Some features of the ASCE Shopping cart and login features of the website will be down for maintenance on Sunday, June 16th, 2024, beginning at 12:00 A.M. ET and ending at 6:00 A.M. ET. During this time if you need immediate assistance at 1-800-548-2723 or [email protected].

Chapter
Apr 26, 2012

Performance of Crop Coefficients Inferred from NDVI Observations for Estimating Evapotranspiration and Irrigation Scheduling of Wheat

Publication: World Environmental and Water Resource Congress 2006: Examining the Confluence of Environmental and Water Concerns

Abstract

Time-based crop coefficients are often used to estimate daily crop evapotranspiration (ETc) for determining irrigation scheduling. Incorporating remote sensing observations to infer crop coefficients during the season could provide the spatial and temporal estimation of ETc that is needed for precise irrigation scheduling. Experiments conducted for two seasons with wheat investigated the use of reflectance-based and time-based basal crop coefficients (Kcb), integrated within the FAO-56 dual crop coefficient framework to compute the daily ETc for determining irrigation scheduling. The experiments consisted of two main treatments denoted as the normalized difference vegetation index (NDVI) and the FAO treatments. Six, replicated sub-treatments, equally embedded within the two main treatments, included three plant densities (typical, dense, and sparse) and two nitrogen levels (high and low). NDVI data obtained from frequent ground-based canopy reflectance measurements were used to calculate the Kcb for each NDVI plot via a previously defined relationship mat describes Kcb as a function of scaled NDVI. A single time-based Kcb curve, developed locally for standard crop conditions, was used to estimate the daily Kcb for the FAO treatment plots. Predicted Kcb compared favorably with derived Kcb determined from field measurements for both the NDVI and FAO methods for standard conditions (typical density and high N) during the first season. However, the time-based FAO Kcb curve failed to adequately describe derived Kcb for any sub-treatment condition during the second season when crop development was atypical due to a late crop emergence date, delayed nitrogen applications, and a shorter growing season. Because the NDVI Kcb closely tracked derived Kcb for all sub-treatments, ETc prediction for NDVI was superior to FAO, particularly during the second season. In either season, the differences between the NDVI and FAO treatments for grain yield and water use efficiency (yield/ETc) were not statistically significant. However, compared to the standard FAO Kcb curve, the NDVI-Kcb method resulted in a significant decrease in the irrigation water used.

Get full access to this chapter

View all available purchase options and get full access to this chapter.

Information & Authors

Information

Published In

Go to World Environmental and Water Resource Congress 2006
World Environmental and Water Resource Congress 2006: Examining the Confluence of Environmental and Water Concerns
Pages: 1 - 13

History

Published online: Apr 26, 2012

Permissions

Request permissions for this article.

ASCE Technical Topics:

Authors

Affiliations

D. J. Hunsaker [email protected]
USDA-ARS, United States Water Conservation Laboratory, 4331 E. Broadway Rd., Phoenix, AZ 85040. E-mail: [email protected]
P. J. Pinter, Jr.
USDA-ARS, United States Water Conservation Laboratory, 4331 E. Broadway Rd., Phoenix, AZ 85040
T. R. Clarke
USDA-ARS, United States Water Conservation Laboratory, 4331 E. Broadway Rd., Phoenix, AZ 85040
G. J. Fitzgerald
USDA-ARS, United States Water Conservation Laboratory, 4331 E. Broadway Rd., Phoenix, AZ 85040
A. N. French
USDA-ARS, United States Water Conservation Laboratory, 4331 E. Broadway Rd., Phoenix, AZ 85040

Metrics & Citations

Metrics

Citations

Download citation

If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.

View Options

Get Access

Access content

Please select your options to get access

Log in/Register Log in via your institution (Shibboleth)
ASCE Members: Please log in to see member pricing

Purchase

Save for later Information on ASCE Library Cards
ASCE Library Cards let you download journal articles, proceedings papers, and available book chapters across the entire ASCE Library platform. ASCE Library Cards remain active for 24 months or until all downloads are used. Note: This content will be debited as one download at time of checkout.

Terms of Use: ASCE Library Cards are for individual, personal use only. Reselling, republishing, or forwarding the materials to libraries or reading rooms is prohibited.
ASCE Library Card (5 downloads)
$105.00
Add to cart
ASCE Library Card (20 downloads)
$280.00
Add to cart
Buy Single Paper
$35.00
Add to cart

Get Access

Access content

Please select your options to get access

Log in/Register Log in via your institution (Shibboleth)
ASCE Members: Please log in to see member pricing

Purchase

Save for later Information on ASCE Library Cards
ASCE Library Cards let you download journal articles, proceedings papers, and available book chapters across the entire ASCE Library platform. ASCE Library Cards remain active for 24 months or until all downloads are used. Note: This content will be debited as one download at time of checkout.

Terms of Use: ASCE Library Cards are for individual, personal use only. Reselling, republishing, or forwarding the materials to libraries or reading rooms is prohibited.
ASCE Library Card (5 downloads)
$105.00
Add to cart
ASCE Library Card (20 downloads)
$280.00
Add to cart
Buy Single Paper
$35.00
Add to cart

Media

Figures

Other

Tables

Share

Share

Copy the content Link

Share with email

Email a colleague

Share