CHAPTER XXXVII 



HOW TO KEEP THE SOU. IN CONDITION TO SUPPLY THE 

 NEEDS OP PLANTS 



Now that we know something about the needs of 

 plants and the work they do, we are ready to consider what 

 may be done not only to produce good crops, but to insure 

 the production of good crops in the future. 



One thing to be considered is tillage. This is of two 

 kinds: the breaking up or the plowing in preparation 

 for the seed, and the cultivation of the soil when the crop 

 is growing. The plowing may be done in the fall or spring. 

 Can you think of any advantages of fall plowing ? What 

 is the effect of freezing on the soil ? There may be some 

 disadvantages in fall plowing in some localities. Where 

 there is a subsoil of sand, heavy rains may wash out or 

 leach from the soil some of the soluble compounds that 

 with the spring plowing might have been saved for the 

 plants. One of the most important things to think about 

 in tillage is the preparation of the seed bed, so that it may 

 be fine and fit for the seeds. 



Experiment. — Plant some corn seeds in a pot contain- 

 ing coarse, lumpy soil. In another plant seeds containing 

 the same kind of soil that has been made fine. Water 

 both. In which do the seeds germinate first? Which 

 plants thrive best after germination? 



What are some of the other benefits due to tillage ? It 

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