2242-13 Joint ICTP-IAEA Workshop on Uncovering Sustainable Development CLEWS; Modelling Climate, Land-use, Energy and Water (CLEW) Interactions 30 May - 3 June, 2011 The Use of Nuclear Techniques in Land and Water Management NGUYEN Minh-Long IAEA Vienna Internationa Centre Joint FAO IAEA Division, P.O. Box 100, Room A2270, 1400 Vienna AUSTRIA
Joint ICTP IAEA Workshop on Uncovering Sustainable Development The Use of Nuclear Techniques in Land and Water Management Long Nguyen NAFA (AGE) Atoms for Food and Agriculture: Meeting the Challenge
Corporate Mission Atomic energy for peace, health and prosperity Sustainable agricultural development, improved nutrition and food security to contribute to sustainable food security and safety by use of nuclear techniques and biotechnology
Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture FAO Agriculture and Consumer Protection Department AGE (NAFA) IAEA Department of Nuclear Sciences and Applications Soil Water Management and Crop Nutrition (SWMCN) Section Plant Breeding and Genetics (PBG) Section Animal Production And Health (APH) Section Insect Pest Control (IPC) Section Food & Environment Protection (FEP) Section SWMCN Laboratory PBG Laboratory APH Laboratory IPC Laboratory FEP Laboratory
Our Goals: Food Security Food Safety Sustainable Agriculture
Main Drivers: Sustainable management of agricultural resources: Sustainable Agriculture Adaptation-Mitigation of climate change
Implementation SWMCN Section Vienna International Centre Development, implementation and coordination of Coordinated Research Projects (CRPs). Support to Technical Cooperation Projects (TCPs). SWMCN Laboratory - Seibersdorf Develop and test new methodologies (R&D). Support to CRPs and TCPs. Develop training courses & fellowship training. Providing analytical support & external quality assurance.
SWMCN Soil Isotopic and nuclear techniques Crop Nutrition Water
SWMCN Activities Soil management and conservation for sustainable agriculture and environment agroforestry; conservation agriculture; reduced tillage. Technologies and practices for sustainable use and management of water in agriculture Enhance water use efficiency by crops through better irrigation, improved soil moisture conservation etc. Integrated soil-plant approaches to increase crop productivity in harsh environments Optimize production of drought and salt-tolerant crops. Nutrient management and enhanced N fertilizer use efficiency
Sustainable Agriculture WATER Agro-forestry Drought/salinity resistant crop genotypes SOIL Sustainable Agriculture PLANT Erosion monitoring & control Applied Nutrients Integrated water management Integrated soil fertility management
Soil fertility Soil Water Plant nutrition Soil physics Soil erosion
Integrated Soil-Water-Nutrient-Plant Management Plants (BNF, drought tolerant) Fertilisers. Organic residues Irrigation Soil physics Soil fertility Soil water
SWMCN Soil ENERGY CLIMAT E Crop Nutrition Water
Soil-Water-Crop Nutrition Management Technical basis Both stable and radioactive isotopes can be used as tracers in soil and water management & crop nutrition. Isotopes are atoms with: the same chemical properties the same number of protons and electrons. different number of neutrons and mass number (atomic weight). Isotopes can be either stable or radioactive stable isotopes: different masses ( 18 O and 16 O). radioactive isotopes: radioactive decay ( 32 P).
