Energy and Agricultural Carbon Utilization Symposium

Transcription

1 Energy and Agricultural Carbon Utilization Symposium June, 2004 University of Georgia Athens, GA Impacts of intensive agriculture on soil carbon, crop productivity and climate change. by D.C. Reicosky Agricultural Research Service "SOILS LAB" * MORRIS USDA-ARS-MWA North Central Soil Conservation Research Laboratory Morris, MN USA

2 Pyrolysis of agricultural biomass is a part of carbon linkage and cycling in agricultural ecosystems. Charcoal Soil conditioners Agricultural crop residues Biological nutrient cycling Integrated energy byproducts Terra Preta soils Char Wood chips and byproducts Forest wood residues Microenvironment for microbes Energy source for microbes and fungi Ammonium carbonation for fertilizer

3 We have only one Earth!

4 Carbon is the key linkage of the 3 E s Environment Agricultural Biomass Carbon Economy Energy

5 3 Pillars of Conservation Agriculture! Conservation Agriculture minimum soil tillage crop rotations/ cover crops Continuous residue cover Soil Organic Carbon

6 True Conservation Agriculture is carbon management. Conservation agriculture provides beneficial ecosystem services: 1. Food and fiber and biofuels 2. Less erosion, less pollution, clean water, fresh air, healthy soil, natural fertility, higher production, carbon credits, beautiful landscape, sustainability etc., etc. Soil carbon is a priceless key to the planet s health and our environmental quality.

7 Conservation Agriculture is carbon management. Conservation Agriculture is good for a lot of reasons. Climate change is just one of those reasons. Global Perspective

8 Greenhouse Effect and Global Climate Change The role of agricultural tillage and soil carbon

9 LIST OF GASES THAT CAUSE GREENHOUSE EFFECT GREEN HOUSE GAS Carbon Dioxide CO 2 Methane CH 4 Chloroflourocarbons CFC Nitrous Oxide N 2 O Other (O 3,H 2 O,NO x,co,etc.) PERCENT OF GREENHOUSE EFFECT Source: Bouwman, 1990; USEPA Report, 1990

10 Soil Organic Carbon (%) Midwest USA Long Term Effects of Crop Rotations Estimated to 4 % in 1888 Wagner (1989) Sanborn Field: Missouri Wheat, 6 Tons Manure/year Corn, 6 Tons Manure/year Continuous Wheat Continuous Corn Morrow Plots: Illinois Corn-Oats-Hay Rotation Corn-Oats ( , Corn-Soybeans (1954-Present) Continuous Corn Year

11 Possible explanations for soil carbon decline. 1. Intensive tillage - moldboard plow and disk harrow. 2. Changing from perennial species (60 to 90 % of biomass below ground) to annual agronomic species (15 to 20 % of biomass below ground). 3. Increased organic matter mineralization as a result of increased use of inorganic nitrogen fertilizers. (Lit. cit. Green et al., 1995, SSSAJ 59: )

12 No. 1 Environmental Enemy in Production Agriculture Intensive Tillage

13 Carbon Cycle in Agriculture CO 2 Photo n Respiratio synthesis Soil Organic Matter Decomposition Crop Biomass

14 Soil organic matter is a mixture of residual plant material in various stages of decomposition and microbial biomass and all their bi-products. The key component is: C

15 Soil carbon is linked to all measures of soil quality. Biological Soil Carbon Physical Chemical

16 Conservation Agriculture Manage soil carbon! Delay Decay

17 CO 2 Carbon Cycle - a fantastic voyage Green plants Crop Residue/Stubble Decomposition Cycle as a temporal continuum with carbon changing form and function as CO 2 is released through microbial respiration. CO 2 CO 2 CO 2 CO 2 CO 2 Basic elements Stubble residue Active pools ---- Organic matter --- humus Humic fulvic acids Passive pools ---- Recalcitrant pools

18 Agriculture has dug a carbon hole with intensive tillage. Agriculture can now refill the carbon hole with less intensive tillage. Tillage-induced Carbon Dioxide Loss CO 2 CO 2

19 M = Mobile MR. GEM R. = Research G = Gas E = Exchange M = Machine Invisible effects of invisible forces!

20 Invisible effects of invisible forces! Intensive tillage enhances biological oxidation and decreases soil carbon irrespective of residue management. CO 2 $ $ $ $ Tillage very effectively facilitates biochemical degradation of organic matter.

