Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-28T02:22:21.743Z Has data issue: false hasContentIssue false

Leaf Area and Competition for Light between Plant Species using Direct Sunlight Transmission

Published online by Cambridge University Press:  12 June 2017

Graham K. Walker
Affiliation:
Dep. Land Resource Sci., former Grad. student
Robert E. Blackshaw
Affiliation:
Crop Sci. Dep., Univ. Guelph, Guelph, Ont. N1G 2W1
Jack Dekker
Affiliation:
Res. Stn., Lethbridge, Alta. T1J 4B1 Agron. Dep., Iowa State Univ., Ames, IA 50011

Abstract

A technique based on the relationship between leaf area index (LAI) and the transmittance of direct sunlight was developed for the in situ study of competition for light between plant species. Field studies were conducted in 1984 and 1985 using monocultures and mixtures of rapeseed (Brassica napus L.), wild mustard (Sinapis arvensis L. # SINAR), and common lambsquarters (Chenopodium album L. # CHEAL). LAI estimated nondestructively by this method agreed closely with LAI determined by conventional destructive techniques. Light measurements at several heights in the canopy were used to determine the vertical distribution of canopy leaf area. Combining this information with species heights allowed the separation of the canopy LAI into individual species LAI, from which light competition could be estimated by calculating the sunlit LAI of each species. The technique permits many detailed measurements in the same canopy throughout the growing season. The light sensor required is not costly and is simple to operate and to maintain.

Type
Research
Copyright
Copyright © 1988 by the Weed Science Society of America 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Literature Cited

1. Coble, H. D., Williams, F. M., and Ritter, R. L. 1981. Common ragweed (Ambrosia artemisiifolia) interference in soybeans (Glycine max). Weed Sci. 29:339342.CrossRefGoogle Scholar
2. Lang, A. R. G. 1986. Leaf area and average leaf angle from transmission of direct sunlight. Aust. J. Bot. 34:349355.Google Scholar
3. Lang, A. R. G., and Yueqin, X. 1986. Estimation of leaf area index from transmission of direct sunlight in discontinuous canopies. Agric. Forest Meteorol. 37:229243.Google Scholar
4. Lang, A. R. G., Yueqin, X., and Norman, J. M. 1985. Crop structure and the penetration of direct sunlight. Agric. Forest Meteorol. 35:83101.Google Scholar
5. Norman, J. M., Perry, S. G., Fraser, A. B., and Mach, W. 1979. Remote sensing of canopy structure. Proc. 14th Conf. Agric. Forest Meteorol., Minneapolis, MN, p. 184185.Google Scholar
6. Stern, W. R., and Donald, C. M. 1962. Light relationships in grass-clover swards. Aust. J. Agric. Sci. 13:599614.Google Scholar
7. Walker, G. K., and Blackshaw, R. E. 1985. Nondestructive estimation of leaf area index and light competition in mixtures. Proc. 20th Conf. Agric. Forest Meteorol., Phoenix, AZ, p. 94.Google Scholar
8. Warren Wilson, J. 1959. Analysis of spatial distribution of foliage by two-dimensional point quadrats. New Phytol. 58:92101.Google Scholar
9. Warren Wilson, J. 1967. Stand structure and light penetration. III. Sunlit foliage area. J. Appl. Ecol. 4:159165.Google Scholar