Diffuse Pollution from Agriculture in the World

Document Sample
Diffuse Pollution from Agriculture in the World Powered By Docstoc
					  Diffuse Pollution from
Agriculture in the World (II)
        Vladimir Novotny
     Northeastern University
        Boston, MA, USA
     novotny@coe.neu.edu
                  IWA Diffuse Pollution Group


                  Conference “ Agriculture and
                  Environment” in Venice 1984
                  (Giorgini and Zingales
  Historic city
Algal bloom       Workshop on Agricultural Diffuse
                  Pollution in Teolo (Veneto) 1997
                  (Bendoricchio, 1999)
                  IWA Leading Edge Conference on
                  Managing Rural Diffuse Pollution,
                  Edinburgh – April 2006
                  (Contact Brian D’Arçy, SEPA)
Lagoon of Venice Problems




          •   Drainage of wetlands
          •   Intensive agriculture industrial
                  fertilizers and pesticides
          •   Urbanization and transportation
          •   Tide barrier ?
       Problems of the Baltic Sea


Nutrients (N and P)
Eutrophication
Excessive algae growth
Oxygen depletion
Problems of the Baltic Sea
     - Algae blooms

      Blue-greens
    Oxygen depletion




                             Source:
                             Claus Hagebro
                                Professional Secretary, M.Sc.
                                Helsinki Commission
   Other areas of large scale
           problems
Chesapeake Bay
• Susquehanna River
Gulf of Mexico
• Mississippi River
Black Sea
• Danube River
North Sea
• Elbe
100
 50
 20
 10
  5                                               Remaining
                                                  land use is
  2                                               mostly
  1                                               forest
 0.5                     Background level
 0.2
 0.1
0.05
0.02
0.01
       0                   50               100
           AGRICULTURAL LAND %


           Willamette River Basin, OR        Source USGS
            Problems
Eutrophication
• Dissolved oxygen, turbidity
• Algal toxins, taste and odor
• Increased cost of treatment
• Impairment of swimming (aesthetic,
  rash, gastrointestinal diseases)
Disappearance of sea grasses
Loss of diversity
Fish, shell fish and marine mammals
kills, aquatic life impairment
 Important Periods of Change of
           Agriculture
800                  1850             1950        1990

                                       Industrial fertilizers
Feudal Farming
                                       and pesticides
                     Subsistence
                     Farming

                                       Green Revolution
   Land conversion


                                                  Organic
                                                  Farming
                               1940
                                   Soil conservation BMPs
                                Root Causes of Diffuse Pollution

                                                                                                                   Population
                                                                                                                   Growth and
                               12                                               High
                                                                                estimate

                               10                                                                                  Increased
World Population in billions




                                                                                                                   Standard of
                                                                              on
                                8
                                                                       opu
                                                                          lati
                                                                                                     Low
                                                                                                     estimate      Living

                                                                                                es
                                                                                            t ri
                                                                  al P




                                                                                          un
                                6                                                                                  Need for food can
                                                                                       Co
                                                                Tot




                                                                                                                   be satisfied by
                                                                                     ing
                                                                                  lop
                                                                              ev e



                                4
                                                                                                                   • Converting more
                                                                            nD
                                                                          ni




                                                                                                                   land to agriculture
                                                                           io
                                                                       lat




                                2
                                                                    pu




                                                                                                                   • Intensification of
                                                                  Po




                                                                    Developed Countries
                                0                                                                                  agriculture
                                    1750   1800   1850   1900   1950            2000         2050    2100   2150
        Green Revolution
           (Intensive Agriculture)

              N.E. Borland




New crop cultivation methods
Developing new cop varieties
Irrigation
Dramatically increased chemical
fertilizer and pesticide applications
Mechanization
       Green revolution
Has dramatically increased crop yields
• More land would have to be converted to
  agriculture without green revolution
• It brought increased standard of living
Made traditional family farms economically
unsustainable
Diffuse pollution dramatically got worse
Farm subsidies encourage large intensive
operations
Worldwide increases in fertilizer use
                                  7

                                                                                       1990

                                  6
                                                                                                          1990