21 Invisible forces of aerodynamics lifts carbon dioxide out of tilled soil. 25 cm BEFORE AFTER MOLDBOARD PLOW Tillage loosens the soil (i.e. changes soil air permeability) and enables rapid soil gas exchange. Soil carbon dioxide is sucked and swirled into turbulent eddies on into the atmosphere. Oxygen enters the large voids to enhance microbial activity. Tillage unlocks the potential microbial activity by creating more reactive surface area for gas exchange on soil aggregates that are exposed to a higher ambient oxygen concentration (21%). Tillage also breaks the aggregates to expose "fresh" surfaces for enhanced gas exchange and perhaps more carbon loss from the interior that may have a higher carbon dioxide concentration.

22 Carbon is a keystone in nutrient cycling! Zn Cl Mg K N C P Ca Soil carbon is the Keystone for all soil physical, chemical and biological processes and properties. S Mn Bo Management platform fertility, variety, irrigation, species, cover crop, manure, rotations, tillage, soil type, erosion, timing,

23 Biological nutrient cycling requires carbon! N P K S Zn Ca C Mg Bo Cl etc. Mn

24 Nutrient Balance and Carbon Sequestration. N P Net carbon sequestration requires other nutrients. Ca S C K Zn 7 10 units of C per unit of N units of C per unit of P Bo Mg units of C per unit of S Cl etc. Mn Balanced fertilization is needed for both crop uptake and carbon sequestration! Rattan Lal, 27 Jan., 2000

25 Environmental Quality Triangle Air Q Water Soil Soil Quality is the foundation of Environmental Quality.

26 Soil Carbon Sequestration Environmental benefits are spokes that emanate from the Carbon hub. - increased water holding capacity and use efficiency - increased cation exchange capacity - reduced soil erosion - improved water quality - improved infiltration, less runoff - decreased soil compaction C - improved soil tilth and structure - reduced air pollution Carbon - reduced fertilizer inputs - increased soil buffer capacity - increased biological activity - increased nutrient cycling and storage - increased diversity of microflora - increased adsorption of pesticides - gives soil aesthetic appeal - increased capacity to handle manure and other wastes -more wildlife central hub of environmental quality.

27 Atmospheric Carbon as CO 2 Time Frame of Carbon Cycles Fossil carbon cycle. Cycle time is millions of years for fossil carbon. Biological carbon cycle. Cycle time is 1-10 years for biological carbon. Nonrenewable Renewable The major strength of biofuels is the potential to reduce net carbon dioxide emissions to the atmosphere.

28 Fossil carbon cycle. Nonrenewable Biological carbon cycle. Renewable Atmospheric Carbon as CO 2 CO 2 CO 2 CO 2 Energy from fossil fuels Energy from bio-fuels C Plant biomass and roots left on or in the soil contribute to Soil Carbon or Soil Organic Matter and all associated environmental and production benefits.

29 Conservation Agriculture (Direct Seeding or No-Till farming) CO 2 CO 2 combustion O 2 Agriculture s role in the carbon cycle. CO 2 O 2 O 2 CO 2 CO 2 respiration O 2 photosynthesis Credit : 1998 Jim Kinsella,

30 Renewable energy resources wind solar hydroelectric Constantly replenished with environmental benefits obvious because no CO 2 emitted in the generation and no CO 2 taken up, not part of the fossil or biologic carbon cycle. Constantly replenished with environmental benefits that CO 2 emitted in combustion is recycled into biomass through photosynthesis as part of the biological carbon cycle, thus no net increase in CO 2 emissions. biofuels biological feedstocks cellulosic biomass, ethanol feed grains, ethanol, methanol crop and vegetable oils, sunflower, soybean starch and sugar waste streams wood and logging residues, hybrid poplar energy crops-annual and perennial,switch grass municipal and industrial waste, sewage sludge methane from manure production turkey manure

31 The major strength of renewable fuels is the potential to reduce net carbon dioxide emissions to the atmosphere. Atmospheric carbon management is a two-way street: carbon in and carbon out of the system. Renewable fuels or biofuels combustion emits carbon dioxide like fossil fuels, however, renewable fuels close the carbon cycle by reusing carbon dioxide through photosynthesis to form new plant biomass. Fossil fuels combustion emits carbon dioxide from a very old carbon sources that do not close the carbon cycle by reusing carbon dioxide in a reasonable time to form new biomass.

