Carbon Sequestration and Land Degradation

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Carbon Sequestration and Land Degradation Lecture # 03 Environment and crop production (AGR-411)

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Presentation Outline Carbon sequestration concepts and rationale Relevant management approaches to avoid land degradation and foster carbon sequestration Summary of research quantifying soil carbon sequestration

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Global Concern is in the Air The difference of radiant energy received by the Earth and energy radiated back to space

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Greenhouse effect The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions.

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Melting of Alaska’s Muir Glacier between 1948 and 2004

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Why are Greenhouse Gases Important? Global ecological concern for the anthropogenic source of increasing concentration in the atmosphere since 1750 (Intergovernmental Panel on Climate Change, 2001): CO2 – 31% increase CH4 – 151% increase N2O – 17% increase Cause radiative forcing of the atmosphere, which could alter global temperature and ecosystem functioning Can be manipulated by human activities

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Projected Effects of Global Warming and the Resulting Changes in Global Climate

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Managing Carbon Emission Rising concentration of greenhouse gases has been largely attributed to expanding use of fossil fuels as an energy source, resulting in emission of CO2 to the atmosphere Reducing net greenhouse gas emission is possible: Reduce fossil fuel combustion by becoming more energy efficient Rely more on low-carbon energy sources Solar energy capture Wind power generation Biomass fuels (fuel that contains energy from geologically recent carbon fixation. These fuels are produced from living organisms.) Carbon sequestration

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Carbon Sequestration Carbon sequestration is the process of capture and long-term storage of atmospheric carbon dioxide and may refer specifically to: "The process of removing carbon from the atmosphere and depositing it in a reservoir."

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Carbon Sequestration Long-term storage of carbon in: Terrestrial biosphere Underground in geologic formations Oceans so that the buildup of CO2 will reduce or slow

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Terrestrial Carbon Sequestration Increasing the net fixation of atmospheric CO2 by terrestrial vegetation with emphasis on enhancing physiology and rate of photosynthesis of vascular plants Retaining carbon in plant materials and enhancing the transformation of carbon to soil organic matter Reducing the emission of CO2 from soils caused by heterotrophic oxidation of soil organic carbon Increasing the capacity of deserts and degraded lands to sequester carbon

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Terrestrial Carbon Sequestration

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Focus on maximizing carbon input Plant selection Species, cultivar, variety Growth habit (perennial / annual) Rotation sequence Biomass energy crops Tillage Type Frequency Fertilization Rate, timing, placement Organic amendments Management Approaches to Sequester Carbon from Atmosphere to Biosphere Integrated management Pest control Crop / livestock systems

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Focus on minimizing carbon loss from soil Reducing soil disturbance Less intensive tillage Controlling erosion Utilizing available soil water Promotes optimum plant growth Reduces soil microbial activity Maintaining surface residue cover Increased plant water use and production More fungal dominance in soil Management Approaches to Sequester Soil Carbon from Atmosphere to Biosphere

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Tree plantings Conservation-tillage cropping Animal manure application Green-manure cropping systems Improved grassland management Cropland-grazingland rotations Optimal fertilization Management Practices to Sequester Carbon and Counter Land Degradation

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Tree plantings have the advantage of accumulating carbon in perennial biomass of above- and below-ground growth, as well as in soil organic matter. Tree Plantings Issues of importance are: Climate Selecting adapted species Soil condition Plant density Intended use Type of intercropping

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Tree Plantings

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Minimal disturbance of the soil surface is critical in avoiding soil organic matter loss from erosion and microbial decomposition. Conservation-Tillage Cropping

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In the USA and Canada, no-tillage cropping can sequester an average of 0.33 Mg C/ha/yr. Conservation-Tillage Cropping Franzluebbers and Follett (2005) Soil Tillage Res. 83:1-8

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No tillage needs high-residue producing cropping system to be effective. Conservation-Tillage Cropping Soil Organic Carbon Sequestration in the Southeastern USA ---------------------------------------------------- 0.28 + 0.44 Mg C/ha/yr (without cover cropping) 0.53 + 0.45 Mg C/ha/yr (with cover cropping) Franzluebbers (2005) Soil Tillage Res. 83:120-147. Photos of 2 no-tillage systems in Virginia USA

