HYDRAULIC REDISTRIBUTION AND IT’S POTENTIAL FOR FOOD PRODUCTION
Professor José Miguel Reichert Física do Solo- UFSM Sérgio Ely V. G. A. Costa WATER CYCLE
LimpoporakRAMSAR (2011) BLUE WATER VS GREEN WATER
INVISIBLE WATER
Hamdy (2008) BLUE WATER = SHARE OF WATER RESOURCES STORED IN RIVERS, LAKES AND GROUNDWATER THAT IS CONTROLLED BY PHYSICAL PROCESSES GREEN WATER= WATER THAT IS INFLUENCED BY BIOLOGICAL PROCESSES SUCH AS EVAPO-TRANSPIRATION BY VEGETATION AND STORED AS SOIL MOISTURE WATER USE
POPULATION CLIMATE TIME ECONOMY
INDICATOR ??????
“WITHDRAWALS-TO-AVALABILITY RATIO”
LONG TERM EFFECTS WATER AVAILABILITY
Fonte FEOW disponível em: http://www.feow.org WATER USE WATER USE SECTORS
ANNUAL WITHDRAWALS
Menzel & Matovelle (2010)
IRRIGATION GREEN WATER USE EFFICIENCY
100 90 80 Today 2030 70 60 50 40 30 20 10 0
(FAO, 2010) http://www.feow.org
EFFICIENCY
WITHDRAWALS IMPROVING WATER PRODUCTIVITY WHERE DOES THE RAINWATER GO ? RAIN RAINFALL PARTIONING
RF – (E+T+R+D) D= 10-30% R= 10-25% E= 30-50% T= 15-30% Hillel (2008) ROOT-ZONE WATER BALANCE
CHANGES IN STORAGE= GAINS – LOSSES 4-5 CROP YIELDS !!!! (ΔS + ΔV) = (P+I+U) – (R+D+E+T) GREEN GREEN WATERREQUIREMENT CROPOF % GREEN WATER REQUIREMENT GREEN WATER FLOW PRODUCTIVE WATERGREEN USE SOIL WATER RECHARGE SOIL WATER RAIN INPUT - BLUE WATER BALANCE % OF VAPOR FLOW FARMER’S FIELDFARMER’S GREEN WATER LOSS GREEN WATER YIELD GAP VAPOR PERCOLATION BLUE WATER RAIN DEFICIENCY LOSSES RUNOFF BLUE WATER Rockström et(2007) al. FLOW GREEN GREEN WATER RESOURCE BLUE WATER RESOURCE HYDROLOGICAL LIMITATIONS GLOBAL PRODUCTION LOSSES LOSSES TOTAL CEREAL VS IRRIGATED CEREALS
GREEN WATER USE EXCLSIVELY?!
WATER PRODUCTIVITY
Sieber & Döll (2010) WATER PRODUCTIVITY FOOD, FIBER PRODUCTION VS WATER CONSUMPTION CULTURE TYPE m-3 kg-1 m-3 1.000 k cal-1 CEREALS 1,5 0,47 STARCHY 0,7 0,78 ROOTS 600 m3 SUGARCROPS 0,15 0,49 OILCROPS 2 0,73 WATER PRODUCTIVITY VS GRAIN YIELD VEGETABLE 2 0,23 OILS VEGETABLES 0,5 2,07 AVERAGE 1,14 0,5 EUCALYPTUS 0,6 MEAT 4 DAIRY >6 PRODUCTS VAPOR SHIFT !!!! WATER PRODUCTIVITY
WP= green WP m-3 t-1 (ET flow) WP= WP -3 -1 t WPt = productive green WP m t (T (1- ebY ) flow) b= constant (rate of decline in E) Y= grain yield (t ha-1)
ETo = reference evapotranspiration (mm day-1) Δ= slope of vapor pressure curve (kPa 0 C-1 ) ϒ= psychrometric constant (kPa 0 C-1 ) Shuttleworth (1993) Rn= net radiation at crop surface (mm day-1 ) G= soil heat flux (mm day-1 ) SOIL – PLANT - ATMOSPHERE DELTA FLOWS
Δ1
Δ2 Δ
Δ3 DELTA FLOWS DAILY CHANGES
ROOT AGING
Nobel (2009)
DRYING DELTA FLOWS
Höfler-Thoday Diagram
Water Transport speed potencial gradient
Membrane
Water potencial (MPa) potencial Water hydraulic conductivity
