PROCEEDINGS OF THE ANNUAL MEETING. 113 



less profusion or so readily obtainable that the tillers of the soil need feel 

 no anxiety. The case is different with the other three, the most precious, 

 costly, and indispensable substances, without which no form of life, vege- 

 table or animal, is possible — the tripod of agriculture and the basis of life 

 — potassium, phosphorus, and nitrogen; a silvery metal, a waxy solid, and 

 a gas. 



It is not in these separate forms that these materials are found in plants, 

 but in states of chemical combination they are found in all plants, and in 

 the absence of any one of these no form of life could exist. They are not 

 only the tripod of agriculture, but the tripod of life. They exist in only 

 small quantities in soils, are soonest exhausted by injudicious cropping, 

 and are the most costly to replace. In the majority of cases a soil is 

 exhausted by cropping by the removal of one or more of these materials 

 below the requirements for a full crop. Not only is each one of these three 

 indispensable for plant life, but a limited supply of any one will corre- 

 spondingly limit the action of all other manurial materials in the soil. To 

 accumulate in the soil and to present to the plant in active form these 

 three substances, are the essential chemical conditions of extraordinary 

 cropping. With abundant supply of these in soils of ordinary composition 

 and physical condition, there are no limits to production save those 

 imposed by physical conditions of growth — the sunshine and the rain. 



Manure. — Manure is any substance added to the soil to increase the 

 growth of plants by furnishing increased amounts of plant food. The 

 best example is barnyard or stable manure. Animal excrements have been 

 recognized from earliest times as powerfully promoting plant growth. 

 "Dig about and dung it" was the biblical prescription for an unfruitful 

 tree. Stable manure is a complete manure, as it furnishes all the mate- 

 rials for plant growth in an available form. 



I need not talk to you about the value of stable manure. The only 

 trouble is, how to get enough of it. The fruitgrower does not keep 

 enough stock to furnish the desired amount. I will, however, speak of 

 two points about stable manure. 



(1.) The quality of the manure depends largely upon the kind of food 

 fed to the stock. President Wells told me of a farmer near Constantine 

 who fed a large amount of stock for the shambles, especially sheep, buy- 

 ing grains £tnd concentrated foods to fatten the stock. In a few years his 

 farm became too rich to raise grain, and he had to give away his stable 

 manure for a time. Not many farmers are troubled in this way, but the 

 hint, how to intensify your manure by feeding coarse grains and bran, is 

 worth remembering. 



(2.) The value of stable manure depends upon the way it is kept. 

 Exposure to rain greatly lowers its value, especially when the drip of the 

 eaves washes the dung heap. 



Some experiments on this subject have been carried on at the college 

 this year. Three boxes, lined with tin, and with tubes to carry any wash- 

 water from rain into jugs, for analysis, were filled with 400 pounds of 

 stable manure, of the same quality, on June 29. The boxes were three by 

 four feet, eighteen inches deep. After filling and weighing, one was 

 placed where the drip from the eaves of a twenty by thirty foot barn would 

 fall upon the contents of the box; the second box was placed in the open 

 yard, where it would receive the natural rainfall, and the third box was 

 placed under shelter. The drainage from the two exposed boxes was 

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