Crops (Wheat, Corn, & Rice) in the Irrigated Areas: An ... · Crops (Wheat, Corn, & Rice) in the Irrigated Areas: An Assessment from Remote Sensing & Non-Remote Sensing Studies Over

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

U.S. Geological Survey

U.S. Department of Interior

Problem and the Need

Big Picture, Background



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



Background:



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






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:






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:




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



1A) Köppen-Geiger Climate Classification

1B) FAO Soil-Type

1C) Latitude 10° Zones

Methods Part 1: Spatial Mapping of CWP



Methods Part 2: Statistical Analysis of CWP



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)



▪ 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)






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



Results Part 1: CWP Köppen-Geiger Climate

Classification (1/2) Assessment



• 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



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



• Overwhelming evidence

of significant increase

in CWP with increase

in latitude across

wheat, corn, & rice

Results Part 2.2: CWP Latitude (2/2) Assessment



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



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





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



For Wheat

USA, China, Egypt, Turkey, Netherlands, Mexico, & Israel have high CWP

Corn global CWP


• Low ≤1.25

• Medium >1.25

to ≤1.75

• High >1.75



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


• L ow ≤0.70

• Medium >0.70

to ≤1.25

• High >1.25



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






Synthesis: Water Savings

• As CWP increases, total quantum of water use decreases

Water use of Wheat Versus CWP



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:



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:



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



Wheat growing regions in India.

Image: USDA Foreign Agricultural Service

Lincoln Memorial Reflecting Pool,

Washington, D.C.

Image: Wikimedia Commons




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:






Publication

CWP Publication: Foley et al., 2019



??? 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]

Documents

Crops (Wheat, Corn, & Rice) in the Irrigated Areas: An ... · Crops (Wheat, Corn, & Rice) in the Irrigated Areas: An Assessment from Remote Sensing & Non-Remote Sensing Studies Over