404 STATE HORTICULTURAL SOCIETY. 



illustrate, in a given weight of growing peach twigs, leaves included, there 

 is more lime in June than in April, more in August than in June, and more 

 in October than in August. The reverse of these statements holds good for 

 potash and phosphoric acid, the young and actively growing shoots being 

 gorged with compounds of potassium and phosphorus, which decrease in 

 quantity as growth progresses, until they reach an amount normal for the 

 mature growths of the plant in question. The growth under the influence 

 of peach yellows appears to be no exception to this rule. The amount of 

 lime increases and the amount of potash and phosphoric acid diminishes 

 in the ash in proportion as the growths approach maturity. They never 

 reach the same robustness or degree of maturity as healthy shoots, and 

 consequently might be expected to contain less lime and more K 2 and 

 Po0 5 than healthy shoots of a corresponding age. It would appear from 

 the analyses by the Connecticut station, and from Professor Eastwood's 

 determinations, that diseased shoots contain absolutely less ash than nor- 

 mal shoots, which is also what we should expect. 



In conclusion, it may be remarked ( 1 ) that there are not yet enough 

 analyses of the peach itself to make comparative studies of the fruit of 

 any value, and (2) that all analyses of this kind are quite open to the 

 criticis)n that they can rarely be actually comparative, and therefore have- 

 only a very moderate value. 



I now invite your attention to some field experiments. 



FIELD WOEK. 



For three years the department of agriculture has carried on, in the 

 peach yellows region of Maryland and Delaware, a series of experiments 

 using chemical fertilizers. Some of these experiments have followed the 

 lines laid down by Dr. Goessman and Professor Penhallow. The entire 

 series includes over forty acres of treated trees, selected from a dozen 

 orchards in two counties, with more than one hundred acres held for com- 

 parison. A synopsis of these experiments will be published by the depart- 

 ment of agriculture, and it is my purpose here to present only one set. but 

 enough to show that the chemical or starvation theory of peach yellows 

 breaks down when put to actual and practical test in the peach orchards. 



For this set of experiments, which I shall designate the Goessman- 

 Penhallow treatment, 340 trees were selected in the middle of one of the 

 finest peach orchards in Delaware. This orchard contains thirty acres. 

 It was planted in 1882, received constant care, grew thriftily, and was 

 practically free from yellows until 1887. The trees selected for treatment 

 and for control were of quite uniform growth and appearance. They stood 

 at a uniform distance (20 x 20 ft.), upon level and very uniform soil, con- 

 sisting of six to nine inches of sandy loam, resting on a porous yellow 

 clay. Samples of the soil and subsoil of this orchard were exhibited. The 

 original timber of this farm was a heavy growth of oak, tulip tree, walnut, 

 sassafras, holly, and gum. The soil has been in cultivation many years. The 

 wheat product of this farm now averages about thirty bushels per acre with 

 a moderate amount of phosphate, and the corn crop. about sixty bushels. 

 Apple trees on the same farm reach a large size and are productive. 



The experimental plats were .numbered A to D and arranged as shown 

 in the following diagram, 100 trees, separating A B from C D, being used 

 for comparison. 



