| Autor: |
P.J. Gregory, P.D. Ah Koon, J.P. Bell |
| Rok vydání: |
1990 |
| Předmět: |
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| Zdroj: |
Agricultural Water Management. 17:267-282 |
| ISSN: |
0378-3774 |
| DOI: |
10.1016/0378-3774(90)90074-9 |
| Popis: |
This study investigated the effects of 3 emission rates (1, 2 and 4 1 h −1 ) from drip irrigators on the distribution and drainage of water beneath a crop of sugar cane and a fallow plot. Soil hydraulic potential was measured intensively and regularly by a three-dimensional array of tensiometers. A computer program allowed linear interpolation of hydraulic potential between points of measurement and plotted the equipotential zones. Hydraulic conductivity characteristics (K ψ) were measured in the bare plot and the saturated conductivity at 77.5 cm depth (1.74 × 10 −7 m s −1 ) used to estimate drainage below both cropped and fallow plots. The fastest rate of emission (4 1 h −1 ) resulted in greatest lateral spread of water but emission rate did not affect the amount of drainage. More drainage occurred beneath the dripline than farthest from it and contrary to expectation the maximum loss by drainage was found to be beneath the point half way between emitters; this was interpreted as due to the overlapping pattern of water from adjacent emitters. Although drainage occurred beneath the entire bare plot, a small amount of upward flux (⪡1 mm d −1 ) was observed between the cane rows. Drainage from the bare plot (8.2 mm d −1 ) was greater than from the cane plot (0.9 mm d −1 ). The practical applications of the findings are discussed; the adoption of an emission rate of 4 1 h −1 and a wider spacing between emitters (currently 75 cm) by growers might allow the irrigation of a greater area of cane in these soils without increased drainage. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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