Soil Carbon Pool as an Environmental Indicator Rattan Lal Carbon Management and The Ohio State University Columbus, OH 43210 USA 1
SOIL: THE ESSENCE OF LIFE Hello there folks. Do you know who or what I am? I am the geomembrane of the Earth. I am your protective filter, your buffer, your mediator of energy, water, and biogeochemical compounds. I am your sustainer of productive life, your ultimate sources of elements, and the habitat for most biota. I am the foundation that supports you, the cradle of your myths, and the dust from which you will return. I am a soil. Richard Arnold (2005) Senior Soil Scientist 2
SOIL Soil is a 4-dimensional complex mixture of organic and mineral substances, with a hierarchy of pores containing dilute solution and gases at a wide range of energy potentials, comprising of diverse micro to macro organisms, and a medium for complex biochemical transformations which support plant growth and numerous ecosystem services. Lal (2015) 3
THE DIRT "Dirt has no currency in western society, and has little impact on politicians. It comes under the journalist "MEGO" category My Eyes Glaze Over. Bar a few impressive dust storms, we care little of our soil. We do not relate what we eat in our home, buy in out supermarkets, or drink from our Starbucks to the soil. And yet, without soil, we become thirsty, hungry, and we die. Without soil, we become Mars, with no water, no atmosphere, and only relics of life, with at best distant stargazers trying to figure out the life that could have been." Young and Crawford (2015) 4
SCIENCE POLICY INTERPHASE "So, before we examine what we need in terms of new seeds, new chemicals to add to the soil, and new technology platforms that need development, we need to urgently look at legal frameworks that protect our soil asset. So, our first challenge with any discipline, any agricultural framework, or any plant species, is to call on governments to implement legal strategies to secure and build our fertile soil reserves." Young and Crawford (2015) Especially so during the IYS-2015 5
Mamani-Pati et al., 2014 6
NATURAL ENVIRONMENT Physical Chemical The aggregate of surrounding things, conditions, or influences Interaction Surroundings Milieu Biological Context The style of a place 7
INDICATOR Latin verb indicare means to: Disclose Point out Announce Estimate Put a prince on communicate 8
INDICATOR It is a sign, signal or a message about the surroundings. It is an acceptable and simple yard stick about any parameter as a measure of the present state and of the future trends. It is a proxy regarding state of the things, resources, activities, etc. 9
ENVIRONMENTAL INDICATOR It is a measure, quantitative or qualitative, of changes occurring in the environment, including trends overtime It is a quantifiable measure of the sate of the environment, and its impact on ecosystems. 10
ENVIRONMENTAL INDICATOR Ecosystem Economy Human Well-being 11
CHARACTERISTICS OF A GOOD INDICATOR Relevant Simple Reliable Repeatable Accessible Quantifiable Credible Scalable: local to national and global User-driven Policy-relevant Highly aggregated 12
APPLICATION OF INDICATORS Assess trends Compare scenarios Monitor progress Evaluate performance Provide early warning Assist in decision making Identify knowledge gaps Define researchable issues Establish criteria for resource allocation Measure impact 13
GROUPING OF INDICATORS Types of Environmental Indicators State of the Environment Indicators Sustainability Indicators Environment Performance Indicators 14
INTERACTIVE INDICATORS Environment Gaseous emissions Sea level rise Biodiversity Water quality Air quality Soil quality Human Well being Average age Education Diet quality Affluence Status of women and minority Types of Indicators Sustainability Per capita CO 2 emission Renewable vs. total energy consumed Recycling of urban/ industrial/ ethnic/ gender equity Resilience Performance Trend in emissions Renewable resources vs. total resources Intensity of use 15
SUSTAINABILITY INDICATORS Social Well-being Sustainability Economy Environment 16
HOLISTIC INDICATORS Environment Economy Society Sustainability Technology Performance Management 17
SOIL CARBON AS AN ENVIRONMENTAL INDICATOR BECAUSE IT DETERMINES: Productivity Erosion, degradation Biodiversity Water quality Gaseous emission and air quality Pollutant denaturing Food and nutritional security Plant, animal and human health Ecosystem resilience Sustainability 18
