1919] Colt-Hodgson : Abnormal Shedding of Washington Navel Orange 287 



mercial fertilizers are given. The roots of the trees fully occupy all 

 of the middle spaces, and appear exceptionally healthy and vigorous. 

 A large number of healthy roots were taken from a hole dug at the 

 center of a square formed by four trees. The vertical distribution of 

 roots is good. A hole two feet square was dug to the southwest of a 

 tree well beyond the spread of the branches. Each six-inch soil layer 

 was kept separate and the roots sifted out. On account of the dryness 

 of the air comparative weights were not made, but the root distribution 

 between the second and sixth six-inch layer is well shown in plate 42. 



The general health and appearance of the trees at the Kellogg orchard 

 is in every way similar to that at Edison. The orchard is one year 

 younger than the plot used in the experimental work at Edison, but 

 there is no appreciable difference in the size of the trees, unless it be 

 in favor of the trees at the Kellogg place, which is to be explained 

 as due to the method of handling the orchard. 



Soil conditions are fairly similar, except that the surface soil at 

 Edison is considerably heavier and more compact than at East Bakers- 

 field, where the soil would be classified as a medium sand. However, 

 it becomes heavier as one goes down until, at a depth of two feet, there 

 is no noticeable difference in the soil at the two stations. We are not 

 able to present analyses of this soil as to plant food, but there is no 

 reason to believe that it differs markedly from that at Edison. 



A radical difference, however, is manifest in the management of 

 the two orchards. The main part of the Kellogg orchard is planted 

 to alfalfa (pi. 26), and the portions in which our experimental work 

 was done have had alfalfa grown between the trees for three or four 

 years. Before planting the alfalfa the orchard was carefully and 

 effectively laid out in small checks draining one into the other. The 

 trees are protected from having water standing about their trunks by 

 ridges thrown up just under the drip of the trees. These checks as 

 well as the ridges are occupied by a good stand of alfalfa, which is 

 cut for hay and hauled off. Irrigation water is pumped from wells 

 and is applied in copious amounts, the period between irrigations 

 averaging about three weeks, or a week to ten days shorter than that 

 at Edison. There can hardly be any doubt but that considerably more 

 water is applied to these trees than at Edison. Applications of com- 

 mercial fertilizers have been made to the orchard from time to time 

 No detailed study of the root distribution was made but a few holes 

 dug for other purposes seemed to indicate that the roots tend to go 

 down or away from the surface in this orchard rather than to be 

 localized in the upper soil layers. 



