THE ART OF IRRIGATION. 



17 



thing seems all right to one who has never seen 

 anything better. But a man used to buying fruit on 

 the trees, like most of the buyers in California, would 

 not make an offer on it. You might think his notions 

 were high, yet, when we come to pick the crop about 

 one-third only, is fit for market, of which third not 

 over one-half is of first grade. Of the remaining 

 two-thirds the greater part is fit only for the cider 

 press, while the rest goes to the pig pen. Of course 

 a good many of the low grade apples are sent to 

 market along with the rest, but as they go only 

 toward helping pay the expenses, and often fail to do 

 that, they can be counted only as fit for cider. Nearly 

 all the profit is in the first grade, and the percentage 

 of this is very light. 



The failure of this tree to do full duty has prob- 

 ably several causes, but one of the main ones was a 

 lack of sufficient water to evaporate at the right 

 time. The orchard had not been plowed for an age, 

 and the hard ground shed too much of the short dash- 

 ing rains of summer, and did not absorb enough. Of 

 the amount that did enter the ground the thick sod 

 and weeds perspired away much that the tree should 

 have had. Just at the time, too, when the weather 

 was the hottest, the air the driest, and the days the 

 longest, the rain held off several days or weeks too 

 long, and this trick it may have played several times. 

 Consequently, though the ground may have been 

 moist enough to enable the roots to extract the chem- 

 icals from the soil, and enough to keep up the sap 

 and the water in the fruit, it could not give the tree 

 enough to perspire. Transpire is the scientific term, 

 but perspire is more correct. The tree may have 

 needed fertilizing, and undoubtedly the ground needed 

 aerating, but no amount of these would have taken 

 the place of plenty of water to keep all the pores of 

 the leaves going at the right times. If you figure 

 the leaf surface of a large tree you will find it very 

 great, and though it might do pretty well and look all 

 right the running out of the crop into a large per- 

 centage of low grade is inevitable unless the demands 

 of these pores are complied with. 



Nowhere is this so well shown as in the contrast 

 between a young tree and an old one. A young 

 tree perspires apparently as much in proportion 

 to its size as an old one. Its roots should also 

 cover as much proportionate space. Yet it is cer- 

 tain that a young tree may have nearly all of its 

 fruit large and perfect, while an old tree of the 

 same sort in full bearing, standing near it and 

 having exactly the same treatment and conditions, 

 may be loaded with fruit of which not a specimen is 

 eatable. Many a self-made sage has by the work of 

 a young tree been fooled into the belief that his land 

 did not need irrigation. The county of San Diego, 

 Cal., has been set back ten years by a lot of 

 antiques who could not heed the warning that others 



had been deceived in the same way. Though the 

 proof lay within a hundred miles of their noses, they 

 were too wise to go to see if any one else had ever 

 been fooled by the same discovery. 



The failure to keep up this supply of water for 

 perspiration at exactly the right times may mean so 

 many dollars an hour out, of one's pocket without his 

 suspecting it. It is the principal reason why the best 

 orchards of the Atlantic coast yield so little high-grade 

 fruit in comparison with the well-irrigated orchards 

 of the far West and is the reason why the East must 

 irrigate as well as the West and will do so in thousands 

 of places before this book is forgotten. The rain is 

 everywhere too treacherous to furnish at the proper 

 time the water the trees must have. It may average 

 up all right, but that is not enough. The control of 

 the water is what is needed and in this lies the great 

 advantage of irrigation over rain. Two weeks too 

 long of dry weather may shrink your purse enough to 

 pay for your entire irrigating plant if you have high- 

 grade crops. And this same principle applies with 

 more or less force to all crops. Some are of such low 

 value that it may not pay to water them, but in the 

 long run will do as well to let them take their chances 

 on the rainfall. No rules can be given for determin- 

 ing that, for it will depend on the cost of water and its 

 application in the particular case. 



Having fully realized the amount of water vegeta- 

 tion needs and why it needs it, and that it is one of 

 those things that, when needed at all, is needed very 

 much, the next step is to understand fully the evils of 

 too much water, or even a proper amount of water at 

 the wrong times. Farther on we shall see these more 

 in detail, but here we will glance at only two of them. 



First, for good results the ground needs aerating. 

 Any work on agricultural chemistry will tell you why 

 but you need not go to books for the proof of it. You 

 see it plainly in subsoil which is often just as rich as 

 top soil but will yield little until it has been turned 

 up for a year or two to the air and sun. The farmers 

 used to call it " sour." It contains all the elements of 

 fertility, but the air must penetrate it to get them into 

 available form for the plant to assimilate. 



The same is true of the top soil though the contrast 

 be less striking. The formation or nitrates and the 

 change of phosphates into forms that can be readily 

 assimilated by the roots, with other processes of pre- 

 paring plant food, are going on all the time, and the 

 presence of air in the soil is essential to them. And 

 this air must be constantly fresh or as nearly so as 

 possible. This is proven by the difference between 

 orchards in California irrigated in the old style with- 

 out cultivation and those where the watering is fol- 

 lowed by constant stirring of the soil. The difference 

 is far too great to be explained by the retention of 

 moisture by the mulch thus formed. The soil can be 

 kept wet enough in other ways but the more you do 



