crops (wheat, corn, & rice) in the irrigated areas: an ... · crops (wheat, corn, & rice)...
TRANSCRIPT
Daniel J. Foley a,b
Prasad S. Thenkabaila,Itiya P. Aneecea, Pardhasaradhi G. Teluguntla a,b, & Adam J. Oliphant a
GFSAD (Global Food Security-Support Analysis Data at 30 m)
PECORA October 8, 2019 Baltimore, MD
aWestern Geographic Science Center, USGS, Flagstaff, AZ, USAbBay Area Environmental Research Institute, Moffett Field, CA, USA
A Meta-Analysis of Global Crop Water Productivity of 3 Leading World
Crops (Wheat, Corn, & Rice) in the Irrigated Areas: An Assessment from
Remote Sensing & Non-Remote Sensing Studies Over 3 Decades
Introduction: Addressing the Global Food Security Challenge
Next 50 years World needs to meet the food demand of a
population which will grow from 7 billion in year 2011 to 9 or
10 billion by 2050. There is a consensus view that:
1. Increasing cropland areas is NOT a solution;
2. Increasing water allocations (more irrigation) is
NOT a solution.
It is critical to increase food production that is ecologically & environmentally friendly with:
(a) less croplands, and
(b) less water allocations for croplands
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Problem and the Need
Big Picture, Background
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U.S. Department of Interior
Problem: Looming Global Food Crisis1. Population will reach about 10 billion by 2050
2. Cropland areas have stagnated
3. Water is increasingly limited (has multiple demands)
4. Green revolution (productivity per unit of land,
irrigation expansion, cropland intensification): has stagnated
Big question:So, how are we going to address food security of the World in the 21st Century?
Solution:A. Blue revolution (productivity per unit of water) focus;
B. Cropland management (crop types, overcoming salinity, less bio-fuels) focus;
C. Technology (desalinization, bio-technology); and
D. Smart choices (food habits, waste habits)
Challenge: How can we continue to produce more food for ballooning
populations using existing croplands and existing water
allocations?
Background:
1. Will there be enough water to grow
food?
2. Will the water be available when it is
needed (e.g., during the growing
period)?
3. What happens if the fertile croplands
are taken for urban development?
4. Can we grow enough food by
addressing environmental\health
concerns?
Image: Grid-Arendal
Critical Questions to Address Food Insecurity
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Background:
U.S. Geological Survey
U.S. Department of Interior
Crop Water Productivity of Irrigated Croplands of the World (kg\m3)
Definition
Crop Productivity (kg/m2)
CWP (kg/m3) = -------------------------------------
Water use (m3/m2)
Phyiscal Crop Water Productivity* (CWP) (kg/m3)
Crop Productivity in units of biomass (kg/m2)
Water use in units of (m3/m2)
Help us answer:
1. Crop per drop: How much crop per drop ?
2. Pin-point areas: Where are areas of high, low, intermediate CWP?
3. Areas to improve CWP: What areas are under low and high CWP.
…increasing crop WP will help us achieve blue revolution.
Definition:
Credits: Thenkabail et al.
Crop Water Productivity (kg/m3) Definition
*Note: there are other definitions such as nutritional CWP and economic
CWP; but for our purposes, this is most apt, also most widely used
U.S. Geological Survey
U.S. Department of Interior
U.S. Geological Survey
U.S. Department of Interior
Crop Water Productivity of Irrigated Croplands of the World (kg\m3)
Goal & Research Questions
▪ Goal: Comprehensive meta-analysis on the variability of Crop Water Productivity (CWP) of Irrigated Croplands of the World
▪ Geospatial relationships of wheat, corn, & rice CWP relative to:
1. Climate
2. Latitude
3. Soil
▪ Major Research Questions :
▪ What is the current state of CWP for these crops?
▪ How does CWP of these crops vary in space and time?
▪ Which areas have high, moderate, or low CWP?
▪ What are the causes for such variability?
▪ Where are the best opportunities for increasing CWP?
Goal & Research Questions:
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U.S. Geological Survey
U.S. Department of Interior
Crop Water Productivity of Irrigated Croplands of the World (kg\m3)
Data for Meta-Analysis
• 148 different
measured CWP sites
for wheat, corn, & rice
• 111 published studies
of irrigated areas
relative to 6 variable
combinations:
1A) Climate
1B) Latitude
1C) Soil
1D) Latitude & Soil
1E) Latitude & Climate
1F) Climate & Soil
Summary of Crop Water Productivity of Irrigated
Croplands of the World database.
