ISSN: 0041-3216

ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 55 Number 1
Research Papers
Comparison of measured and calculated consumptive use of water by savanna grass, Axonopus compressus (Swartz) Beauv.
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The monthly consumptive use of water by savanna grass during the dry season in Trinidad (January to May) was calculated by the BLANEY and CRIDDLE formula using crop growth stage coefficients measured for pasture grasses in the U.S.A. and 42 year (1932-73) climatological data measured in Trinidad. The differences between calculated mean monthly consumptive use and mean monthly consumptive use measured with lysimeters in Trinidad for 13 years (1955-67) were 6, 1, 3, 3 and 10 per cent for the months of January, February, March, April and May, respectively. The irrigation requirement of this grass was calculated as the difference between consumptive use and effective rainfall and was about 40 cm for the months of January to May. The method of calculating effective rainfall from total rainfall is also outlined.