686 POPULAR SCIENCE MONTHLY. 



received at the surface all the water given them, while 2 and 4 were 

 subirrigated by means of a three-fourth-inch glass tube which extended 

 some three inches vertically into the soil. 



These plants started all alike, and in every other respect except 

 water-supply had an even chance, so that the difference in their develop- 

 ment, as seen two months after the seeds were sown, is highly in- 

 structive. The thing which at once strikes the eye is the hopeless con- 

 dition of the plants numbered 3, which, having had a meager supply of 

 water, applied wholly at surface, had been left behind in the race at an 

 early day and were now drying up. The plants numbered 4 had re- 

 ceived exactly the same amount of water, but it was placed, by the 

 simple method of subirrigation already described, where it would be 

 utilized with a minimum loss by evaporation. 



A comparison of numbers 1 and 2 indicates that there is no virtue 

 in subirrigation, in itself considered. It is merely a means of prevent- 

 ing waste. Both of these had received a large quantity of water, the 

 former at the surface, and the latter by way of subirrigation. As far 

 as this experiment goes, then, it appears that aside from alkaline or 

 other conditions requiring special treatment, which it is not the purpose 

 of this article to discuss, water may be applied indifferently at or below 

 the surface, if there is only enough of it. It is simply a matter of 

 supplying the roots of the plant with all the water it requires. But if 

 it only needs about half as much when applied in the simple way that 

 has been described, the fact is of sufficient importance to engage the 

 attention of horticulturists from Colorado to California. It is true 

 that reports on the results of subirrigation, thus far, have not been 

 encouraging in all respects, and the application of such methods on a 

 large scale would necessarily involve a rather large initial outlay; but 

 when one considers the great expense involved in preparing for the 

 irrigation of an orange grove, say, in southern California, and the con- 

 tinual outlay of time, labor and money required by the present wasteful 

 methods of applying water, it may well be asked whether some simple 

 method of subirrigation may not be developed which, when once the 

 practical difficulties have been overcome, will prove in the end more 

 economical as regards cash outlay, and at the same time make it possible 

 for the available water to do double duty. 



It is to be borne in mind that with very few apparent exceptions, 

 such, for example, as the areas bordering upon the lower Colorado, the 

 arid states and territories are nowhere possessed of an unlimited water- 

 supply ; in most cases there is a fixed limit, beyond which no amount of 

 ' development ' will produce more water. If, then, by economical 

 methods, a given quantity of water — all that can be depended upon for 

 a certain area — can be made to irrigate satisfactorily twice as many 

 acres as by wasteful methods, he who shows how this can best be done, 

 and inaugurates the doing of it, will deserve well of his country. 