Data for Meta-Analysis from Published Studies:
U.S. Geological Survey
U.S. Department of Interior
Crop Water Productivity of Irrigated Croplands of the World (kg\m3)
Methods
Part 1: Global geospatial mapping
Part 2: Statistical Analysis
▪ Part A: Climate
▪ Part B: Latitude
▪ Part C: Soil
▪ Part D: Latitude-Soil
▪ Part E: Latitude-Climate
▪ Part F: Climate-Soil
▪ Part G: Country CWP▪ G.1 Wheat
▪ G.2 Corn
▪ G.3 Rice
▪ Part 3: Water Savings Analysis
Soil
Climate
Latitude
CWP data for
wheat, corn, &
rice
Methods, Part 1-3: Spatial and Statistical Analysis
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1A) Köppen-Geiger Climate Classification
1B) FAO Soil-Type
1C) Latitude 10° Zones
Methods Part 1: Spatial Mapping of CWP
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U.S. Department of Interior
Methods Part 2: Statistical Analysis of CWP
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U.S. Department of Interior
1. Statistical tests of significant differences with R programming software
■ Chosen for its reproducible high-quality analysis. Climate classifications, latitude
zones, & soil-types ( n ≥ 5) + CWP values were analyzed
2. Crop datasets statistically tested
■ For normality, skewness, kurtosis, and homogeneity of variance. Determined if
Analysis of Variance (ANOVA) assumptions were met
3. Non-parametric Kruskal-Wallis one-way ANOVA
■ Due to unbalanced sample sizes, ranks for testing whether CWP values differed
significantly across variables. Account for unequal sample sizes between group.
4. Mean CWP values tested for statistical difference by geospatial variable
■ At 90%, 95%, and 99% confidence intervals for:
(1) climate classification, (2) latitude zones,
(3) soil-types, (4) latitude and soil-type,
(5) latitude and climate, & (6) climate and soil-type
• Method for calculating water use & saving potential developed
• Water that can be potentially saved for wheat, corn, & rice
estimated by increasing mean CWP per country by:
• 10%
• 20%
• 30%
• Calculations derived using CWP data along with FAO
statistical crop data including:
• area harvested in hectares (ha)
• grain yield (hg/ha) from each country
Methods Part 3: Water Savings Calculations (1/2)
U.S. Geological Survey
U.S. Department of Interior
▪ 𝐴) 𝐵𝑎𝑠𝑒 𝑚𝑒𝑎𝑛 𝐶𝑊𝑃𝑘𝑔
𝑚3 + (𝐵𝑎𝑠𝑒 𝑚𝑒𝑎𝑛 𝐶𝑊𝑃 𝑥 .10, .20,& .30
▪ 𝐵)𝐶𝑟𝑜𝑝 𝑃𝑟𝑜𝑑𝑢𝑐𝑖𝑡𝑖𝑣𝑡𝑦
𝑘𝑔
𝑚2
𝐶𝑊𝑃𝑘𝑔
𝑚3
= 𝑊𝑎𝑡𝑒𝑟 𝑢𝑠𝑒 𝑝𝑒𝑟 𝑎𝑟𝑒𝑎𝑚³
𝑚2
▪ 𝐶) 𝑇𝑜𝑡𝑎𝑙 𝑤𝑎𝑡𝑒𝑟 𝑢𝑠𝑒 (𝑚3) =
𝑊𝑎𝑡𝑒𝑟 𝑢𝑠𝑒 𝑝𝑒𝑟 𝑎𝑟𝑒𝑎𝑚³
𝑚2 𝑥 𝐴𝑟𝑒𝑎 ℎ𝑎𝑟𝑣𝑒𝑠𝑡𝑒𝑑 𝑚2
▪ 𝐷)𝑊𝑎𝑡𝑒𝑟 𝑠𝑎𝑣𝑖𝑛𝑔𝑠 (𝑚3) = 𝐵𝑎𝑠𝑒 𝑚𝑒𝑎𝑛 𝐶𝑊𝑃 𝑤𝑎𝑡𝑒𝑟 𝑢𝑠𝑒 −𝑤𝑎𝑡𝑒𝑟 𝑢𝑠𝑒 𝐶𝑊𝑃 𝑎𝑡 % 𝑖𝑛𝑐𝑟𝑒𝑎𝑠𝑒
▪ 𝐸) 𝑊𝑎𝑡𝑒𝑟 𝑠𝑎𝑣𝑖𝑛𝑔𝑠(𝑚3) 𝑐𝑜𝑛𝑣𝑒𝑟𝑡𝑒𝑑 𝑡𝑜 𝑏𝑖𝑙𝑙𝑖𝑜𝑛𝑠 𝑜𝑓 𝑙𝑖𝑡𝑒𝑟𝑠 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟
Methods Part 3: Water Savings Calculations (2/2)
U.S. Geological Survey
U.S. Department of Interior
U.S. Geological Survey
U.S. Department of Interior
Crop Water Productivity of Irrigated Croplands of the World (kg\m3)
Results
• Global area distribution of wheat, corn, & rice
percentage1,2.