ISOTOPES Emitting ionizing radiation. Atoms A Z X A = Mass number (Atomic weight) = protons + neutrons Z = Atomic number = protons = electrons Isotopes Same chemical properties. Different mass number and different neutrons. Same protons and same electrons
Carbon (C) A (Atomic weight) Z (Atomic number) N Pro + neutron Proton = electron Neutron 12C 12 6 6 13C 13 6 7
Carbon (C) A Z N 10C 10 6 4 11C 11 6 5 12C 12 6 6 13C 13 6 7 14C 14 6 8
Hydrogen (H) A Z N 1H 1 1 0 2H 2 1 1 3H 3 1 2
Oxygen (O) A Z N 16O 16 8 8 17O 17 8 9 18O 18 8 10
Nitrogen (N) A Z N 13N 13 7 6 14N 14 7 7 15N 15 7 8
Phosphorus (P) A Z N 31P 31 15 16 32P 32 15 17 33P 33 15 18
Sulphur (S) A Z N 32S 32 16 16 33S 33 16 17 34S 34 16 18 35S 35 16 19 36S 36 16 20
Radioactive isotopes- Half life Important consideration in study planning: 32P: 33P: 35S: 87.4 days Activity (dpm): measured by liquid scintillation counter. Solvent: toluenne Scintillator: PPO (diphenyl oxazol) o POPOP (phenyloxazol-2-yl benzene). Quenching curve
Radioactive isotopes Examples: 32 P and 35 S. Specific activity: Bq/g of P or Bq/g of S in materials (soils/ plants/fertilisers). 1Bq=1dps and 1 Ci =3.7 x 10 10 dps Activity (dpm): measured by liquid scintillation counter. Solvent: toluenne Scintillator: PPO (diphenyl oxazol) o POPOP (phenyloxazol-2-yl benzene). Quenching curve
Converting dpm to specific activity Activity (dpm): measured by liquid scintillation counter. Actual activity (corrected for radioactive decay) Rate of decay of any radioisotope obeys exponential law: A o = A /e (-λt) where A is uncorrected dpm at time t, A o is dpm at time t =0 corrected for radioactive decay from D0 of the application of radioactive materials, and λ is decay constant, which is equivalent to 0.693/half life. e is the natural logarithm The corrected dpm is then converted to specific activity: Spac (μci/g of S or P)= corrected dpm / [amount of sample analysed (g) x concentration (μgs/g material) x 2.22]. 1 μ Ci =2.22 * 10 6 dpm
Stable isotopes Some commonly used stable isotopes and their relative proportions: Stable isotopes Element Heavy Light H 2 H (0.0156%) 1 H (99.9844%) N 15 N (0.366%) 14 N (99.634%) C 13 C (1.108%) 12 C (98.892%) O 18 O (0.204%) 16 O (99.759%)
Atom% abundance Natural abundances of some stable isotopes in atom % 99.985 % 1 H 0.015 % 2 H 98.892 % 12 C 1.108 % 13 C 99.6337 % 14 N 0.3663 % 15 N 99.759 % 16 O 0.0374 % 17 O 0.2039 % 18 O 95.018 % 32 S 0.767 % 33 S 4.215 % 34 S
Stable isotopes Atom% N15: Mass spectrometry or emission Atom% N15= number of N15 atoms/ number of N atoms. Atom%N15 excess= Atom% N15-0.366. (100 atoms of N in atmosphere, there are only 0.366 atoms of N15 and 99.64 atom of N14). Ndff%=atom%N15 excess in plant materials/ atom %N15 excess in N15-labelled fertilizer
Atom% abundance Isotopic abundance is the number of atoms of a particular isotope of an element as a fraction of the total number of atoms of that element. It is usually expressed as a percentage and noted as atom%. 90 atoms 14 N + 10 atoms 15 N. 100 atoms N.. 10 atom% 15 N
Enrichment delta, δ
Enrichment delta, δ Isotope Ratio International Reference Standard Hydrogen D/ 1 H = 0.00015576 Standard Mean Ocean Water, SMOW Carbon 13 C/ 12 C = 0.0112372 Pee Dee Belemnite, PDB Nitrogen 15 N/ 14 N = 0.0036765 Air Oxygen 18 O/ 16 O = 0.0020671 PDB Oxygen 18 O/ 16 O = 0.0020052 Standard Mean Ocean Water, SMOW Sulfur 34 S/ 32 S = 0.0450045 Canyon Diablo Troilite Meteorite, CDT
Measurement of stable isotopes Isotopes have slightly different physical properties. Detection methods uses one of this properties (mass, emission spectrum, IR absorption ). The most common method to measure stable isotopes is mass spectrometry. Mass spectrometers capable of measuring the stable isotope ratios of light elements (H, C, N, O and S) are called Isotope Ratio Mass Spectrometers (IRMS). New methods based on IR absorption have been introduced recently.
