I(i2 JOUII.NAJ- Ol' TllK Dlil'AjriMKNT OF AcrUICU LTUKE.— AuG., 1922. 



l)e so great in this case, there is no knowing Mhat untold daniage niay 

 he done to the farm lower down where, perhai)s, the water that drains 

 from the upper farm appears as seepage water — there to deposit on 

 evaporation the soluble materials leached out of the soil and to cause 

 waterlogging. E.vcesaive use of aJlahne irafei-s icJiere the sod is 

 iccll drahied : It is essential when using " hraTc '' water that suffi- 

 ciently large quantities he used to cause underdrainage, and one must 

 check surface evaporation ])y cidtivating. In this way a coucentia- 

 iion of soluble material in the soil will be prevented. It is to be noted 

 that the water used must never have sufficient soluble matter in it to 

 injure plant growth. The danger, of course, in this case is to tin; 

 farmer below on whose farm the salt-charged waters may appear. 

 When alkaline waters are iised in quantities not su^citmt to '-ause 

 drainaije, it stands to reason that the soluble materials not taken up 

 by the plant must accumulate in the soil and later on injure plant 

 growth. Excessive use of water in soil having a high vater- 

 table : If we apply large quantities of water to the soil and the free 

 water drains through the soil to the natural water-table, the table 

 must rise, unless there is a means whereby the rise is prevented, say 

 ^ome natural drainage channel. The rise of the ground-water may 

 result in the water reaching the root zone, especially of deep-rooted 

 plants, with the result that the plants are drowned. If the ground 

 water be brak, then accumulations of brak will result at the surface, 

 due to the evaporation of water that has risen to the surface capil- 

 larily from the ground water. Brak may also be the outcome of the 

 following: (a) Leaky furrou-s: The canals that lead from the reser- 

 voir always lie at some distance above the land to be irrigated. 

 Should these furrows be leaky, then the water seeping through the 

 soil and dissolving soluble material may strike an imper\ious layer, 

 say of clay, and flow along this layer to appear lower down at the 

 surface, there to evaporate and deposit salts, and so ruin valuable 

 irrigable land. (6) Leaky dams and reservoirs : The same thing 

 happens when the dams are not water-tight. I have seen a salt-mine 

 below a storage reservoir! The salt was deposited where the percolat- 

 ing waters appeared at the surface below the dam after passing 

 through salt-charged shales. This land was once used for the produc- 

 tion of crops. It is to-day, as stated above, a salt-mine ! The farmer 

 who owns low-lying land in an irrigable valhy must always run the 

 risk of having his land rendered useless by neighboui's who use exces- 

 sive quantities of water higher up in the valley. Here again I can 

 say that I have seen thousands of acres of low-lying rich valley land 

 ruined because the farmers immediately under the irrigation canals, 

 higher up, used water to such an extent that their drainage water 

 appeared on the farms below, which became brak and waterlogged. 1 

 am not going to make recommendations regarding the reclaiming of 

 alkaline lands, for that is beyond the scope of this paper, and besides 

 I consider that prevention is better than cure. If all farmers will use 

 their water sparingly, and will see to it that their lands are well 

 drained naturally or artificially, I feel sure that most of our irrigation 

 problems will disappear. We have seen how the misuse of water by 

 one fai-mer may be tlie ruin of his neighbour. 



It is essential, therefore, for irrigation farmers to work togetlit'r. 

 I have seen ht, therefore, to close this article with the f ollo\\ ing 

 (|Uotati(iii : " The nature of irrigation is such as to bving itjto cjose 



