358 Journal of Agriculture, Victoria. [10 June, 1918. 



Plate 165 illustrates a main articulation channel at Shepparton 

 settlement, which was brought under irrigation about ten years ago. 



Plate 166 shows a main channel entering an orchard settlement area 

 with the fruit trees situated to the right. 



In localities where porous soils exist seepage from the channels is 

 prevalent, but to prevent this, and protect land-owners in these places, 

 the channels are constructed or lined with cement concrete. 



The chief factors essential to successful irrigation, once the water 

 is made available, consist of a perfectly graded orchard surface of 

 deep, rich, friable soil, a permeable subsoil to afford good drainage, and 

 the smaller supply channels conveniently arranged. 



The virgin surfaces of the Goulburn Valley irrigation areas were 

 almost invariably of naturally perfect grade, and where rare inequalities 

 did occur these were of only minor importance and easily rectified. In 

 other districts, however, owing to more serious surface inequalities con- 

 siderable difficulties are experienced and expense involved in regulating 

 the grade to irrigation requirements. 



When all the preliminary arrangements have been completed and 

 the water is made available for the orchard its application to the trees 

 requires careful and intelligent management. Some years ago a practice 

 often employed by irrigationists in the north was to flood the whole 

 orchard area with water, when available, to a depth of from 4 to 6 

 inches, frequently irrespective of the condition of the soil or the indivi- 

 dual requirements of the trees. Orchardists, who carelessly carry out 

 this phase of their work, especially in situations where highly satisfac- 

 tory results are difficult to obtain, set up soil conditions, even more 

 inimical to the welfare of their trees than those previously existing. 

 The experience of the writer, while inspector in charge of the Goulburn 

 Valley irrigation settlements, as well as that gained by the settlers 

 themselves, is that the furrow method of applying the water- is the most 

 economical and generally satisfactory system. By this means the 

 operator is enabled to control the supply and apply the water in quan- 

 tities to suit the different classes of soils in their then existing condi- 

 tion, and meet the requirements of the kinds and varieties of trees under 

 treatment. 



In connexion with the flooding method it may be further stated that 

 a considerable quantity of water is lost through evaporation during 

 warm weather. The flood, on the surface is often visible for a consider- 

 able time, and its presence there almost prevents the escape from the 

 soil's interspaces of the air, which impedes the downward percolation 

 of the water. Cultivation contingent on irrigation becomes much more 

 necessary in the case of soil drying up after flooding than when the 

 furrow system is employed, because a considerably greater number of 

 capillary vapour ducts is created in a given area treated under the 

 former system than appears after the latter. 



After flooding, particularly if the water be used sparingly on a 

 surface with impervious sub-strata, which prevents rapid downward 

 penetration, the undesirable condition of shallow rooting is encouraged. 

 Whereas, when furrows are employed these may be ploughed to a suit- 

 able depth and the water controlled in them until such time as the 

 subsoil is saturated, and more favorable conditions for lower root 

 establishment thus created than would follow the flooding method. 



