162 



THE IRRIGATION AGE. 



under irrigation and the very lack of care has given us 

 great faith in what may be done by correct methods. 



The interest of our people has been in cows, not 

 trees; in sheep rather than in shade. With development, 

 we are losing interest in the range to a large extent and 

 centering it in the home. Now we need to know more 

 of the indulging principles that will guide us in our prac- 

 tice under our varying conditions. Because one man gets 

 apples with a single irrigation and another gets a crop 

 by applying eight irrigations is no reason for a third 

 using either one or eight applications of water. Why 

 do we apply water anyway and what does more or less 

 of it do to the growing or to the dormant plant? It is 

 not unreasonable to ask that the state and the general 

 government put forth more effort to solve these ques 

 tions. 



Irrigation and Plant Food. 



We seldom think, perhaps, of the relation of the food 

 supply to the life of the plant as we do in rearing animals. 

 The statement has been often made by live stock breed- 

 ers that the "corn crib is the best mother," and all suc- 

 cessful animal feeders understand the importance of 

 a balanced ration. A rich and nutritious soil solution con- 

 taining the right proportion of the different plant foods 

 is of as much importance to the individual plant and 

 to the collective crop as is the full corn crib and balanced 

 ration to the growing calf and the increasing herd. 



By limiting the food supply the Japanese have 

 dwarfed giant kinds of trees. We dwarf apple and pear 

 trees by using small or slow growing stocks to limit the 

 supply of food to the scion. Some animals are consti- 

 tutionally good feeders and in like manner there are in- 

 herent feeding qualities in plant varieties. It is well 

 known that rye or buckwheat will gather food from poorer 

 .-soils than other grains. One of the more important 

 economic achievements of Burbank, is in the great grow- 

 ing force or power which he secures in his productions. 

 To secure a maximum growth, there must be an abundant 

 and available food supply in the soil. We also vary the 

 balance of the ration to secure large vegetative growth 

 or a larger production of seeds and fruit. 



Many of the life processes of animals are reversed 

 in plants. Higher animals take food through their heads, 

 higher plants through their feet. The animal takes solid 

 food which must be organic, the plant never uses any- 

 thing but liquid or gaseous food which is usually simple 

 and inorganic. Animals digest their food on the inside 

 and burn it to produce heat, the plant digests its food on 

 the outside by the influence of light on the leaves and 

 reverses the burning process. The animal needs a prac- 

 tically continuous supply, whereas the plant feeds in 

 seasons with long dormant periods of rest. The food of 

 animals is in sight, tangible and known, and the food of 

 plants is in the soil, out of sight, intangible and unknown 

 save through the mind's eye of the observer who notes 

 its effect on growth or to the chemist. 



These are all simple statements and known to every- 

 one, so it might seem like a loss of time to reiterate them, 

 but you will agree with me that we know too little of the 

 basic principles underlying our practice and we may 

 make use continually of all this kind of knowledge we 

 can obtain. 



The plant then takes its food and drink together. 

 Most plants can not even absorb water through their 

 parts above ground they obtain it with the soil solution 

 and the strength of this solution varies with every factor 

 which influences the character of the soil and its mois- 

 ture content. It is pretty well settled in my own mind 

 that the strength of the soil solution is the rnain factor 

 which determines the amount of water used by a plant in 

 its growth and maturity, though this relationship has 

 never been studied. Those who have investigated the 

 nmount of water used by the plant in its growth, have 

 ignored the character and amount of plant food which 

 might be carried with it. The plant physiologist has be- 

 lieved in selective absorption, but where the chemist and 

 physicist has investigated, it appears that absorption is 

 purely mechanical, i. e., it is osmotic. If a poison gets 

 into the soil, the plant absorbs it and commits involun- 

 tary suicide as shown in Colorado, where Dr. Headden 

 discovered that arsenic used in spraying has killed many 

 trees. In our investigations of alkali, Professor E. E. 