Map of sites with measured CWP values used in this study & corresponding countries represented.
Results Part 1: CWP Mapping Wheat, Corn, & Rice
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Results Part 1: CWP Köppen-Geiger Climate
Classification (1/2) Assessment
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U.S. Department of Interior
• Highest mean CWP (kg/m³) per climate
• Wheat - BSk (Arid-steppe-cold arid) = 1.33
• Corn - Dfa (Snow-fully humid-hot summer) = 2.53
• Rice - BSh (Arid-steppe-hot arid) = 0.87
• Highest mean CWP (kg/m³) per climate
• Wheat - BSk (Arid-steppe-cold arid) = 1.33
• Corn - Dfa (Snow-fully humid-hot summer) =
2.53
• Rice - BSh (Arid-steppe-hot arid) = 0.87
• Lowest mean CWP (kg/m³) per climate
• Csa (Warm temperate-summer dry-hot
summer) had the lowest mean CWP for all 3
crops
• Wheat = 0.82
• Corn = 1.06
• Rice = 0.51
• Climate Csa has
max potential
for increase in CWP
relative to other climate
classifications in this
study
Results Part 2.1: CWP Köppen-Geiger Climate
Classification (2/2) Assessment
U.S. Geological Survey
U.S. Department of Interior
Wheat. Rice.Corn.
• Mean CWP (kg/m³)
per 10° latitude zone
• Wheat
• 40o - 50o = 1.10
• 20o - 30o = 0.89
• Corn
• 40o - 50o = 2.45
• 30o - 40o = 1.67
• 20o - 30o = 0.94
• Rice
• 30o - 40o = 0.99
• 10o - 20o = 0.71
• 20o - 30o = 0.63
Results Part 2.2: CWP Latitude (1/2) Assessment
U.S. Geological Survey
U.S. Department of Interior
• Overwhelming evidence
of significant increase
in CWP with increase
in latitude across
wheat, corn, & rice
Results Part 2.2: CWP Latitude (2/2) Assessment
U.S. Geological Survey
U.S. Department of Interior
Wheat. Rice.Corn.
For FAO soil types:
• no mean CWP values
per soil type, were
statistically different at
or above 90%
confidence interval for
significant comparison
across all crop types
Results Part 2.3: CWP Soils Assessment
U.S. Geological Survey
U.S. Department of Interior
Wheat. Rice.Corn.
For:
• 1D: Latitude & Soil
• 1E: Latitude & Climate
• 1F: Climate & Soil
• Geospatial variable combinations 1D, 1E, & 1F
were not statistically different at or above 90%
confidence interval for significant comparison
across all crop types
Results Part 2.4: CWP Combined Variables
(Combinations of Köppen-Geiger Climate, latitude,
& soils) Assessment
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U.S. Department of Interior
U.S. Geological Survey
U.S. Department of Interior
Crop Water Productivity of Irrigated Croplands of the World, CWP (kg\m3)
Synthesis: CWP Maps
Wheat global CWP
categories (kg/m³):
• Low ≤ 0.75
• Medium >0.75
to <1.10
• High ≥1.10
CWP (Mean Values) by Country for Wheat: Mapped by Low, Medium, & High CWP
U.S. Geological Survey
U.S. Department of Interior
For Wheat
USA, China, Egypt, Turkey, Netherlands, Mexico, & Israel have high CWP
Corn global CWP
categories (kg/m³):
• Low ≤1.25
• Medium >1.25
to ≤1.75
• High >1.75
U.S. Geological Survey
U.S. Department of Interior
For Corn
USA, China, Romania, Argentina, & Hungary have high CWP
CWP (Mean Values) by Country for Corn: Mapped by Low, Medium, & High CWP
Rice global CWP
categories (kg/m³):
• L ow ≤0.70
• Medium >0.70
to ≤1.25
• High >1.25
U.S. Geological Survey
U.S. Department of Interior
For Rice
USA, China, & Philippines have high CWP. Australia & India have medium CWP
CWP (Mean Values) by Country for Rice: Mapped by Low, Medium, & High CWP
• USA & China have consistently high CWP
for wheat, corn, & rice
• Australia & India have medium CWP for
wheat and rice
• Egypt, Turkey, Netherlands, Mexico, &
Israel have high CWP for wheat
• Romania, Argentina, & Hungary have high
CWP for corn
• Philippines has high CWP for rice
• All other countries have either low or medium
CWP for all 3 crops
CWP (Mean Values) by Country for All Crops:
Global & Regional Summary of: Low, Medium, & High CWP
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U.S. Department of Interior
U.S. Geological Survey
U.S. Department of Interior
Crop Water Productivity of Irrigated Croplands of the World (kg\m3)
Synthesis: Water Savings
• As CWP increases, total quantum of water use decreases
Water use of Wheat Versus CWP
U.S. Geological Survey
U.S. Department of Interior
Wheat
• Highest
consumers of
water also have
most potential for
water savings.
