by some winter annual 

 plant, such as oats, which could be grazed. 



131. Green Manuring. Sometimes crops are grown 

 with no intention of saving the above-ground portion 

 for hay, but it is plowed under to increase the content 

 of humus in the soil. While, in general, it would be 

 much better to save the hay and, after feeding to stock, 

 return the compost to the soil, there may be situations 

 where it is desirable to turn the entire crop directly 

 into the soil. When a crop is plowed under to enrich the 

 soil, sufficient time should be allowed for complete decay 

 before sowing another crop. The decaying plant remains 

 often causes the soil to become quite acid for months 

 afterward. 



132. Relation of Texture to Fertilizing. The profit or 

 loss resulting from the application of fertilizers depends 

 much on the texture of the soil. Irrigation water and 

 fertilizers are but poor and expensive substitutes for 

 timely efforts to improve the texture of the soil. The 

 best results from irrigation, or the application of ferti- 

 lizers, may be expected only when the soil is in the most 

 favorable tilth. "Tillage is manure." 



133. Experiments on Soil Testing. In <j 117, mention 

 was made of the desirability of testing the value of 

 various fertilizing substances for any particular soil 

 formation. Select a level piece of soil whose productive- 

 ness is to be tested under varying treatments, and lay 

 out into beds, one (or two, or more, if desired) yard 

 square. The location selected should be such as to give 

 uniform conditions in all the beds, and all should be pre- 

 pared alike. Fall-sown oats, wheat, or barley, are suitable 



