318 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



ments are not in the soil in available 

 form they must be applied. It is not only 

 necessary that they be present in the 

 soil, but they must be in a soluble form, 

 for in such form only can plants make 

 use of them. Some kinds of fertilizers 

 dissolve readily when applied to the soil. 

 There are other kinds that become avail- 

 able gradually and some others that are 

 so nearly insoluble that most plants can- 

 not make use of them. The apple, being 

 a long lived crop, can make use of the 

 slow working fertilizers, but the tendency 

 among careful apple growers is to use sol- 

 uble fertilizers and apply them just when 

 needed. The experienced apple grower 

 who keeps a close watch of his trees will 

 probably get best results from soluble fer- 

 tilizers, but the average farmer will do 

 well to adhere to the use of fertilizers 

 that become available gradually. 



C. D. Jarvi.s. 

 Storrs. Conn. 



Bearing Orchards 



The fertilizing of bearing orchards sel- 

 dom receives adequate attention. Bear- 

 ing trees in the crops removed make 

 heavy drafts on the elements of plant 

 food in the soil. The most important 

 elements which are removed are nitro- 

 gen, potash, and phosphoric acid. Rob- 

 erts*, in an experimental study of the 

 question, found that allowing 35 trees 

 to an acre, and a yield of 15 bushels to 

 a tree, the plant food removed in 20 

 crops of apples, and the leaves tor the 

 same period amounted in round numbers 

 to 1,337 pounds of nitrogen, 3in pounds 

 of phosphoric acid, and 1.S95 pounds of 

 potash. Comparing the amounts used 

 with those required by ordinary wheat 

 crops (15 bushels per acre and 35 pounds 

 of straw ) , for an equal length of time, 

 the apples removed practically three 

 times the quantity of jiotash, half again 

 as much phosphoric acid, and twice as 

 much nitrogen. 



The roots of a tree are constantly ex- 

 tending over a larger area, but it is plain 

 that if we would maintain our trees in 

 the best condition and improve the aver- 



• Itoherts. "Soil Depletion in Respect to the 

 Care of Ti-ees." Cornell Experiment Station 

 Bulletin 108. 



age size of fruit from year to year, we 

 cannot neglect attention to this matter. 



The tendency of increased feeding, es- 

 pecially in connection with thinning of 

 the fruit, would be to do away with "off 

 years," and reduce the damage due to 

 insects and fungi. It is a noticeable fact 

 that vigorous trees do not suffer from 

 the attacks of these organisms as much 

 as those which have been more or less 

 enfeebled from some unfavorable condi- 

 tion or circumstance. In good soils trees 

 will get along for some years, but after 

 bearing begins it is only a few years 

 before the trees will begin to feel the 

 need of plant food to compensate for that 

 removed. Of these nitrogen is most 

 cheaply supplied by means of good tillage 

 and the judicious use of green manures, 

 like cowpeas, and winter covers of vetch 

 and rye. Diminished growth and pale- 

 ness in the color of foliage are to a con- 

 siderable extent guides in determining 

 the need of nitrogen. Frequently too 

 much dependence is placed on the vir- 

 tues of legumes to the exclusion of appli- 

 cations of other fertilizers. Excess of 

 nitrogen should be avoided. There should 

 be a balanced "ration." In the case of 

 bearing trees applications of potash are 

 called for; also of phosphoric acid. Cow- 

 peas do not increase the supply of these 

 elements as they do of nitrogen. 



Stable Manures 



Practical men report excellent results 

 from the use of stable manures. There 

 is no objection to their reasonable use on 

 apples. Commercial fertilizers may sup- 

 ply the same manurial elements in less 

 bulk and with relatively greater profit. 

 But especially on the lighter soils humus 

 is needed, so it is well to make use of all 

 the methods of supplying the elements 

 needed. A good plan would be to let 

 an application of stable manure — 20 to 

 25 tons per acre — take the place of leg- 

 umes once in four or five years. Whether 

 the leguminous crops are kept up annu- 

 ally in the interval will depend on the 

 needs of the trees. An application of 

 50 to 100 pounds of nitrate of soda per 

 acre just before the growing season might 

 be desirable under conditions where there 



