lo April, 1911.] 



Irrigation. 



regulators. These ditches will be spaced to suit particular cases, but 

 from 5 to 8 chains may be taken as a guide Arrows show the direc- 

 tion of flow of water. When regulating the water, provision should be 

 made for allowing surplus water (if any) from the furrows fed by the 

 head ditch at A to escape into the ditch at B, and similarly from B to 

 C and from C to the lucerne or whatever else may be there planted. In 

 the absence of lucerne, a waste ditch should be provided, but experience 

 will result in waste being reduced to a minimum. Accidents will happen, 

 especially during the night, when, even if one stays up all the time, 

 breaks in ditches are often not seen immediately. 



Once water is turned in for irrigating 

 there should be no stopping until the 

 field is finished. There are, unfor- 

 tunately, quite a few irrigators who 

 strain every nerve to avoid night water- 

 ing, when, as a matter of fact, water- 

 ing is more effectually done then than 

 by day. No excuse for such a practice 

 is permissible. The hardship ( ?) is not 

 very great in the case of an orchard 

 which will probably be irrigated four, 

 or at most, five times in a season, and 

 it saves waste and loss of time conse- 

 quent on having to run water again 

 over the previously wetted area. It is 

 good practice to somewhat reduce the 

 supply from the main channel during 

 the night, when flushes are likely to 

 occur without being immediately noticed. 

 The experience gained in watering an 

 orchard a few times will enable an irri- 

 gator to so regulate his supply that he 

 can turn in without any anxiety, or, at 

 the worst, lose but very little sleep. 

 Irrigating is an art, and practice alone 

 will acquire it. 



In farming districts, water is mostly 

 used to flood pastures, areas for plough- 

 ing, or summer crops. The preparation 

 for this in respect of head ditches, outlets, 

 &c., is similar to that described for 

 orchard work, and the practice is alike 

 except that there are no furrows. Assum- 

 ing the land to be satisfactorily graded, all tha remains to be done is to so 

 regulate the flow from the outlets that an even film of water may spread 

 over the surface. The duration of flow will be governed mainly by the 

 profile of the land, and the chnractt-r and condition of the soil. It should 

 be borne in mind that slow watering is essential on steep slopes, and fast 

 watering on sandy soils and flat surfaces ; great care should be taken 

 that water is not allowed to lodge in places for any length of time, free 

 outlet f)eing given to drainage channels. Where there are no drainage 

 channels it will drpcnd largely on the ski!) of the irrigator to avoid 

 creating swamps. While irrigating, keep the water flowing. Dead 

 water means dead plants, and nothing looks worse than an irrigated 

 paddock studded with bare ]):itrh<'^ or swamps, apart from w;iste of land 

 •which is the serious consideration. 



71. ORCHARD IRRIGATION. 

 SECONDARY HEAD DITCHES. 