                                                                                      UK
                                  5                     1990
                                                                                                 Japan
      Cereal yields (tonnes/ha)




                                                                        1990
                                                                                  Asian yield requirement 2030
                                                         USA
                                                                               1968
                                  4

                                                                                 Asian yield requirement 2010
                                                                1961
                                  3                         China
                                          1961     1990
                                                           1990
                                  Mexico
                                                         1990       Asian yield requirement 1990
                                  2
                                                 Asia
                                                         Brazil
                                            1970
                                  1
                                                        Asian yield requirement
                                                        1960


                                  0
                                      0            100            200          300         400      500      600
                                                                                                                   Source : Ongley
                                                               Fertilizers (kg/ha)
Pollution from animal operations
Change of animal operations from small
scale family animal husbandry and pasture
to concentrated feedlots made possible by
green revolution with hundreds (cattle) or
thousands (pigs, chickens, turkeys)
animals in a small space
Consequences:
• Large increase of diffuse pollution on top of
  the nutrient losses from fields
• Poor disposal into soils
• Soil overloading, disposal on frozen soils
Pollution from land use changes
 Deforestation to subsistence farming
 Wetland drainage
 Irrigation of dry lands and irrigation return
 flow
 Cultivation of prairies
 Conversion of range land and pasture
 Conversion to aquiculture in tropical
 countries and elimination of mangrove
 wetlands
Borlaug estimated that if green
revolution had not occurred then
additional 1.8 billion hectares would
have been needed to satisfy the
current needs of population
This “new” agricultural land would
come from converted rain forest
(tropical humid countries) or from
marginal more erosive lands (China)
Nutrient Balance on a World Basis and for the European Community

                                       World          European Community

                             N                 P      N                P


Addition of Nutrients (106   tonnes)
         Fertilizer          70                14.4   9.3             2.0
         Waste products      58                12     7.1             1.4
         Atmosphere          89                 -     1.3               -
Total (Kg/ha)                13                 5.6   96              26.8

Extraction of Nutrients (106 tonnes)
  Crop production           60                 12     10              1.9
         Denitrification   157                  -     4.3              -
Total (Kg/ha)               13                 2.5    78              15

Net addition (Kg/ha)          0                +3.1   +18             +1.8
Accumulation in soils and aquatic
           systems
20% of applied phosphorus and 50% of applied
nitrogen to land reach receiving waters (NAWQA)
Accumulation rate of phosphorus ranges 3 to 18
kg ha-1 year-1
Highest accumulations of nutrients from
fertilizers and waste application
•   Japan
•   EC Community
•   US
Fertilizer use on suburban lawns in the US is
several times larger (per unit area) than that ob
farms
Nutrient balance and content of Vltava
River in Czech Republic (Slapy Reservoir)

    120                                                             5

    100
             Nitrogen fertilizer rate                               4

    80
                                                                    3
    60
                                                                    2
    40

                                                                    1
    20
                          Phosphorus fertilizer rate
     0                                                              0
      1959    1964    1969    1974      1979   1984   1989   1994

                                 YEAR
     IMPACT OF AGRICULTURE
Intensive agriculture
in the “Bread/Corn
basket of America”
High nutrient loads to
the river and the Gulf
of Mexico
Nitrogen is the
limiting factor for the
eutrophication            Gulf of
problems in the Gulf      Mexico
of Mexico
              Extent of Hypoxia in the Gulf




                           400 km




   Frequency of Occurrence 1985 - 1999
                                       Rabalais, et al.
Distance Paris to London    = 490 km
                                                          22
Area of hypoxic zone 1985 - 2002
                               25 000


                               20 000
      2
       Area of Hypoxia in km


                           15 000



                         10 000


                               5 000



                                   0
                                        19851986 198719881989199019911992 19931994199519961997 19981999200020012002


     Note: Hypoxia in the Gulf is defined as less than 2 mg/L of DO


                                                 Source Rabalais et al.