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From the 12th year of an irrigated wheat-maize rotation in the volcanic highlands of central Mexico, rate of water infiltration, crop yield, and soil organic C reflected differences in surface soil condition due to residue management: Conservation-Tillage Cropping Govaerts et al. (2006) Soil Tillage Res. (in press) Infiltration Yield (Mg ha-1) 1996-2002 Tillage Residues (cm h-1) Maize Wheat ------------------------------------------------------------------------------------------------ Zero Without Zero With ------------------------------------------------------------------------------------------------ 18 90 3.4 4.8 3.9 5.4 Retaining residues for 12 years significantly increased soil organic C, but absolute treatment values were not reported.

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Animal Manure Application Since animal manure contains 40-60% carbon, its application to land should promote soil organic C sequestration. Soil Organic C (Mg ha-1) Effect of manure application Without With ---------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------- 2-yr studies (n=6) 19.8 + 8.9 19.6 + 8.4 11 + 8-yr studies (n=8) 30.6 + 11.4 36.8 + 10.6 SOC sequestration for all (Mg ha-1 yr-1) 0.26 + 2.15 SOC sequestration for >2-yr studies 0.72 + 0.67 Conversion of C in poultry litter to soil organic C was 17 + 15%. Note: Manure application transfers C from one land to another. Franzluebbers (2005) Soil Tillage Res. 83:120-147.

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Animal Manure Application Long-term studies on farmyard manure (FYM) application to soil clearly show its benefit to soil fertility, yield enhancement, and soil C storage: Kapkiyai et al. (1999) Soil Biol. Biochem. 31:1773-1782 18-yr field experiment in Kenya (23 °C, 970 mm) 0.17 + 0.07 Mg C ha-1 yr-1 with 10 Mg ha-1 yr-1 FYM compared to without FYM 9 + 3% of added C retained in soil Crop yield with FYM (5.3 Mg ha-1) > without FYM (3.3 Mg ha-1) Agbenin and Goladi (1997) Agric. Ecosyst. Environ. 63:17-24 45-yr field experiment in Nigeria (28 °C, 1070 mm) 0.21+ 0.01 Mg C ha-1 yr-1 with 5 Mg ha-1 yr-1 FYM compared to without FYM Total soil phosphorus increased with FYM (21 + 12 kg ha-1 yr-1)

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Animal Manure Application Gupta et al. (1992) Arid Soil Res. Rehabil. 6:243-251 20-yr study in India (26 °C, 440 mm) Pearl millet–wheat

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Animal Manure Application Soil carbon retention rate from manure application is affected by climatic condition: Temperate or frigid regions (23 + 15%) Thermic regions (7 + 5%) Moist regions (8 + 4%) Dry regions (11 + 14%) Percentage of carbon applied as manure retained in soil (review of literature in 2001)

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On an abandoned brick-making site in southeastern China (16.5 °C, 1600 mm) [Zhang and Fang (2006) Soil Tillage Res. (in press)], Planting of ryegrass (Lolium perenne) under China fir (Cunninghamia lanceolata) for 7 years resulted in soil organic C sequestration of 0.36 + 0.40 Mg C ha-1 yr-1. Green-Manure Cropping Systems

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Degradation of permanent grasslands can occur from accelerated soil erosion, compaction, drought, and salinization Strategies to sequester carbon in soil should improve quality of grasslands Strategies for restoration should include: Improved Grassland Management Enhancing soil cover Improving soil structure to minimize water runoff and soil erosion

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Improved Grassland Management Franzluebbers et al. (2001) Soil Sci. Soc. Am. J. 65:834-841 and unpublished data Establishment of bermudagrass pasture following long-term cropping in Georgia USA (16 °C, 1250 mm) Soil organic carbon sequestration rate (Mg ha-1 yr-1) (0-5 yr): -------------------------------- Hayed 0.30 Unharvested 0.65 Grazed 1.40

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Summary and Conclusions Greenhouse gas concentrations in the atmosphere are increasing and the threat of global change requires our attention A diversity of agricultural management practices can be employed to sequester more carbon in plants and soil Syntheses of available data are needed Gaps in our knowledge need to be researched Strategies to sequester soil carbon will also likely restore degraded land and avoid further degradation