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MISCELLANEOUS PUBLICATION NO. 10 65, U.S. DEPARTMENT OF AGRICULTURE 



as a fertilizer. An excellent summary of this infor- 

 mation is found in Ohio Agricultural Experiment 

 Bulletin 605 (96). The conclusion was reached that 

 the crop production potential of manure is largely 

 derived from its nitrogen, phosphorus, and potas- 

 sium contents. The nitrogen in the urine was evalu- 

 ated as being equally as available as that in min- 

 eral fertilizers, but the availability of nitrogen in 

 solids of barnyard manure was considered to be 

 only 25 to 50 percent of that in chemical fertilizers 

 depending on the kind and nature of storage. 

 Availability of phosphorus and potassium in 

 manure was evaluated as about the same as that in 

 mineral fertilizers. 



In further review of available evidence, the U.S. 

 Department of Agriculture (32) finds that on soils 

 of good tilth, manure has value only for its plant 

 nutrient content : but on soils in poor tilth, manure 

 has a value above and beyond its nutrient content. 



Marked improvements in the techniques for 

 making fertilizer from atmospheric nitrogen were 

 made in the period before "World War II. During 

 the war, the Federal Government built numerous 

 plants for the manufacture of fixed nitrogen for 

 munitions. At the war's end, these plants became 

 available for making farm fertilizers at a relative- 

 ly low price. The price has remained compara- 

 tively low ever since, whereas other farm costs 

 have advanced appreciably. This has led to the 

 situation in which nitrogen from chemical ferti- 

 lizers is cheaper than that from manure, even if 

 only handling charges of the latter are taken into 

 account. This simple economic fact deters use of 

 manure for land improvement and contributes to 

 the problem of disposing of wastes that accumu- 

 late from large operations. 



The Illinois Agricultural Experiment Station 

 (129) has studied the economic value of manure 

 handling from hog lots. The report on this study 

 states : 



Spreading solid manure on cropland rather than 

 dumping it in a disposal area is still a profitable 

 practice because there is little difference between 

 spreading and disposal costs. 



However, liquid handling systems for manure 

 are of increasing interest for those raising hogs in 

 confinement systems. The Illinois report also 

 states : 



The most profitable practice for the average 



farmer who raises hogs in confinement is to dis- 



pose of the liquid manures in a lagoon and use 

 commercial fertilizer on his fields. 



A report (86) of a study at Purdue University 

 on the economics of handling manure is also of 

 interest. Three statements are pertinent: 



In general, the scale and efficiency of the opera- 

 tion and prevention of dilution of the manure 

 determine if the manure can be spread in the 

 fields at the cost equal to or less than the value of 

 the nutrients used by the crops. 



Aerobic and anaerobic treatment of manure in 

 special low-cost facilities designed for use on the 

 farm seem to be practical solutions. 



No profitable method of industrial utilization of 

 livestock manure can be forseen. 



The high moisture content of manure is a major 

 factor in its bulk handling cost. A number of State 

 agricultural experiment stations — -for example, 

 Michigan, Nebraska, and New York — have re- 

 search underway to develop an economical proce- 

 dure for dewatering manure. 



Efficient systems of handling manure analogous 

 to sewage-handling systems are being developed at 

 a number of State stations— for example, Massa- 

 chusetts, Minnesota, Ohio, and South Dakota. The 

 Pennsylvania station has carried on outstanding 

 research for using sewage effluent on the land. 

 Technical Bulletin 675 (58) reports on use of sew- 

 age effluent for irrigation of cotton and pasture. 

 The New Jersey station has developed a plow- 

 furrow-cover technique that tends to conserve the 

 value of manure, while minimizing its adverse 

 effects in the environment. 



The use of lagoons for disposal of manures is 

 under study by the U.S. Department of Agricul- 

 ture and a number of State experiment stations 

 (33, 3Ji). Many are poorly designed, overloaded, 

 and misused. The South Dakota station has re- 

 ported adversely on lagoons. The U.S. Department 

 of Agriculture is also studying the possibilities of 

 growing grasses hydroponically in lagoon and 

 other effluents to remove the plant nutrients 

 (N, P, & K) and trace elements. This procedure 

 would keep these nutrients from reaching and 

 supporting aquatic plant growths in receiving 

 streams and also help provide additional livestock 

 feed. 



Several experiment stations in the Midwest are 

 making improvements on the Pasveer system — a 

 system developed in Holland to handle sewage 

 from small cities by artificial stirring to improve 



