Microenvironment of a dynamic annual community in relation to range improvement
AuthorsR. A. Evans
B. L. Kay
J. A. Young
Authors AffiliationsRaymond A. Evans was Range Scientist, Agricultural Research Service, U. S. Department of Agriculture, Renewable Resources Center, University of Nevada, Reno, Nevada; Burgess L. Kay was Specialist, Department of Agronomy and Range Science, University of California, Davis, California; James A. Young was Range Scientist, Agricultural Research Service, U. S. Department of Agriculture, Renewable Resources Center, University of Nevada, Reno, Nevada.
Hilgardia 43(3):79-102. DOI:10.3733/hilg.v43n03p079. March 1975.
Syntheses of microenvironments based on monitoring are needed for understanding complex phenomena of an ecosystem and for establishing benchmark or standard regimes of temperature, light, and soil moisture for laboratory experiments involving seed germination, seedling growth, and other plant responses. These studies, in turn, answer questions about the dynamics of a plant community.
The microenvironment was monitored and vegetation was intensively sampled to interpret complex responses of an annual rangeland community to chemical weed control and reseeding.
Yield and density of plants varied among years, with aspect, within seasons, and in response to paraquat (1,1?-dimethyl-4,4?-bipyridinium ion). Establishment of hardinggrass and perlagrass (Phalaris spp.) was related directly to paraquat treatment and reduction of competition from resident annuals. Species and aspect (north and south slope) differences were more important in establishment of annual clovers (Trifolium spp.), with reduction of competition not the overriding factor.
Available soil moisture permitted seed germination, seedling emergence, and growth of plants in this community. Temperature controlled the general rate of growth, and also created detectable differences in plant response when it dropped low enough to affect germination of seeds or caryopses or rose high enough to stress plants directly, or indirectly by more rapid depletion of soil moisture. The overriding factor of competition which prevented establishment of hardinggrass and perlagrass was interception of light by the canopy of annual plants during the growing season. The shading effect was most severe at ground level. During crucial periods of emergence and growth of the seeded species, this shading was virtually restricted to 1 or 2 cm above the surface. Soil-moisture depletion mattered primarily at the end of the growing season, but in some restricted periods during the season it became an important factor.
Biswell H. H. Ecology of California grasslands. J. Range Manage. 1956. 9:19-24. DOI: 10.2307/3894645 [CrossRef]
Biswell H. H., Graham C. A. Plant counts and seed production on California annual-type ranges. J. Range Manage. 1956. 9:116-18. DOI: 10.2307/3894229 [CrossRef]
Evans R. A., Holbo H. R., Eckert R. E. Jr., Young J. A. Functional environment of downy brome communities in relation to weed control and revegetation. Weed Sci. 1970. 18:154-62.
Evans R. A., Young J. A. Plant litter and establishment of alien annual species in rangeland communities. Weed Sci. 1970. 18:697-703.
Youngner V. P., McKell C. M. Competition within the grass community. Grass Biology and Utilization. 1972. New York, N.Y.: Academic Press. 426p.
Evans R. A., Young J. A., Kay B. L. Germination of winter annual species from a rangeland community treated with paraquat. Weed Sci. 1973. 22:185-87.
Heady H. F. Vegetational changes in the California annual type. Ecology. 1958. 39:402-16. DOI: 10.2307/1931750 [CrossRef]
Hsieh J. H. C., Hungate F. P. Temperature compensated peltier Psychrometers for measuring plant and soil water potentials. Soil Sci. 1969. 110:253-57. DOI: 10.1097/00010694-197010000-00005 [CrossRef]
Hughes A. P., Bainbridge R., Evans G. C., Rackham O. The importance of light compared with other factors affecting plant growth. Light as an Ecological Factor. 1966. New York, N.Y.: John Wiley and Sons. 452p.
Kay B. L., Owen R. E. Paraquat for range seeding in cismontane California. Weed Sci. 1970. 18:238-43.
Love R. M. Range improvement experiments at the Arthur Brown Ranch, California. J. Range Manage. 1952. 53:120-23. DOI: 10.2307/3894470 [CrossRef]
Robbins W. W. Alien plants growing without cultivation in California. Calif. Agr. Exp. Sta. Bul. 1940. 637:1-128. https://archive.org/details/alienplantsgrowi637robb
Young J. A., Evans R. A., Kay B. L. Germination characteristics of range legumes. J. Range Manage. 1970. 23:98-103. DOI: 10.2307/3896108 [CrossRef]
Young J. A., Evans R. A., Kay B. L. Germination of caryopses of annual grasses in simulated litter. Agron. J. 1971. 63:551-55. DOI: 10.2134/agronj1971.00021962006300040011x [CrossRef]
Young J. A., Evans R. A., Kay B. L. Temperature requirements for seed germination in an annual-type rangeland community. Agron. J. 1973. 65:656-59. DOI: 10.2134/agronj1973.00021962006500040038x [CrossRef]
Young J. A., Evans R. A. Conversion of medusahead to downy brome communities with diuron. J. Range Manage. 1972. 25:40-43. DOI: 10.2307/3896662 [CrossRef]
Also in this issue:Cooperative Extension: A tradition of investing in California's future
Cooperative Extension at 75 People investing in California's future
4-H takes on new challenges
EFNEP makes a difference
New era for agricultural research in the San Joaquin Valley
Simple monitoring of black vine weevil in vineyards
Calcium amendments for water penetration in flooding systems
Agricultural sustainability: An overview and research assessment
Plants that remove selenium from soils
Effect of fungicides on shot hole disease of almonds
Foraging in Central Valley agricultural drainage areas
Control of potassium deficiency syndrome in cotton by soil solarization
Pistachio culls acceptable in livestock feed
Seasonal changes may cause vitamin A deficiency in range heifers
Effect of harvesting and handling on damage in canned kidney beans
SAW employment data and the need for RAWs
Exotic fruit fly pests and California agriculture