Slosson and myself found that the amounts of salt solu- 

 tion absorbed by plants were inversely proportional to 

 the strength (measured in osmotic pressure) of the salts 

 in the solution. This being true, the strength of the 

 solution must directly affect the feeding and nutrition of 

 plants. One investigator found that it took 912 pounds 

 of water transpired by the plant to produce one pound 

 of growth. Another investigator found that 225 pounds 

 were used. It would, be interesting to know and especial- 

 ly by us here in the West, where we manage the water 

 supply of the soil through irrigation or conservation, 

 whether the thickness of the soup used by the plant does 

 not determine the amount of it needed to satisfy vegetable 

 hunger. If this is true, less water is needed in the arid 

 region to produce growth than will be required where 

 rainfall has leached out a portion of the soil salts. 



It is through the control and management of the 

 food supply that we can exert such perfect control over 

 our orchards in the west by our use of irrigation and 

 keeping the underlying principle in mind, will help us in 

 practice. Our soils are lastingly rich in the mineral plant 

 foods which are so important in the formation of wood, 

 fruit and seed. If there is too much soluble salt in the 

 soil, we may add some amendment that will make it less 

 soluble as does the California orchardist when he adds 

 gypsum to correct the effect of "black alkali," or we 

 may add drainage and cultivation so too much of the 

 salt will not stand in solution or we may wash out the 

 surplus salts by using abundance of water. Generally on 

 our good soils we need only to apply water when we 

 would have the trees make growth or withhold it when 

 we want them to mature or become dormant. If the soil 

 should remain too wet, we may use a quickly growing 

 cover crop to pump out the surplus moisture. I have 

 no doubt that the lack of clean culture in some of our 

 orchards has been a blessing in disguise to automatically 

 overcome the deleterious effect of too much irrigation. 

 We undoubtedly make many mistakes in the time and 

 amount of irrigation and it will take much experience and 

 study to overcome them. 



Irrigation and Orchard Control. 



Erasmus Darwin, the early agricultural poet and 

 grandfather of Charles Darwin, pointed out that the bud 

 is the individual in plant life. It is the development, ma- 

 turity and welfare of the bud that is of most concern to 

 the orchardist. If the buds ripen and put on enough 

 overcoats to protect them through our long winters, there 

 is little danger that loss will be incurred by cold and 

 storm. Correct management of the irrigation of our trees 

 secures maturity of the buds and ripening of the season's 

 growth of wood. 



Too much irrigation during the latter part of summer 

 and early fall is undoubtedly a frequent cause of winter 

 killing of trees. After the season is so far advanced that 

 new growth will not be produced, the orchard soil should 

 be filled with water to prevent injury from winter drouth. 



Another important factor in frost control is the pos- 

 sibility of preventing injury to the fruit buds in spring 

 by keeping the orchard wet during the danger period. 

 Enough latent heat is given out by the standing water 

 to prevent killing the blossoms except in very severe 

 frosts. 



All too often the man with a small home orchard and 

 plenty of water to use substitutes irrigation for cultiva- 

 tion. The arguments for clean culture are too numerous 

 and weighty, however, to permit of any other practice. 

 Of course this does not interfere with the growing of 

 short period cover crops of legumes to gather nitrogen 

 and add humus to our orchard soils, 



Until such time as we shall breed more stability and 

 fixity into our fruits to produce' adapted varieties which 

 ivill be at home in our western environment, the fruit 

 raiser under irrigation must expect considerable variation 

 in his product. Fortunately the result of pur rich soils 

 and the stimulation given plants by the artificial applica- 

 tion of water is increase in productiveness, size and other 

 qualities and with skilful treatment and the application of 

 plant breeding methods we have great opportunities to 

 improve varieties for our own conditions. With our 

 soils, climate and irrigation, the mountain region of the 

 west by force of favorable natural conditions will lead im 

 the production of more important farm crops and fruits. 



