Research On U.S.Hog Manure Management(1910-2010)

In the past 100 years,great changes have taken place in the concept,system and method of U.S.hog manure management.Conceptually,from treating hog manure as waste to treating it as an asset,the Americans have experienced a change in understanding of the relationship between human and nature.In terms of systems,from land application to comprehensive nutrient management,they have undergone the system transformation from crop-livestock integration to separation of crop and livestock production,and then to comprehensive nutrient management both in crop and livestock production.In terms of manure management methods,from management in small-scale pig herding and husbandry to the large-scale manure lagoon,and then to the development of environmentally superior technologies,they have gone through different historical stages of parallel,conflicting and coordination between economy and environment.According to the different practices of hog feeding operations,the U.S.hog manure management stages can be divided into four periods:the period of small-scale family farm operations from 1910 to 1958;the starting period of concentrated hog feeding operations from 1959 to 1971;the period of rapid development of concentrated hog feeding operations from 1972 to 1998;and the period of vertically integrated hog feeding operations from 1999 to 2010.At the beginning of the 20th century,under the influence of natural resource and wilderness conservation movement,the Americans began to change their attitude of nature from crazy destruction and waste of natural resources guided by "conquering nature"concept to appreciation of nature and affirmation of its intrinsic value,and tried to seek a new relationship model of harmonious coexistence between man and nature based on the protection of natural resources.This concept of "living in harmony with nature" has been fully demonstrated in the early U.S corn-belt farming systems of hogging down crops.Hog raising along with crop production depended on the recycling of natural resources.Closed nutrient circulation was formed in the chains of crops-land-hog manure,which could effectively prevent nutrient loss and environmental pollution.However,the war broke the atmosphere of harmonious coexistence between human beings and also changed the harmonious relationship between human beings and nature.During and after the war,some social elites began to restate the anthropocentrism and the supremacy of economic interests,with which the methods of hog raising and the manure management have undergone tremendous changes.After World War ?,the U.S.military industry began to shift to civilian use by large.New division of labor emerged in the agricultural arena,and agricultural production entered a stage of mechanization and chemistry in an all-round way.Some chemical enterprises that used Haber Bosch's large-scale industrial nitrogen synthesis method to produce explosives during the war had turned to produce chemical fertilizers.At the same time,pesticides and herbicides which proved by experiments during World War II to be effective to promote agricultural production also began to be produced and used on a large scale.The extensive use of chemical fertilizers broke the traditional nutrient circulation chains of returning animal manure to crop field between the animal feeding operations and the crop production sites.Hog manure was completely regarded as a waste.The pollution problems caused by the disposal of hog manure were usually solved by farmers with property protection rights according to the "nuisance law",with little government intervention and almost no supervision at all.With the expansion scale of the hog CAFOs,new methods of hog manure removal began to emerge.In 1951,Norwegian invented and used the leaky floor technology for the first time to replace artificial dung removal.In the late 1950s and early 1960s,this labor-saving dung removal method was introduced to the United States and widely used in hog feeding operations in the United States.The emergence of the leaky floor technology was a revolutionary technological innovation for the hog manure management.It not only greatly reduced labor costs and improved production efficiency,but also provided conditions for the development of large-scale hog CAFOs.From 1960 to 1969,the emergence of large-scale manure removal techniques promoted the rapid development of facility construction for hog CAFOs.The management of manure storage along with the change of manure removal method had become a new problem.With the expansion of the hog house construction,the manure storage pond had become an indispensable part of the hog house.A lagoon of manure storage replacing the traditional manure storage pit had been developed and applied ever since.With the development of hog CAFOs,the problem of pollution in American farming began to emerge.Some people with foresight in American society had begun to re-examine their previous conceptual values.From a biological point of view,Rachel Carson's " Silent Spring" used the theory of natural selection to complain the harmful consequences of the excessive use of chemical products in agriculture and the artificial creation of " super insects" and "super bacteria".She criticized the arrogant view of "anthropocentrism" of competing with all creatures and even destroying the ecological system of meeting the needs of their own interests,which caused the modern environmental protection movement.The environmental protection movement has awakened the environmental protection consciousness of the ordinary people.They begin to advocate the idea of harmonious coexistence with all creatures