Relative water content ɵ
Half-time (seconds) DELTA FLOWS
Water liters per day
SOIL ROOTS LEAFS ATMOSPHERE
MASS FLUX OR MASS FLUX DIFFUSION OSMOTIC
PUSHED OR PULLED
TAIZ & ZEIGER (2009) DELTA FLOWS
ANALOGY TO OHM’S LAW
DIFFERENCE BETWEEN ELECTRIC AL POTENCTAL FLUX RESISTANCES
VOLTAGE FLUX RESISTANCES DELTA FLOWS
[LEAF VAPOR] – [ATMOSPHERE VAPOR] TRANSPIRATION LEAF + AIR RESISTANCE
VPDLEAF-AIR TRANSPIRATION LEAF + AIR RESISTANCE
VPD HIGHEST GRADIENT SOIL-PLANT-ATMOSPHERE DELTA FLOWS
DIEL VDPLEAF-AIR FLUCTUATIONS
LEAF AIR
VDP
CVAPOR = CONSTANT
MOURNING AFTERNOON
DAY PERIOD TAIZ & ZEIGER (2009) DELTA FLOWS
STOMATAL ROUTE SHORT TERM REGULATION LEAF AIR
CUTICULAR ROUTE
R folha= (Rm + Re)(Rc) Rm+Re+Rc
CO2 vapor
vapor CO2 WATER DRIVING FORCE
vacuole cell wall cell membrane
chloroplast cytoplasm
CR P(Mpa)
Air Water surface tension Water film Air-water interface curvature radius (CR)
Cellulose microfiber DELTA FLOWS
ROOT XYLEM LEAF XYLEM
LONGEST ROUTE
MASS FLUX IN CILINDERS
(VOLUME/TIME) DELTA FLOWS
“ AIR SEEDING”
EFFICIENCY
HOWEVER!!!!! V
TRACHEIDS VESSEL MEMBERS WATER MOVEMENT THROUGH PLANTS
VULNERABILITY TO EMBOLISM LOSS HYDRAULIC CONDUCTANCE HYDRAULIC LOSS
XYLEM WATER POTENCIAL SOIL- ROOT INTERFACE
SOIL ROOT XYLEM
WATER POTENTIAL
TRANSPIRATION
MASS FLUX OSMOTIC FLUX SOIL- ROOT INTERFACE
Time )
Root superficial area
Soil - root delta pressure
Soil-root cylinder radius
Hydraulic conductivity Ʃ effects soil interface root
SOIL- ROOT INTERFACE
)
1
-
Mpa
1 -
soil soil
gap root COMPACTION?!
overall Hydraulic Hydraulic conductance or conductivity (ms Soil drying time (days) HYDRIC STRESS SITUATIONS LEADING TO LOW WATER AVAILABILITY
HIGH VDP HIGH EVAPOTRANSPIRATION SALINITY FREEZING
GROWTH
CELULAR EXPANSION RATE CELL WALL EXTENSIBILITY HYDRAULIC PRESSURE CELULAR EXPANSION CELL WALL THRESHOLD RATE HYDRAULIIC REDISTRIBUTION
HYDRAULIC REDISTRIBUTION WATER MOVEMENT FROM RELATIVELY MOIST TO DRY SOIL LAYERS USING PLANT ROOTS SYSTEMS AS CONDUITSDRY LAYER
WET LAYER
30 HYDRAULIC REDISTRIBUTION
• LABORATORY TRIALS – ROOTS EXPELLING WATER IN DRIER LAYERS • REDISTRIBUTIO OCCURS IN ALL DIRECTIONS- GRADIENT
1987 (RICHARD & CALDWELL)
31 PROCESS EFFICIENCY
14 – 33% DAILY EVAPOTRANSPIRATION
50% - 100 days year-1
ROOT ARQUITECTURE + ROOT LENGTH DENSITY
Acacia tortilis 32 GRAIN PRODUCTION
RAZÃO DE TRANSPIRAÇÃO = ÁGUA TRANSPIRADA/CO2 ASSIMILADO
ESPÉCIES RAZÃO DE TRANSPIRAÇÃO C 3 500 INTEGRATED C 4 250 SYSTEMS CAM 50
33 BIOIRRIGATION
RESISTANCE TO DRY SPELLS
34 “IS IT PROBLEMATIC, FROM A WATER RESOURCES PERSPECTIVE, IF PEOPLE USE CROPS PRODUCED WITH ALMOST EXCLUSIVELY GREEN WATER? MAYBE, IT IS NOT, UNLESS CROP PRODUCTION LEADS TO WATER POLLUTION”
Siebert (2010) THANK YOU !