46 



SCIENTIFIC AGRICULTURE 



October 



death at two and one-half pounds. When 

 used in conjunction with nitrate the evil 

 effects were ameliorated but more pro- 

 nounced when used with slag. His results 

 with sulphate of potash showed that larger 

 amounts could be u.sed without injury but 

 in no case did benefits accrue. 



►Stewart in Pennsylvania records similar 

 results on .some soils and beneficial results 

 on others. 



This evidence is very conflicting when 

 compai-ed with our former conception of 

 the necessity of yearly applications of 

 potasli on practically all orchards. Now 

 do not gather from this that potash is 

 not useful as a fertilizer, for it undoub- 

 tedly- is. The point the writer wishes to im- 

 press is that until b.y experimentation 

 it has been shown in your district that 

 your soils are deficient in this element 

 the use should be practised with caution. 

 Potash is found in fairly large amounts in 

 many soils and is a much more stable pro- 

 duct than nitrogen which is usualh' lack- 

 ing, especially in sandy or lighter soils. 

 Hence it is quite probable that many of 

 the orchards in the valleys have a suffi- 

 cient supply of potasii for some few years 

 to meet the demands of the trees. 



Phosphorous has a distinct position in 

 ordinary farm crops and is likewise a ne- 

 cessity in the production of fruit. Although 

 the average soil is probably more deficient 

 in phosphate than in potash, nevertheless 

 conflicting results from its use have been 

 obtained, although not to such a marked 

 degree as witli potash. If the soil is de- 

 ficient in this element it should certainly 

 be made up, but beyond this it is im]K)ssible 

 to make any recommendations, except to 

 urge upon each orcliardist for the time 

 being the advisability of turning a small 

 coiner of his orehai-d into a fertilizer test 

 plot. 



In shoi't you would do well to turn yonr 

 attention to the value of nitrogen as an 

 early spi-ing ap])lication and to study the 

 growth of your trees and attempt to es- 

 tablish that necessary balance between ni- 

 trates and carbohydrates, holding in re- 

 serve in the meantime your judgment on 

 potash and phos])bates uidess you ai'e fully 

 convin<'('d that yonr sc-il is imi)overished in 

 these elements. 



The recent findings witli regai'd to frnit 



bud formation have assisted materially in 

 a better understanding of the fertilizer 

 and pruning problem. A number of in- 

 vestigators have given this problem consi- 

 derable attention, and the sum total of all 

 their findings, although not complete, has 

 presented this phase to us in a fairly com- 

 prehensive manner. 



One outstanding truth is that fruit bud 

 differentiation on spuis takes place fairly 

 early in the season. Roberts says July 5 

 and previous to that date. Crow found last 

 year that his experiments indicated no pos- 

 sibility of influencing fruit bud differen- 

 tiation after the trees were in full bloom. 

 Roberts is drawing his conclusions from 

 the fact that July 5 was the date when 

 microscopic .slides first showed differentia- 

 tion between vegetative and fruit spurs. 



Crow removed all the blossoms from 

 some branches producing heavy bloom and 

 then observed spur growth, making his ob- 

 servations on tlie basis of the types of 

 spurs defined by Roberts the previous year. 



These types of spurs are : 



(1) Short spurs averaging Vh inch; these 

 produce only leaf buds, 



(2) Spurs averaging 3/16 inch, and 

 which blossom but do not fruit. 



(3) Spurs averaging I/2 ^^^^ which blos- 

 som and fruit. 



(4) Long spurs averaging % inch in 

 length and over, which do not blossom or 

 fruit. 



On the branches wliicli were allowed to 

 bloom heavily all the spurs formed dui-ing 

 1920, that is the year of the heavy bloom, 

 fell into the short fruit spur and long leaf 

 spur classes. That is, these spurs would not 

 fruit the following year. 



AVhere tlie blossom clusters were re- 

 moved two or tliree days before the first 

 petals began to fall, he was able to throw 

 a very large i)ercentage of these short spur 

 gnnvths into the strong spur class and 

 tliese would fruit the following year. 



AVlien ])lossom clusters were removed 

 after the first j)etals began to fall no in- 

 crease in the formation of strong fruit 

 spurs over the check could be observed. 

 From this it would seem that any treat- 

 ment designed to increase fruit bud fornui- 

 tion or differentiation should be made 

 early in the season. 



This is not contradictoi-v to Roberts bnt 



