HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Marani, A. Articles by Ephrath, J. Search for Related Content PubMed Articles by Marani, A. Articles by Ephrath, J. Agricola Articles by Marani, A. Articles by Ephrath, J.

Penetration of Radiation into Cotton Crop Canopies¹

The penetration of radiation into cotton (Gossypium hirsutum L., ‘Acala SJ-2’) canopies was investigated in two field experiments in Negba (1980, irrigated by sprinklers), and in Nahal-Oz (1981, three irrigation treatments by a drip system). Photosynthetically active radiation (PAR) below the canopy was measured by a sensor moving on a 2 at track across the rows and integrated for periods of 30 min. The PAR was also measured above the canopy, and the percent of penetration was calculated. Plant height and leaf area index (LAI) were measured together with the radiation measurements. A high correlation was found between plant height and LAI, and both were highly correlated with radiation penetration. Plant height was found to be more useful than LAI as a predictor of radiation penetration, because its measurement in the field is more convenient. During periods of moisture stress, radiation penetration was usually lower than predicted by plant height. An examination of our data by using a model revealed that plant width was an important factor determining radiation penetration. The model accurately predicted radiation penetration into the canopy, provided that reliable estimates of essential plant parameters (e.g., plant height and width, LAI, and leaf angle distribution) had been input. Increased growth in height was usually associated with high rates of irrigation, whereas plant width was not. Plant width increased abruptly as soon as the first bolls began to develop, and this was followed by a rapid decrease in radiation penetration.

Key Words: Gossypium hirsutum L. • Irrigation • Leaf area index • Modeling • Moisture stress • PAR • Plant height • Plant width

² Associate professor and graduate research assistant.

Received for publication October 20, 1983.

This article has been cited by other articles:

				C. J. Fernandez and T. N. Trolinger Development of a Web-Based Decision Support System For Crop Managers: Structural Considerations and Implementation Case Agron. J., April 4, 2007; 99(3): 730 - 737. [Abstract] [Full Text] [PDF]