Show TWO METHODS OF IRRIGATION Underflow System Is Quite Different From Advantages Advantages Advantage of the Former By E E. J J. J 1 M. M A. A Professor ProCessor of Agriculture California Agricultural Experiment t Station Is the application of ot water under the surface by a system of conduits It has received so much thought and outlay and has returned so little satisfaction that it must be looked upon as a horticultural ignis and only a passing reference need be given to It Various available publications describe Its different phases It seems fair fall to to conclude that satisfactory growth Is secured with less water by sub IrrIgation than by surface d distribution but It Is done at atan atan atan an outlay which is unwarranted either by the cost of water or by the value of the crop Results of ot greenhouse experiments experiments experiments ex ex- ex- ex are more satisfactory than those from open air work Even if even distribution could be had from any arrangement of oC underground pipes which which seems doubtful In view of wide experience It still remains true that for shallow-rooting shallow plants plants plants-In In open soils the water Is applied at too low Iowa a level It also appears that the escape from the surface cultivation Is of doubtful advantage contrary to the claims of advocates of gatlon and that thorough surface stirring which Is an Indispensable accompaniment of surface surface sur sur- face irrigation is worth all It costs through the superior thrift which it induces It seems a fair fall conclusion from present knowledge that gation Is practically unattainable because because because be be- cause of cost Inequality of distribution distribution distribution tion etc and possibly would be undesirable undesirable undesirable unde unde- even if these prohibitions were removed Underflow irrigation is quite different differ ditter ent from though the former former for for- mer often goes in local parlance as natural Underflow Isa is isa isa a natural movement of water through the subsoil outward from streams or downward from areas toward toward to to- I ward the country drainage now flow irrigation consists in reinforcing this flow or In imitating it by bringing water to follow the same course of oC distribution It Is an available method first where the ground water Is naturally near the surface and Irrigation water is easily obtained in large quantities second where an open soil through which water spreads readily Is found resting upon an impervious hardpan or slightly pervious clay which prevents prevents prevents pre pre- vents loss of water by percolation In both of these conditions the method of Irrigation Is the same viz to open deep furrows at considerable distances apart and keep them filled with water for a considerable time so that it may soak away in large quantities The addition will In the first case raise the ground water so that it will rise by capillarity to the plant roots in the second case the irrigation Water water water wa wa- ter will spread through the free soil solI flowing along the surface of the hardpan hardpan hardpan hard- hard pan or clay and will thus become available to plant roots These methods methods methods meth meth- are most apt to be useful with deep rooting trees and vegetables but they are also used where the conditions are favorable for grains and garden crops |