10 



MISCELLANEOUS PUBLICATION NO. 1065, U.S. DEPARTMENT OF AGRICULTURE 



though that which received no treatment or 

 only primary treatment could not be used in 

 the production of food crops. Such water may 

 be used for irrigating feed and fiber crops. 

 Further, effecting movement of such contaminated 

 water through soil is the best means of attaining 

 purification. 



The State agricultural experiment stations and 

 the U.S. Department of Agriculture have already 

 developed useful information on irrigation with 

 sewage effluent both in terms of crop production 

 per se, and in terms of overirrigation to provide 

 ground water recharge with reclaimed water. 



The good prospects of this research in sustaining- 

 agricultural water supplies in the future, in addi- 

 tion to providing an effective system of water 

 purification, require that this line of endeavor be 

 supported to the fullest extent feasible. 



Animal Wastes 



Domestic animals produce over 1 billion tons 

 of fecal wastes a year. Their liquid wastes come 

 to over 400 million tons. Used bedding, paunch 

 manure from abattoirs, and dead carcasses make 

 the total annual production of animal wastes close 

 to 2 billion tons. In fact, waste production by 

 domestic animals in the United States is equivalent 

 to that of a human population of 1.9 billion. 



As much as 50 percent of this waste production 

 may be produced in concentrated supply. Big 

 operations have developed rapidly in the last 20 

 years. An outfit with 10,000 head of cattle on 

 a feedlot produces 260 tons of manure a day. 

 Economic research reveals that it is cheaper for 

 the farmer to supply fertility to his fields from 

 the fertilizer bag than to meet the cost of hauling 

 manure to the field. What is to be done with this 

 manure? 



If it accumulates, it effuses offensive odors into 

 the surrounding area; it provides a spawning 

 ground for vermin; on drying, it is a source of 

 unsavory dusts; in rainstorms it produces runoff 

 high in biochemical oxygen demand ; and it may 

 be the source of certain infectious agents found 

 in streams. 



Stockmen have been subjected to lawsuits on the 

 grounds that such wastes were a public nuisance. 

 Dairy farmers have had to make expensive moves 

 to remote areas. Poultry enterprises have offended 

 and been placed under restrictive curbs. 



There is a pressing need to develop basic design 

 criteria that are amenable to some adjustment to 

 meet the widely varying constraints associated 

 with different enterprises in different parts of the 

 country. Elements of the problem include char- 

 acteristics of manures; removal of mamire from 

 livestock quarters; storage; transport; feasibility 

 of use on land; and disposal by burning, using 

 lagoons or similar facilities, or burying. Other 

 disposal problems include handling carcasses, 

 milkroom wastes, and silage effluents. 



Much effort should be allocated to identify the 

 odor-producing organisms prevalent in manures, 

 and to develop techniques to destroy such or- 

 ganisms. 



Treatments of manure that would lower its at- 

 tractiveness as a breeding ground for flies and ver- 

 min are especially needed. 



In applying manure to cropland, more accept- 

 able procedures are needed for storage and dis- 

 tribution without emission of offending odors and 

 possibility of contamination of runoff water. 



Use of lagoons for disposal has not been f un- 

 satisfactory. They tend to be underdesigned, over- 

 loaded, and misused. Anaerobic fermentation with 

 the accompanying odors sometimes takes place. 

 Some study is underway and must be continued 

 to provide artificial stirring and better oxidation 

 of water systems used for manure disposal. 



The looming urgency of disposal problems on 

 animal wastes, associated with a serious dearth of 

 needed technology on efficient and economic meth- 

 ods, adds up to an immediate need for major ex- 

 pansion of research effort to attain sound answers 

 to these problems. 



Plant Residues 



Plant residues from crops and orchards impair 

 the environment in two ways: (1) They act as 

 reservoirs of plant diseases and pests, and (2) they 

 emit smoke and hydrocarbons into the surround- 

 ing area when burned. Rice stra.w as well as that 

 of other grains is burned. Burning of residue 

 from grass seed production is used extensively as 

 a sanitation measure. Alternate methods of hand- 

 ling such residues are needed. 



If residues are left on the soil, they can aid in 

 preventing wind and water erosion. However, the 

 soil microflora may be altered in nature and ac- 

 tivity, as a result of a mulch of crop residue, and 