32 Benefits of the Biobased Economy Economic Reduce cost, better control of product properties New product & market opportunities Improved balance of trade & energy independence Environmental Pollution prevention, reduced emissions of GHG and toxics Green fuels, chemicals & materials Reusable & recyclable products Social Rural economic diversification & growth Developing countries can access the biobased economy Improvements in human/environmental health & quality of life

33 Switch grass Switchgrass keeps the carbon out of the air and in the soil! Environmental benefits of switch grass as a bio-fuel. -- decreased soil erosion -- decreased water pollution and sedimentation -- decreased greenhouse gas emissions -- increased wildlife habitat -- carbon sequestration (tradable carbon credits) -- low chemical inputs (fertilizer, herbicides) -- perennial grass Tolbert, V Environmental effects of biomass crop production. What do we know? What do we need to know? Guest Editor. Biomass and Bioenergy 14(4):

34 ECOSS Fertilizer Schematic Enriched Carbon Organic Slow release Sequestering Fertilizer Carbon capture through photosynthesis Hydrogen for fuel cells Controlled slow release N fertilizer Increased agricultural productivity Agricultural and Forestry Crop Biomass Carbon management through pyrolysis N 2 Improved Environmental Quality N fertilizer without use of fossil fuel Semi-permanent soil C sequestration via char bi-product Decreased CO 2 and N 2 O emissions, less denitrification

35 Conservation Agriculture is Carbon Management! Economic prosperity Environmental protection Social Responsibility Direct seeding is a new technology that provides food and fiber and helps protect the environment.

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37 Carbon in the soil is like money in the bank! $ principle < > soil organic matter $ interest < > crop stover (residue) $ withdrawal < > intensive tillage $ re-invest interest < > conservation tillage and surface residue Now with possible carbon credits, it s real money$$$ Piggy Bank Soil Bank

38 Estimates of global carbon sequestration markets The U.S. Agriculture Department estimates that the U.S. carbon sequestration market could swell to $5 billion per year by The World Bank has estimated that greenhouse gas trading will be a $10 billion market by The investment bank Rothschild Bank Australia said it was estimated that the global carbon trading market could be worth up to $150 billion by Deutsche Bank has pegged the global emissions market at about $100 billion by 2010, about half the size of the U.S. wholesale electricity market.

39 Chicago Climate Exchange sm 25 Leaders from Energy, Industrial, Farm and Forest Sectors to Design New Chicago Climate Exchange sm Carbon Trading Markets As proposed, the Exchange could: 1. demonstrate that greenhouse gas trading can achieve real reductions in emissions across different business sectors; 2. help discover the price of reducing greenhouse gases; 3. develop the standard frameworks for monitoring emissions, determining offsets and conducting trades needed for a successful market. Web site: Web site: IGF Insurance Company is the fifth-largest crop insurance company in the industry that specializes in agribusiness risk management. Web site: Web site: World Bank's Prototype Carbon Fund Web site: Suppliers of Carbon Emission Reduction Credits TM Web site:

40 Global Environmental Quality depends on soil quality. Tillage intensity Carbon inputs C a r b o n C a r b o n Sustainable agriculture Climate Vegetation Topography Parent material Age Soil organic carbon

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43 3 Pillars of Conservation Agriculture! Conservation Agriculture minimum soil tillage crop rotations/ cover crops Continuous residue cover Soil Organic Carbon

44 Many environmental benefits point to carbon!

45 Soil Erosion Redistribution of soil within the landscape by: wind water tillage Rolling terrain with Eroded Landscape A horizon B (AC) horizon C horizon Original Surface A Accumulated Soil } B C Credit: Michelle Erb and David Lobb

46 CO 2 CO 2 Incorporating crop residues with intensive tillage maximizes residue-soil contact and is the fastest way to convert soil organic matter to a puff of carbon dioxide.

47 Carbon in the soil is the cradle of environmental quality! Global Environmental Quality

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51 5 hours after tillage 24 hours after tillage Cum. CO 2 Loss (g CO 2 m -2 ) MP SS MK YK RM NT MP SS MK YK RM NT Tillage Type

52 CER (g CO 2 m -2 ) Strip Tillage #1 3 June 1997 Swan Lake Cumulative Carbon Dioxide Loss after 24 hours RM NT MK L128 SS y = x R 2 = Increasing carbon loss MP Cross Sectional Area Loosened Soil (cm 2 )

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54 Nature s Interdependent Tri-Cycles: Water, Carbon, Nitrogen, Tillage disrupts the natural cycles! H 2 O C N Tillage Layer Properties and Processes Physical Chemical Biological

55 Cumulative Et Values Strip Tillage #2 7/16/97 MP = 5.23 times more evap. than NT in 24 h. Evaporation (mm) Hours 24 Hours Plow Subsoil Mole Knife Residue Management Yetter Knife Not Tilled Tillage Method