Mass spectrometry Mass spectrometry is an analytical technique in which atoms or molecules from a sample are ionized, separated according to their mass-to-charge ratio (m/z), and then recorded.
Picarro L1115-i water vapor analyzer Precision δ 18 O <0.1 Precision δ D <0.5 Simultaneous measurement of δ 18 O and δd Continuous, real time measurements flow throw cell of 30ml/min reading every 6 sec. Liquid water measurements by means of a vaporizer Field and laboratory deployable No vacuum; dry air as carrier gas; no consumables Low drift
Water vapor sampling
Beijing Field Campaign June 2009
Water isotope analyzer with liquid water injector Field deployable water vapour isotope analyzer
Nuclear techniques used in SWMCN Management Fallout radionuclides 14 N 32 P 31 P 31 P 15 N 13 CO 2 Soil moisture neutron probe 12 CO 2 15 N 14 N 32 P 18 O 13 CO 2 12 CO 2 16 O 18 O 16 O 13 C 12 C
Carbon isotopes in crop water productivity assessment Plants can be grouped according to 13 C discrimination 12 CO 2 (99%) C3 plants: δ 13 C = -26 C4 plants: δ 13 C = -12 13 CO 2 (1%) rice, wheat, forest, vegetation maize, sorghum, sugarcane, some tropical herbs
Fallout radionuclides Adapted from Walling, 2007 Key Features of the Approach RETROSPECTIVE SINGLE SITE VISIT SPATIALLY DISTRIBUTED Pb 210ex 100years Cs 137 50 years Be 7 1 2 months
Radionuclide in soil erosion-conservation FRN with precipitation (P) Erosion site 137 Cs < P Resulting soil level Deposition site 137 Cs > P Original soil level
Isotopic and nuclear techniques in soilwater-crop nutrition Enhance sustainable use of soil-water-nutrient resources. Quantify biological nitrogen fixation. Minimize effects of soil erosion and degradation. Enhance water use efficiency by crops. Optimize production of drought and salt-tolerant crops. Evaluate effects of crop residue incorporation on land productivity and food security. Improve water (nutrient) use efficiency thus minimize losses beyond the plant rooting zone.
Examples of major outcomes 41 countries use nuclear techniques to assess soil erosion and develop cost-effective soil conservation measures. China, Morocco, Romania and Vietnam have effectively reduced soil erosion rates by 55-90%. 95 Member States use isotopic and nuclear techniques to identify land and water management practices to improve nutrient and water use efficiency (WUE). Some outcomes: At least 25-50% 50% increase in yield, WUE and revenue through efficient soil moisture monitoring and irrigation in Chile, Jordan, Syria, Turkey and Uzbekistan. 30% increase in BNF through improved soil-water water- nutrient-crop management practices in Asia and Africa.