rather than obtaining short-sighted benefits through self-interest behaviors such as eliminating species that seems not beneficial to human beings.Some economists begin to explore new ways of economic systems.American economists Coase and Boulding put forward a new concept of environmental protection system from the perspective of economics.Coase uses the term of "social cost" to consider the subjective and objective factors of the victim and the offender.He uses the analysis method of minimizing the total social cost to determine the proportion of responsibility in environmental pollution,hoping to make the valuable natural resources flow to those who can use these resources most effectively through the most careful system design.In the early 1970s,a large amount of sewage discharged from factories,urban residents and livestock and poultry farms caused serious pollution to rivers and lakes in the United States every year.Since most of the sewage at that time came from the sewage discharged from factories and urban residents,the U.S.government treated the manure from livestock and poultry operations in the same way as the sewage from factories and urban residents according to the regulating policy against the point source pollution.In the 1980s,although the point source of wastewater in the United States was effectively controlled,the quality of the water in the whole did not significantly improve.Non-point source pollution replaced point source pollution and became the main source of water pollution in the United States.From 1982 to 1997,only about 25%of feed nutrients in hog CAFOs in the United States were converted into meat products,and about 75%of feed nutrients were found in animal manure.After the manure is applied to the limited farmland inside the farm,about 51%of the nitrogen and 64%of the phosphorus content exceed the required amount of the farmland and become the main source of agricultural non-point source pollution.Due to the malfunction of pollution control policies,the phenomenon of environmental injustice has begun to emerge and has become the focus of the environmental justice movement.In order to deal with the agricultural non-point source pollution caused by CAFOs,the United States Department of Agriculture and the Environmental Protection Agency jointly issued a unified national strategy for the management of livestock and poultry manure,and launched the Comprehensive Nutrient Management Plan for Livestock and Poultry Manure(CNMP)in 1999,which requires CAFOs to take manure as the management object by returning manure nutrient to the crop field,so as to reduce agricultural non-point source pollution through runoff and ammonia volatilization.The implementation of the comprehensive nutrient management plan extends the management of manure nutrients from animal feeding operation to crop produciton,and the management of manure application nutrients in crop field is also included in the comprehensive nutrient management plan.Under the supervision of the U.S Department of Agriculture,the chemical fertilizer industry also took the lead in introducing a universal 4R nutrient management system with scientific pioneering significance.This nutrient management system extends the nutrient management of chemical fertilizers to the manure management,thus to adjust the measures to fit local conditions and continuously improve the nutrient management on the whole.It can motivate farmers to adopt the best fertilizer management practices suitable for local conditions and realize the sustainable development of agricultural production.At the beginning of the 21st century,the lagoon systems or open-air anaerobic systems,originally widely used in southeastern United States,were widely criticized for their environmental and health problems caused by ammonia emission,odor,pathogen transmission,and water pollution.In July 2000,under the influence of Environmental Justice Movement,Smithfield Food Company,the largest pork producer in the United States,signed a cooperation agreement with the North Carolina government and North Carolina State University,agreeing to develop and use new hog manure treatment technology to change the original manure storage system.Environmentally Superior Technology(EST)therefore came into being.Environmentally Superior Technology is a technological system designed on the environmental superior principles formed during the implementation of comprehensive nutrient management plan.It is developed by the hog raising experimental base of North Carolina State University and designated by the state government as a hog manure treatment system for replacing the open anaerobic lagoons.The principle of environmental superior or environmental protection priority mainly means that in order to realize the sustainable development of human society,environment should be considered in priority so that the environmental protection behavior takes precedence over the development and utilization of the environment.During a century changes on U.S hog manure management,natural resource endowment and economic factors,social environment and policy orientation,technological progress and financial innovation,and market factors have all played important roles.There are many experiences and lessons worthwhile for learning.As the world's largest hog raising country with the largest amount of hog manure,China needs to draw upon the experience of the United States on hog manure management from the aspects of concept,system and technology,and endeavor to explore a way of hog manure management that not only suitable for China's natural conditions but also meets the goal of coordinated development of environment and economy.