Leaf Area Dynamics of a Shortgrass Prairie in Colorado
1973
Knight, Dennis H.
Leaf area changes were studied at the Prawnee Grassland in northern Colorado. Specific objectives were (1) to measure seasonal changes in leaf area during 1970 and 1971, (2) to estimate the influence of irrigation, irrigation plus nitrogen fertilization, and grazing on leaf area, and (3) to calculate average daily above—ground productivity per unit of leaf area during the peak of the growing season. The point—quadrat method was used for leaf area measurement. Peak leaf area was reached in mid—June of both years, with a maximum Leaf Area Index of 0.55 in 1970. Both years were drier than average, but seasonal distribution of rainfall was different with a corresponding seasonal difference in LAI. Irrigation alone increased LAI about two—thirds, and irrigation plus fertilization increased LAI approximately tenfold. Different grazing treatments had little effect on total leaf area values. Above—ground productivity per unit leaf area averaged about 5 g/day/l² of leaf area in May and about 4 g in June and July 1970.
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