Extractive Farming/Subsistence Depletion of SOC and Nutrients Decline in Soil Structure Loss of Soil Resilience Decline in Ecosystem Functions and Services Loss of Soil biodiversity Disruption of Key Processes Hunger Malnutrition Political Unrest Civil Strife War and insecurity Severe Degradation
THE LIVING SOIL Soil is an organiccarbon mediated realm in which solid, liquid, gas and biology all interact from a scale of nanometer to landscape. The weight of live organisms in arable land is 5 t/ha 20
SOILS AND MEN (1938) Carbon Management and SOM is one of our most important natural resources: its unwise exploitation has been devastating, and it must be given its proper place in any conservation policy as one of the major factors affecting crop production in the future. A declining soil fertility, due to a lack of organic material, major elements, and trace minerals, is responsible for poor crops and in turn for poor people. Health of our nation may be impossible to restore without first restoring the health of our soils. Albrecht, President SSSA (1938) 21
AL-IKSEER (THE RECIPE) Soil organic matter has over the centuries been considered by many as an elixir of life. Ever since the dawn of history, some eight thousand and more years ago, man has appreciated the fact that dark soils, commonly found in river valleys and broad level plains, are usually productive soils. He also realized at a very early stage that color and productivity are commonly associated with organic matter derived chiefly from decaying plant materials.... Allison, 1973 22
NUTRIENTS REQUIRED TO CONVERT BIOMASS INTO SOC Crop Residues SOC Biochemical Transformations + (N, P, S etc.) Elemental Ratio Cereal Residues SOC C:N 100 12 C:P 200 50 C:S 500 70 Straw photo: http://shannahatfield.com/2013/09/24/hay-vsstraw/ Humus photo: http://www.davecullen.com/ forum/index.php?topic=26820.3285 23
TRADING NUTRIENTS FOR CARBON Sequestration of 10,000 kg of biomass C as SOC requires additional nutrients: 833 kg N 200 kg P 143 kg S 28,000 kg of C in residues 62,000 kg of residues (oven dry) These ingredients will produce + 17,241 kg of humus Recalculated from Himes, 1998. 24
MRT OF SOIL ORGANIC CARBON MRT varies from a few seconds to a few millennia. It is only the SOC with a long MRT of decades to millennia that can mitigate the climate. It is the environmental and biological controls, rather than molecular structural properties (recalcitrance), which impact the MRT. 25
MECHANISMS OF SOC PROTECTION Protection Mechanism Chemical Physical Biochemical Unprotected Component Silt + Clay Micro-aggregates Non-hydrolyzable C POM in sand fraction Six et al. (2002) 26
WATER RESOURCES - Quality - Quan+ty CLIMATE CHANGE - Mi+ga+on - Adapta+on - Stabiliza+on THE ENGINE OF ECONOMIC DEVELOPMENT SOIL QUALITY (SOC) BIODIVERSITY - Above ground - Below ground FOOD SECURITY - Quan+ty - Quality 27
SOIL C SEQUESTRATION Innovative Technology II Relative Soil C Pool 100 80 60 40 Subsistence farming, none or low off-farm input soil degradation New equilibrium C Sink Capacity Rate ΔX Adoption of RMPs ΔY Maximum Potential Attainable Potential Δt Accelerated erosion Innovative Technology I Conservation Agriculture Biochar Agroforestry Desert. Control Afforestation Pasture Mgmt H 2 O harv., DSI Farming Systems 20 MRT = Pool Flux 0 Lal, 2004 20 40 60 80 100 120 140 160 Time (Yrs) 28
WORLD POPULATION (BILLIONS) 200.8 1 3 4 6 7.6 8 9.6 15 RELATIVE FOOD PRODUCTION (Mg/ha) 12 8 6 4 1 0.8 TECHNOLOGICAL INNOVATIONS Hand Tools Animal Power Rotations GREEN REVOLUTION Machine power Fertilizers Germplasm Improved cultivars Biotechnology No-till farming INM IPM Carbon sequestration Conservation agriculture Micro-irrigation Precision farming Perennial culture Complex rotations GMOs Sustainable intensification (SI) Rhizospheric processes Diseasesuppressive soils Soil-less agriculture The nexus approach Phytobiome management Recarbonization of the biosphere Nutritionsensitive agriculture SI/ Restorative Agriculture Soil-less agriculture Phytobiome management Urban agriculture Space farming 1750 1850 1950 1975 2000 2015 2025 2050 YEAR 29
TOWARDS C- NEUTRAL AGRICULTURE INM No-till Farming Chatting with plants through molecularbased signals N, P, K, Zn, H 2 O Soil biota and ecosystems services 30
Resilience of Soil-Ecological Systems It has multiple regimes (stable states) which are separated by thresholds Resilience Thresholds The current state of the system Possible states in which the system can still have the same function Critical Threshold Irreversible Degradation Regime Shift 31
THRESHOLD/CRITICAL LEVEL Threshold/Critical Level/Tipping Point: Soil processes and properties have threshold levels (~2.0% SOC concentration). Beyond threshold level, there is a drastic regime change. 32
