136 AUSTRALIAN AGRICULTURE. 



So that all plants must have water in some proportion ; 

 most of them in large proportion. They perish unless it is 

 supplied. 



" Irrigation ?" In the agricultural sense, this term 

 applies to watering by artificial means. It has, ever since 

 the time of white settlement, been a subject of interest in 

 Australia, and irrigation has been carried out sufficiently 

 for pastoral, general farming, and gardening purposes, to 

 supply sufficient data to work on. Then Southern Europe, 

 California, Utah, Colorado, Mexico, India, Syria, Egypt, 

 even the South Sea Islands afford further details of use 

 to the progressive agriculturist. From the time of the 

 Romans onwards, works have been constructed for water 

 storage for irrigation purposes a very different arrange- 

 ment from water storage for cities, both as to cost, and the 

 quality of the water. 



Methods of Irrigation. They are very various. 

 From the earliest times, water has been applied to plants 

 when the rainfall was not sufficient for the purposes of the 

 agriculturist. The defined methods of applying water 

 are by sprinkling all over the plants ; by saturating or 

 soaking the soil without sprinkling, and by a combination 

 of both processes. The basin system is suitable for sandy 

 and gravelly soils, and is followed extensively in California. 



Advantages and Disadvantages. Sprinkling seems 

 the more natural method. It is most like rain. The 

 disadvantages of sprinkling are that sediment and mineral 

 substances in the water dry upon or crystalize on growing 

 plants, and may destroy them by closing the breathing 

 pores. When water is used on the soil only, this risk is 

 avoided, and water may be used in that way with excellent 

 effect, which would be destructive if used the other way. 

 There is also an immense difference in the cost of the 

 methods of applying water. 



Irrigation and Drainage. The chapters no drain- 

 ing and cultivation explain how necessary and beneficial it 

 is to have rain water sink into the soil to the full depth 

 to which the roots penetrate. The same rule applies in 

 irrigation. The water, put it on in which way we may, 

 must sink into the soil, and do its work through the 



