IO8 TALKS ABOUT THE SOIL. 



why and how the manure affected the soil, they did 

 not know. We know now that a plant living in the 

 soil requires all the seventeen elements, and dies or 

 grows slowly if one be absent. The three most likely 

 to be absent are nitrogen, potassium, and phosphorus ; 

 and these three are present in greater or less quanti- 

 ties in all fresh manure. It is for this reason manure 

 is the best fertilizer for all crops. It brings back to 

 the soil nitrogen, phosphorus, and potassium ; and 

 these are the very three most likely to be needed. 

 The oxygen, the carbon, and all the other elements 

 are plentiful; and by adding these three we restore 

 to the soil all the plants are ever likely to want. 

 There will be other elements in the manure ; but as 

 these are not wanted, no harm, but only good, is done. 

 One of the most curious things about this matter is, 

 that the manure from different animals differs greatly, 

 and consequently has more or less of the three ele- 

 ments. This is a matter we must examine, but we 

 must leave it till we come to our Chautauqua Talks 

 about Animals. All we have to do now is to observe 

 that the farm-manure commonly made on our farms 

 contains the three elements, nitrogen, phosphorus, 

 and potassium; and it is therefore a good fertilizer 

 for every variety of soil and every kind of crop. 



Beside this green manure from living plants, and 

 this barn and stable manure, there are many other 

 materials guano, marl, phosphatic rocks, waste matter 

 from factories and shops, bones and other remains of 

 fish and animals that contain more or less of these 



