PREPARATION AND USE OF ARTIFICIAL MANURES 

 By Karol J. Kucinski.i Research Assistant in Agronomy 



Introduction 



The Soil's Need for Manure 



In the economy of nature, the most productive soils are those rich in organic 

 matter or humus. Land which has been farmed for many years is apt to be 

 seriously deficient in organic matter. 



The incorporation of organic matter into the soil is beneficial in several ways. 

 It improves sandy soils by acting as a binder and increases their water-holding 

 capacity; loosens and lightens heavy loams and makes them easier to work; serves 

 as an important source of plant food; improves biological conditions of the soil; 

 checks leaching of plant food and erosion of soil; and helps in many other less 

 tangible ways. Manure has long been used as a source of organic matter for 

 soil improvement. 



In England, experiments at Rothamsted Experimental Station, covering from 

 seventy to eighty years, showed that when commercial fertilizers replaced organic 

 manures soil deterioration was eventually observed. Organic manures, on the 

 other hand, maintained production at a higher and more uniform level over 

 this long period, and practically no soil depletion was evident. 



These facts are of prime importance in gardening and in special intensive crop- 

 ping systems in which definite rotations with green manures cannot be, or are not, 

 employed. Unfortunately, natural manure has one drawback — there has never 

 been enough of it. This scarcity has perhaps been one of the reasons for the use 

 of non-organic chemical fertilizers. 



The rapid replacement of horses by steam- and gas-driven machines on farms 

 and in cities during the last twenty-five years has made the problem of obtaining 

 natural manure more difficult. When it is realized that each year of farming 

 tends to decrease the organic matter already in the soil; that comparatively 

 fewer animals, especially horses, are kept on the farm to supply organic material 

 by way of manure; and that more intensive cultivation is required to supply the 

 needs of an ever-increasing population, the seriousness of the organic-matter 

 problem is easily seen. 



The Possibilities of Artificial Manures 



It was to meet these conditions that work was started on the production of 

 artificial manures. England was one of the first countries to feel the scarcity of 

 barnyard manure, and it was at Rothamsted in 1919 that the process of preparing 

 artificial manure chemically was first developed. 



The biological principle underlying the preparation of artificial manure is 

 quite simple. The process of natural decay of organic material rich in carbona- 

 ceous compounds such as cellulose, lignin, starches, and sugars can be greatly 

 speeded up by the addition of readily available nitrogen and some phosphorus 

 compounds. In other words, the microorganisms which are the true agents of 

 decay need a balanced food ration in order to continue their activities and in- 

 crease in numbers. In any plant material the ratios of carbon to nitrogen and 

 carbon to phosphorus are very wide. The addition of available nitrogen and 



^Acknowledgment is made to A. B. Beaumont and W, S. Eisenmenger, who helped in outlining 

 the project and assisted in the work by their interest and many helptul suggestions. 



