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ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



and particles of earth that the roots 

 would not penetrate unless broken up. 

 For instance, a rock contains many con- 

 stituents necessary to plant growth, but 

 as rock it is not available as food. Pul- 

 verize the rock and moisten its particles 

 and the roots will drink in their chemi- 

 cals. The same is true of clods and of 

 fertilizers. The breaking up, the eroding, 

 the mixing of the harder substances un- 

 til they are fully pulverized, render them 

 soluble and make it possible for the roots 

 to take their food in solution very much 

 as human beings take food in the form 

 of soup. 



Weeds — Weeds also absorb moisture, 

 and because they compete with the trees 

 for something to eat they should be de- 

 stroyed and the food given to the trees. 



Irrigated Sections 



In irrigated districts, where abundant 

 water is supplied, the question of mois- 

 ture is not so important. However, irriga- 

 tion does not pulverize the soil and does 

 not keep down the weeds. In fact, it 

 cannot be profitably substituted for culti- 

 vation however much it may render un- 

 necessary cultivation to conserve mois- 

 ture. Our motto is. Drainage for wet 

 lands and dust mulch for dry lands. 



I»eei» Plowing for Large Trees 



The question of deep plowing for large 

 trees in the orchard has been a mooted 

 question. We have taken both sides of 

 this question. 



First, we favored deep plowing, think- 

 ing that it would be better to turn under 

 a coating of barnyard manure and throw 

 up the hard sub-soil. We did this, and 

 tore up so many of the little roots of 

 the trees that we believed we had in- 

 jured the orchard. It seemed to us im- 

 possible for the tree to have its root 

 system thus disturbed without injury. 

 However, we had pruned rather heavily 

 that year, and the breaking of the roots 

 did not correspond in amount to the 

 cutting away of the tops. We watched 

 the trees carefully, and for the first year 

 saw nothing to indicate that they had 

 been either helped or injured. The sec- 

 ond year they seemed to take on new 

 vigor and the fruit was especially fine. 



This was doubtless due in part to the 

 coating of barn yard manure, but we 

 also think that the deep plowing where 

 the soil is deep and the roots can pene- 

 trate it easily may be beneficial. By 

 observation in other orchards, we have 

 reached the conclusion that when the 

 surface roots are broken, generally the 

 lower roots will sink more deeply into 

 the sub-soil, and that deep plowing is a 

 kind of root pruning. But often the roots 

 will not get sufficient moisture at the 

 greater depth, or the soil is so hard that 

 they cannot penetrate, and more or less 

 injury is done by deep- plowing. The 

 latest demonstrations have proven that 

 a great percentage of the feeding rootlets 

 are near the surface, and that most of 

 them are from one to two feet in depth. 

 The consensus of opinion is therefore 

 shifting in the direction of shallow in- 

 stead of deep cultivation for bearing or- 

 chards. At this writing the question is 

 a debatable one, and the probabilities 

 are that in some cases it is helpful but 

 in others injurious. (See Thee Roots.) 



Cover Crops 



What we have said in favor of cultiva- 

 tion is not intended to disparage or to 

 discourage the use of cover crops in or- 

 chards. In fact, experience has shown 

 that after an orchard has had clean cul- 

 tivation until the trees are reaching the 

 bearing period, the very best cultivation 

 they can have, provided there is sufficient 

 water, is the breaking up of the sub-soil 

 by the strong vigorous roots of alfalfa. 

 It is common for these roots to penetrate 

 the soil to a depth of 25 feet, and in some 

 places in a loose porous soil, as proven 

 by the Arizona Experiment Station, they 

 have gone to depth of 50 feet. They are 

 much more vigorous than the roots of 

 fruit trees, and in breaking up the hard 

 sub-stratum, they lead the water to 

 greater depth, and open up a new world 

 of plant food for the roots of the trees. 

 In the arid regions where irrigation is 

 practiced, and where the soil lacks hu- 

 mus, alfalfa, according to the best infor- 

 mation available now, is the very best 

 treatment for orchards set to apples and 

 pears. 



