112 STATE HORTICULTURAL SOCIETY. 



MANURE IN HORTICULTURE. 



BY PROF. R. C. KEDZIE, AGRICULTURAL COLLEGE. 



Twelve years ago I read a paper before this society, on "Manures in 

 Horticulture," but he is an egotist who imagines the public will remember 

 what he said a dozen years ago. You will pardon me if I repeat some of 

 the things I then said. It is not a matter of first importance to say some- 

 thing new, but rather to say what is true. 



Different classes of animals require different kinds of food: the dog will 

 thrive on meat, but starve on grass; while the ox would go hungry on the 

 best beefsteak, but grow fat on hay and corn. In like manner it was once 

 supposed that plants, with their widely varying qualities, needed corre- 

 spondingly different kinds of manure; but it is found that plants grown 

 either on farm or in garden have practically a very uniform composition 

 and require the same natural elements. 



The Agricultural Thirieen. — Only thirteen elementary substances are 

 found in crops, and this baker's dozen make up the innumerable forms of 

 plant life. These elements come from air and soil through the ministry 

 of water. Carbon makes up one half of all vegetable substances, but it 

 comes to the plant frcm the atmosphere in the form of carbonic acid, and 

 it is literally as free as air. We need give it no thought in our scheme of 

 manures. Oxygen and hydrogen are furnished to the plant in the form of 

 water, which comes from the air in its journey by the sky-route from 

 ocean to ocean, and is only stored for the time in the soil. But water is a 

 prime physical condition of plant life. If the benediction of the sky is 

 withheld, in vain the efforts of the husbandman. A rainless land is a 

 dusty desert, no matter how rich in manurial elements; and almost any land 

 can be made productive if plenty of water is furnished. Dr. Sturtevant 

 published a very striking lecture, " Water the Universal Manure." You 

 all recognize the importance of water in horticulture, and that, with 

 abundant and well-distributed rain, successful crops are sure, while the 

 dreaded drouth is death to the hopes of the fruitgrower. 



Sodium and chlorine, in form of common salt, are found in quantity 

 ■sufficient for most plants, in all the soil- waters of the state. Silica and 

 oxide of iron are found in ample supply in all our soils. Sulphate of lime 

 furnishes the plant with the required amount of sulphur, and lime and 

 magnesia are found in most soils in sufficient supply for the ash of plants. 

 This accounts for ten of the thirteen chemicals of agriculture, all abund- 

 antly supplied to the plant by the liberal hand of nature to all Michigan 

 soils, or easily supplied by two cheap and abundant manures, viz.: salt and 

 plaster. 



In this discussion I confine myself to the direct needs of the plant for 

 growth, and do not consider the indirect influence of some of these sub- 

 stances by inducing changes in the inert materials of the soil, such as the 

 effects produced by lime, plaster, salt, and the vegetable matter or humus 

 of soils. 



The Tripod of Agriculture. — The preceding discussion has shown that 

 ten of the thirteen chemicals of agriculture are either supplied in exhaust- 



