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Influence of Fertilization and Altitude on Energy Budgets for Native Meadows 1
Author(s) -
Grable A. R.,
Hanks R. J.,
Willhite F. M.,
Haise H. R.
Publication year - 1966
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1966.00021962005800020037x
Subject(s) - lysimeter , evapotranspiration , altitude (triangle) , sensible heat , environmental science , growing season , forage , fertilizer , atmospheric sciences , precipitation , agronomy , flux (metallurgy) , hydrology (agriculture) , zoology , soil water , soil science , chemistry , ecology , geography , biology , meteorology , geology , mathematics , organic chemistry , geometry , geotechnical engineering
Experiments were conducted for 2 years near Gunnison, Colorado, to evaluate the influence of N fertilizer and altitude on energy budgets of native wet meadows. Measurements included evapotranspiration from lysimeters (E t ), evaporation from Weather Bureau pans (E), net radiation (R n ), total short‐wave radiation (R 2 ), soil heat flow (S), air and soil temperatures, wind velocity, precipitation, and forage yields. During two periods of 1963, R n , advected heat (A), and E t were slightly but not significantly altered at one location by application of N fertilizer. S was 2% or less of R n , and A to lysimeters ranged from 6 to 11% of E t when data from all plots were averaged. Studies during the entire growing season of 1964 at altitudes of 2240, 2350, 2670, and 3080 m indicated that R n , R s , and E cannot be used to accurately predict E t for high‐altitude wet meadows. Although changes in R n or R s were generally accompanied by changes in E or E t , the ratios of the values changed sharply during the season because of advected energy and crop harvest. During at least 1 or 2 weeks just before midseason harvest, S was negligible and sensible heat flux to the lysimeters (−A) was as much as 26% of E t ; after harvest, however, S was about 20% of Et and sensible heat flux from the lysimeters (+A) was as much as 97% of E t . E t , E, and A (to lysimeters) during comparable periods generally decreased as altitude increased. The greatest photosynthetic efficiency obtained was about 2% of R n ; usually it was much less.