Schematic of a riparian buffer zone-wetland Agricultural land Riparian zone Terrestrial-aquatic ecotone River surface runoff riparian vegetation water table subsurface runoff
Nitrate removal processes in riparian zones Agricultural land Riparian zone Terrestrial-aquatic ecotone River AtmosphericN 2, N 2 O water table Plant uptake Plant N Denitrification N 2, N 2 O Nitrate (NO 3 ) Immobilisation Dissimilatory reduction to ammonium (DNRA) Microbial N NH 4
Nitrate transformation processes DENITRIFICATION (microorganisms) N GASES (ATMOSPHERE) DNRA (DISSIMILATORY NITRATE REDUCTION TO AMMONIUM) (microorganisms) AMMONIUM N (SOIL OR WATER) IMMOBILISATION (microorganisms) MICROBIAL N (SOIL MICROBES) PLANT UPTAKE (plants) PLANT BIOMASS N (PLANTS)
Plants have a dual role - direct uptake - influencing other processes Microbial N Transformations organic carbon oxygen DENITRIFICATION DNRA IMMOBILISATION
Riparian wetland
Microcosm experiment Without plants With plants
Injecting 15 NO 3 -N - 4 points - 1 cm intervals from 0-14 cm depth (microcosms 15 cm deep)
N pool measured Process Soil 15 NH 4 -N DNRA 15 NO 3 -N Soil 15 Organic N Plant 15 N Immobilisation Plant uptake Unaccounted 15 N Denitrification
TRANSFORMATION PROCESS WITH PLANTS WITHOUT PLANTS % 15 NO 3 -N TRANSFORMED Denitrification 61 29 DNRA <0.1 49 Immobilisation 24 22 Plant uptake 15 -
Differences in soil oxidation oxygen 0-0.4 Depth below soil surface (cm) -0.8-1.2-1.6 With plants Without plants -2 0 20 40 60 80 100 Oxygen saturation (%)
Differences in soil oxidation redox 0-2 -4 Depth -6 below soil -8 surface (cm) -10 With plants Without plants -12-14 100 150 200 250 300 350 Redox potential (mv)
Conclusions ** Vegetation important influence on N transformation and removal ** Denitrification/sustainable N removal enhanced by vegetated/moderately anoxic soil (redox ~200 mv) ** N retention (DNRA) favoured by unvegetated/highly anoxic soil (redox ~150 mv or less)
Seibersdorf Laboratories Capacity Building - Training course and individual training
Training in Soil Water Management
Training Courses field trip
Current issues/challenges Land Degradation Water Management Abiotic Stress Crop Nutrition Salinity
SWMCN Laboratory Activities Soil Management (2.1.1.1) Adaptation to Water Management Abiotic Stress (2.1.1.5) (2.1.1.2) Analysis
SWMCN projects 2.1.1.1. Soil management and conservation for sustainable agriculture and environment. 2.1.1. 2. Technologies and practices for sustainable use and management of water in agriculture 2.1.1.5. Integrated soil-plant approaches to increase crop productivity in harsh environments
CRPs in Soil Management (2.1.1.1) Area-wide Precision Conservation to Control the Impacts of Agricultural Practices on Land Degradation and Soil Erosion (D1.20.11) Integrated Soil, Water and Nutrient Management in Conservation Agriculture (D1.50.09
CRPs in Water Management (2.1.1.2) Strategic placement and area-wide evaluation of water conservation zones in agricultural catchments for biomass production, water quality and food security (D1.20.10) Managing irrigation water to enhance crop productivity under water-limiting conditions (D1.20.09)
CRPs in Crop Nutrition-Abiotic stress (2.1.1.5) Selection and Evaluation of Food (Cereal and Legume) Crop Genotypes Tolerant to Low Nitrogen and Phosphorus Soils (D1.50.10)
Adaptation Area-wide Sustainable Land Management: To enhance soil resilience and minimize soil erosion and degradation. Enhance water use efficiency by crops through better irrigation, improved soil moisture conservation and nutrient management, and change in cropping intensity. Optimize production of drought and salttolerant crops. Integrated cropping-livestock production systems
Mitigation Enhancing soil carbon sequestration. Integrated S-W-N in both cropping and grazing lands. Restoration of degraded lands. Land use changes (agroforestry; cropping to grasslands; conservation agriculture; reduced tillage) Reducing GHG emissions CH 4 and N 2 O: Higher GWP (global warming potential) than CO2 (21 and 310 times). Enhanced N fertilizer use efficiency
International Symposium on Managing Soils for Food Security and Climate Change Adaptation and Mitigation 23-26 July 2012 Vienna, Austria Soil and Water Management & Crop Nutrition Subprogramme http://www-naweb.iaea.org/nafa/swmn/index.html