By interpolation, hypoxia problems started around 1960
          Overall balance of nitrogen
                                               8.0
Annual N input in Mississippi/Arkansas Basin



                                               7.0     soil mineralization - land conversion


                                               6.0   RESILIENT      VULNERABLE                     IMPAIRED
                                               5.0                                        fertilizer
                       10 tons




                                               4.0
                         6




                                                                                       legumes and pasture
                                               3.0
                                                                             all manure
                                               2.0
                                                                                               atmospheric nitrate
                                               1.0                       atmospheric ammonia
                                                                 municipal and industrial
                                                0
                                                     1950        1960       1970          1980         1990          2000
                                                                                YEAR
         Phases of hypoxia
Conversion of prairies and subsistence
farming - late 1800 -1950 steady state –
period of resilience
Introduction of commercial fertilizers after
1950 upset the steady. Hypoxia might
have started around 1960 but was not
observed until 1985 – period of
vulnerability
Hypoxia appeared after 1980 with
concurrent diminishing of shellfish
population – period of impairment
Subglobal transport of nitrogen




                      Source:
                      National Research
                      Council
 Diffuse pollution is related to or a
consequence of the use or misuse
               of land

 Agricultural Diffuse Pollution is caused
 mostly by misuse and overuse of land
        Community response
Intensive research and development of
BMPs
•   Soil conservation (since mid 1930s)
•   Integrated pest management
•   Buffer strips and field borders
•   Animal feedlot management
•   Targeting fertilizer needs of crops
•   Incorporation and restoration of wetlands
Grass root movement to organic farming
Taking polluting agricultural lands out of
production
      Three types of farming
Subsistence (mostly small family farms)
• Expanded by land conversion
• Without education and some incentives hardly
  environmentally sustainable (slash, burn, farm and
  move away)
• Subsistence farmers in developing countries often may
  not reason beyond providing food for their families
Commercial (Large industrial farms and animal
operations)
• High reliance on fertilizers and pesticides, mostly
  monocultural
• Large increase of nutrient inputs into receiving waters
          Organic Farming
  Ecologically manageable systems
  Still relatively small
  Dramatic growth in Europe and US
  Is it sustainable and/or less
  polluting?


Converting the entire agriculture sector
to organic farming is a challenge and
only a long term goal
      Sustainable Agriculture?
Shortest definition of sustainability:
A sustainable agriculture is one that, over a long
term, (1) enhances environmental quality and the
resource base on which agriculture depends, (2)
provides for basic human food and fiber needs, (3) is
economically viable, and (4) enhances the quality of
life for farmers and the society as whole


                 American Society of Agronomy


   Dream, Conflicting or Achievable?
Three Types of Farming

Parameter                        Subsistence           Commercial        Sustainable (organic)


Social identity                  Family                Corporation       Family or Community
Nature of change                 Uncontrolled          Controlled        Planned and anticipated
Government support               Education and         Subsidies for     Same as subsistence
                                  grants for BMPs      production
                                                       and set- aside
                                                        land
Relation to environment          Vulnerable            Control over       Anticipatory
Natural resources                Finite; consume;      Develop and        Finite; conserve and
                                 relocate when         and consume        preserve
                                 exhausted
Role of government               Undeveloped and        Coordination,     Regulate
                                 unstable               protect rights
                                                        and needs of
                                                        land owners
Knowledge base                   Tradition             Science and       Science and
                                                        technology       technology
Impact on diffuse pollution      Localized, could be   Significant and   Small, often none
                                 significant over       widespread
                                 long term
Cost of externalities            Medium                Large              None



From Novotny (2003) and Padgitt and Petrzelka (1994)
              Conclusions
Over the last 50 years there has been a dramatic
shif from subsistence family farming to
commercial large scale farms and feedlots with a
consequence of large losses of fertilizers into
receiving waters (diffuse pollution)
More environmentally sustainable farming is
emerging
Ecologically sustainable (minimum diffuse
pollution) farming may emerge by a conversion
of large farm operations to more sustainable
farming. This can only be achieved by
regulation and rethinking or eliminating subsidies
In memoriam
Professor
Giuseppe
Bendoricchio
1950-2003


Founder of the IWA
Diffuse Pollution Group