• Countries with the
most water use
that can make
biggest water
savings impact
based on this
study include:
USA, India, & China
• Highest
consumers of
water also
have most
potential for
water savings.
• Countries with
the most water
use that can
make biggest
water savings
impact based
on this study
include:
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U.S. Department of Interior
Corn
Water use of Corn Versus CWP• As CWP increases, total quantum of water use decreases
USA, China, & Brazil
• Highest
consumers of
water also
have most
potential for
water savings.
• Countries with
the most water
use that can
make biggest
water savings
impact based
on this study
include:
U.S. Geological Survey
U.S. Department of Interior
Rice
Water use of Rice Versus CWP• As CWP increases, total quantum of water use decreases
India, China, & Pakistan
• Determined potential quantum of water that can be
saved from each crop, in each country by
increasing CWP by 10%, 20%, and 30%
• High potential for increasing CWP of wheat, corn,
& rice in most countries of the world
• Even just a 10% increase in CWP of wheat grown
in India can potentially save 6,974 billion L of water
• Can help alleviate intensive agricultural water
withdrawal and help restore the local water cycle.
• Equivalent to 6,974 lakes of 100 m³ in volume.
• Or equivalent to 273,490 Lincoln Memorial Reflecting
Pools (25,500 m³)
Global Water Savings of Wheat, Corn, & Rice:
Relative to CWP Improvement
U.S. Geological Survey
U.S. Department of Interior
Wheat growing regions in India.
Image: USDA Foreign Agricultural Service
Lincoln Memorial Reflecting Pool,
Washington, D.C.
Image: Wikimedia Commons
U.S. Geological Survey
U.S. Department of Interior
Crop Water Productivity of Irrigated Croplands of the World (kg\m3)
Conclusions
1. Meta-analysis of CWP of the 3 Irrigated Crops
▪ Established low, medium, high CWP of wheat, corn,
and rice based on meta-analysis using data from 111 peer-
reviewed publications;
2. CWP maps of the countries
▪ Produced CWP maps of the leading crop growing
countries of the world for 3 crops showing high, medium,
and low CWP;
3. Water savings
▪ Calculated and illustrated the quantum of water that
can be saved by improving CWP of each crop for all the
major crop producing countries of the world.
▪ As CWP increases total water use decreases
Concluding Thoughts:
U.S. Geological Survey
U.S. Department of Interior
U.S. Geological Survey
U.S. Department of Interior
Crop Water Productivity of Irrigated Croplands of the World (kg\m3)
Publication
CWP Publication: Foley et al., 2019
U.S. Geological Survey
U.S. Department of Interior
??? Add the
publication??
A meta-analysis of global crop
water productivity of three
leading world crops (wheat, corn,
and rice) in the irrigated areas
over three decades
International Journal of Digital Earth
Received March 15, 2019
Accepted July 25, 2019
Available at:
https://www.tandfonline.com/doi/full/
10.1080/17538947.2019.1651912
Thank you: Any Questions?
Acknowledgments: U.S. Geological Survey’s (USGS) Water SMART (Sustain and Manage America's Resources for Tomorrow)
project. We also gratefully acknowledge Northern Arizona University. The use of trade, product, or firm names is for descript ive
purposes only and does not constitute endorsement by the U.S. Government.
Contact: [email protected]