THE IRRIGATION AGE. 



83 



THE PRIMER OF IRRIGATION. 



COPYRIGHTED, 1903, BY D. H. ANDERSON. 



(soth Chapter Concluded.) 



Tobacco requires a soil very carefully prepared. 

 The plants are raised from seed in frames and set out 

 the same as cabbage and tomatoes, carefully puddled 

 in and the rows irrigated by a small stream until the 

 plants take root, which they will do in a few days. 

 Frequent and thorough cultivation of the soil is neces- 

 sary, but water must be applied sparingly, one irriga- 

 tion during the middle period of growth bein'g suffi- 

 cient, provided the cultivation is thorough and the 

 subsoil moist. When the soil is dry and warm, irri- 

 gation may be applied every ten days after the first 

 month of growth. In the arid region top or leaf spray- 

 ing is necessary, but tobacco is not recommended as a 

 .plant profitable in arid soil, it thriving best in a warm, 

 moist climate. 



STATISTICS OF PBODUCTION. 



It may be of interest to know the amount of the 

 foregoing profitable plants .produced in the United 

 States. The following is an approximate of quantities 

 as nearly as can be ascertained from the means of in- 

 formation : 



Wheat 753,460,218 bushels 



Barley 178,795,890 bushels 



Oats 736,808,724 bushels 



Rye 30,344,830 bushels 



orn 2,522,519,891 bushels 



Eice 283,665,627 pounds 



Cotton 1,384,000,000 pounds 



Tobacco 500,000,000 pounds 



Hops 20,000,000 pounds (about) 



Flaxseed 5,000,000 bushels (about) 



The total value of which was in the neighborhood 

 of two thousand million dollars ($2.000,000,000). 



CHAPTER XXI. 



IRRIGATION OF PROFITABLE PLANTS. 



(Continued*) 



It has been impressed upon the mind of the 

 reader in the preceding chapters that plants draw 

 their food from moisture and not from water. 

 True, moisture comes from water, but the mean- 

 ing sought to be conveyed is that moisture is a 

 food solution, a preparation for nourishing the plant 

 its "pap," so to speak. When water is applied to the 

 soil it attacks the various soluble salts, both organic 

 and inorganic, and causes a chemical change to take 

 place, or, rather, a series of chemical changes, and 

 in that way the elements in the soil are converted into 

 food. There are fermentations, transformations and 

 many radical changes effected, until the water con- 

 verted into moisture can not be recognized as water 

 at all or any more than vinegar, wine or potatoes can 

 he called water, although they contain water as an 

 element in their composition, as an ingredient. 



This fact can not be overestimated, because on its 

 understanding hinges the art of irrigation. There 

 are air plants which have no rooting in the soil, yet 

 they could not live without moisture. There are also 

 plants which flourish in the desert, where the soil is 

 ntirely dry for a hundred feet below the surface, yet 



these could not live without moisture. The question 

 is, Where do they get it? They certainly do not re- 

 quire water, for there is none within reach of their 

 roots or leaves. They obtain it from the atmosphere, 

 and this atmosphere is an -element that must be reck- 

 oned with by every irrigator. We know that there is 

 always a certain quantity of moisture in the atmos- 

 phere, which is better knpwn by the name of "hu- 

 midity," and this humidity can be easily measured. 



When the atmosphere is charged with 80 to 100 

 per cent of moisture, or humidity, that moisture is 

 precipitated upon the soil in the form of rain, snow, 

 etc. From 50 per. cent to 80, when the air is cool, 

 we have dew, fog, etc., visible to the eye. When the 

 air is warm, however, the moisture is not perceptible 

 to the eye, but it is there nevertheless. 



Now, with the atmosphere weighing or pressing 

 upon the earth's surface about fifteen pounds to every 

 square inch, there is not a nook, cranny or opening that 

 it does not penetrate, and it carries with it the moisture 

 it contains, and when it comes in contact with any ab- 

 sorbent, as the soil undoubtedly is, it leaves its moist- 

 ure there. It is for this reason that it is insisted upon 

 so strenuously that the farmer must keep his soil open 

 to 'the air the soil should be aerated as much as pos- 

 sible. This done carefully and constantly, the labor 

 of irrigation is rendered easier, and its effects more 

 perceptible; likewise less application of water will 

 prove adequate to the raising of any plant. 



The necessity for this aeration of the soil is the 

 same in the cereals alluded to in the last chapter as 

 in the root plants and tubers. In the case of cereals, 

 however, taking a wheat field as an illustration, it is 

 impossible to cultivate the soil because the plants cover 

 the surface of the ground closely. What can and 

 should be done is to till the soil as deep as possible be- 

 fore planting and harrow after the plants are up, say 

 two or three inches. If any other sort of cultivation 

 is attempted the wheat and other grain must be cul- 

 tivated as in corn, by being planted in rows. The 

 production per acre would be greater than when sown 

 broadcast or drilled, but that method is not convenient, 

 at least it is not in vogue in the United States, and 

 probably never will be in large field culture, it being 

 easier and less laborious to flood the soil with water 

 to create the requisite amount of moisture. 



But in the case of vegetables, roots and tubers 

 there is no excuse for not aerating the soil, since these 

 plants can not be planted so close together as to en- 

 tirely cover the ground, except in the last stages of 

 their leaf growth, when the crop is assured. Running 

 ground vines even may be cultivated almost to the 

 point of ripeness, and when, as in the case of water- 

 melons, cucumbers and the like, or strawberries, the 

 vines have covered the ground, .a few rills of water 

 permitted to find their own way beneath is better than 

 a flooding, for the latter is apt to reach the stalks or 

 stems and either rot them or bake the ground and 

 choke off the air, thus killing the crop or injuring it 

 materially. All this can be provided for at the last 

 run of the cultivator, or stirring of the hoe, by leaving 

 small furrows or depressions here and there for the 

 water to run in as channels when cultivation is no 

 longer possible without tearing up the plants. 



VEGETABLES. 



Potatoes and tubers generally favor a moist, cool 

 soil, although in the arid regions under a very hot sun 