CRITICAL LEVEL OF SOC FOR WHEAT YIELD (Diaz-Zorita et al., 2002) 4000 Yield (kg ha -1 ) 3000 2000 1000 0 0 20 40 60 80 Soil Organic C (Mg ha -1 ) 33
CROP YIELD INCREASE WITH INCREASE IN SOC BY 1 Mg C/Ha (LAL, 2005) Crop Yield Increase (Kg/Ha/Mg C) Maize 100-300 Soybeans 20-50 Wheat 20-70 Rice 10-50 Sorghum 80-140 Millet 30-70 Beans 30-60 30-50 million tons/yr in developing countries 34
SUSTAINABLE SOIL MANAGEMENT Replace what is removed, Respond wisely to what is changed, and Predict what will happen from anthropogenic and natural perturbations 35
SOIL C AS AN INDICATOR OF ENVIRONMENT There are numerous advantages: 1. It is a familiar property, 2. It involves direct measurement, 3. It can be measured in 4 dimensions (length, width, depth, time), 4. It lends itself to repeated measurements over the same site, 36
SOIL C AS AN INDICATOR OF ENVIRONMENT (CONTINUED) 5. It is linked to ecosystem performance and services, 6. It is a key driver of soil formation, 7. It is important to soil fertility, 8. It has memory, 9. It has well defined properties, 37
SOIL C AS AN INDICATOR OF ENVIRONMENT (CONTINUED) 10. It can be used in synergism with other indicators, 11. Its uncertainty can be quantified, 12. Its pathways across the landscape can be followed, 13. It is an important archive of paleo-environmental conditions. 38
SOILS AND MEN (1938) Carbon Management and SOM is one of our most important natural resources: its unwise exploitation has been devastating, and it must be given its proper place in any conservation policy as one of the major factors affecting crop production in the future. A declining soil fertility, due to a lack of organic material, major elements, and trace minerals, is responsible for poor crops and in turn for poor people. Health of our nation may be impossible to restore without first restoring the health of our soils. Albrecht, President SSSA (1938) 39
AL-IKSEER (THE RECIPE) Soil organic matter has over the centuries been considered by many as an elixir of life. Ever since the dawn of history, some eight thousand and more years ago, man has appreciated the fact that dark soils, commonly found in river valleys and broad level plains, are usually productive soils. He also realized at a very early stage that color and productivity are commonly associated with organic matter derived chiefly from decaying plant materials.... Allison, 1973 40
GLOBAL SOIL ORGANIC CARBON POOL 0-30cm DEPTH Total Pool = 684-724 (704) Pg... Batjes (1996) 0.4% Increase/yr = 2.8 Pg C/yr 41
GLOBAL POTENTIAL OF TERRESTRIAL C SEQUESTRATION (Lal, 2010) 42
THE NPP OF A CORN FIELD IS 400 TIMES THE ANNUAL Carbon Management and INCREASE IN ATMOSPHERIC C POOL + 2 ppm CO2/y 5 x 10-9 Pg C/ha per yr NPP 12.5 x 10-12 Pg C/ha/y NBP 3PgC/yr 43
THE TERRESTRIAL AND OCEANIC PROCESSES IMPACTING ATMOSPHERIC CHEMISTRY Atmosphere 800 Pg (400 ppmv) + 4.3 Pg/yr (2.2 ppm/yr) Land Fossil Fuel Ocean 44
POTENTIAL MITIGATION STRATEGIES INVOLVING THE TERRESTRIAL BIOSPHERE Terrestrial Biosphere Soil Biota Atmosphere Fossil Fuel Ocean 45
Biosphere Live Biomass Detritus Material Marine Biota Green Roofs Afforestation Lithosphere Geologic sequestration (CCS) Carbonation processes Weathering of alumino-silicates Storing Biogenic Carbon Anthroposphere Byproducts of Biomass Houses, furniture, timber Carbonization Landfills Artificial trees Pedosphere Land application of biomass-c (mulch, compost, manure, biochar) Erosion control Waste management Producing technosols Soil restoration 46
TECHNICAL POTENTIAL OF CARBON SEQUESTRATION IN THE Activity TERRESTRIAL Technical Potential (Pg C/yr) A. Soil Cropland management 0.4-1.2 Restoration of Salt-Affected Soils 0.3-0.7 Desertification Control 0.2-0.7 Sub-total 0.9-2.6 B. Vegetation Afforestation, Forest Succession, Agroforestry, Peatland Restoration 1.2-1.4 Forest Plantations 0.2-0.5 Savanna and Grassland Ecosystems 0.3-0.5 Sub-total 1.7-2.4 Grand Total 2.6-5.0 (3.8) 47
4 FOR 1000 : A NEW PROGRAM FOR CARBON SEQUESTRATION IN AGRICULTURE With soil C pool of 2400 Pg, 4/1000 = 9.6 Pg C = 4.5 ppm CO 2 Drawdown Reducing emissions in 2050 to half of 1990 levels in Europe implies offsetting a total if 20 Pg CO 2 (5.5 Pg C) Thus, 4 per 1000 initiative can be an important strategy to achieve this goal. 48
SOIL CARBON AND ECOSYSTEM SERVICES 2 - Food Security 1- Global Soil C Pool Lal (2012) 49
Carbon Management and SOIL: THE GLOBAL ICON www.seeturtles.org HANDOUT / Reuters Water Carbon Nitrogen Phosphorous Sulfur Lal (2014) www.worldwildlife.org 50 en.wikipedia.org