250 TWO METHODS OF FARM IRRIGATION. 



of making- these mistakes farmers make money ; but they make 

 less than they ought to for the amount of time, labour and water. 

 They are not getting- full value for their money. 



Remember that the man who raises the greatest percentage of 

 high-grade fruit or grain makes the greatest profit, and if there is- 

 a constant fluctuation in the vigour and growth of a tree or plant, 

 you cannot expect a high-grade yield. If the water has been 

 allowed to sink well into the ground so as to moisten the sub-soil, 

 you will find that in many instances one irrigation a month will be 

 sufficient for a large number of crops. As a rule you want a few 

 heavy irrigations followed by thorough cultivation ; if this is done 

 conscientiously you will be surprised at the results. Something 

 like 80 per cent, of the enormous fruit and grape crop in California' 

 is matured without any water after the fruit is set. This is simply 

 because there is enough moisture in the sub-soil. If lucerne wilts 

 on a dry sub-soil when it is between six or eight inches high, and 

 before it comes into full bloom, probably one-third of that cutting 

 is lost, perhaps even a half, no matter how quickly water is run 

 over the top. But if the sub-soil is made moist enough you can 

 often get a whole cutting with one single watering. I have known' 

 this done by some men in South Africa. As soon as a crop was 

 taken off, the ground was heavily watered, the surface was well 

 cultivated, and no more water was given until the new crop was 

 off. A farmer near Bethal, who built an irrigation dam a couple of 

 vears ago, was advised by me that three irrigations would be 

 enough for a winter crop. He wrote me less than two months 

 ago saying that he could irrigate more land than I told him, and" 

 said " from an experiment made I find that if I irrigate ground, 

 say in June or July, or even as early as the middle of May, and 

 the ground is immediately ploughed, harrowed and sown, the 

 moisture is retained, and no further irrigation required until the 

 middle of September, by which time, with average luck, rain 

 should do the rest for us." 



On this point, as with many others connected with irrigation, 

 there is no golden rule. You must study your sub-soil, and for 

 this purpose I know nothing better than an earth augur. If you 

 have a sub-soil of gravel, shingle, or boulders, your efforts to 

 moisten it may be about as profitable as pouring water into a sieve, 

 and if the sub-soil is pot-clay without facilities for drainage you 

 mav find your lands become waterlogged or sour. 



You must not imagine that a damp sub-soil is all that is re- 

 quired for every crop. Strawberries and shallow-rooted plants 

 require frequent waterings, because their roots never reach the 

 moisture in the sub-soil. \'arying conditions of soil, climate and 

 crops modify the methods of irrigation. As a rule, deep-rooted 

 plants require heavy waterings at long intervals of time, while 

 shallow-rooted plants require light waterings at short intervals of 

 time. That is the guiding principle : you must adapt the applica- 

 tion to your requirements. If your soil is shallow, it will not 

 require such heavy irrigations as deep soil ; but on the other hand, 

 if your soil is very deep, it may be a waste of water to wet it right 

 down to the bottom. 



