School of Agriculture, Food and Ecosystem Sciences - Theses

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End date: 1959 × Subject: Pastures ×

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    A partial analysis of border check irrigation
    Bartels, Leo Francis ( 1956)
    The Border Check method of irrigation, widely used in Australia and overseas for the irrigation of pasture crops, may be described as a method of applying water to land between parallel ridges or checkbanks. Under ideal conditions the land should have no cross slope between the banks, but there is usually a slope in the direction of irrigation. Water is admitted at the head of the strip or irrigation bay, and the flow is diverted when, in the operator's estimation, the ponded water will carry to the end of the strip without wastage. With experience it is possible to judge the cut-off point with considerable accuracy. Depending upon soil type and the natural slope of the ground, bays may be up to 1,200 feet long; and 70 feet wide, with average dimensions of 600 feet by 30 feet. It is the purpose of this thesis to examine some of the factors influencing the movement of water down a border strip, and the infiltration of this water into the soil. It is hoped that such studies will lead ultimately to a more critical assessment of border check layout in relation to soil type, topography, etc., and that it may be possible to determine accurately the dimensions needed for efficient use of irrigation water in a particular case. That efficient irrigation is necessary is brought out by the fact that one inch of excess water passing down to the water table may raise it by as much as one foot (49). The major factors influencing the movement of water down a border strip are as follows :- (1) The infiltration characteristics of the soil. (2) The flow per unit width of border strip. (>) The slope of the land in the direction of flow. (4) The resistance of the plant cover to water movement. Minor factors involved include the soil and water temperatures, the salt content of the irrigation water, the head of water during irrigation, the turbidity of the water, the nature of the soil colloids, etc. Most of these, however, influence irrigation by their effect on the infiltration at a particular point. In the work reported upon herein an attempt has been made to evaluate the influence upon pasture irrigation of the infiltration characteristics of the soil, and the density of pasture cover.
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