Vol. XXVIII 
MAY 10, 1924 
No. 6 
JOURNAL OF 
AGRICULTURAL 
RESEARCH 
CONTENTS 
■- A Page. 
Factors Influencing the Binding Power of Soil Colloids - - - - 499 
HOWARD E. MIDDLETON 
The Genetic Relation between Triticum dicoccum dicoccoides and a Similar Mor¬ 
phological Type Produced Synthetically - - - S15 
, H. H. LOVE and W. T. CRAIG 
Bud Selection as Related to Quality of Crop in the Washington Navel Orange - - 521 
A. D. SHAMEL, Cl S. POMEROY, and R. E. CARYL 
The Determination of Nitrate and Ammonia in Nitrogenous Materials - - - 527 
• ■ O. M. SHEDD 
Puccinia graminis poae Erikss. and Henn. in the United States - ^ - - 541 
E. C. STAKMAN and M. N. LEVINE 
Relation of Soil Temperature and Soil Moisture to Infection by Plasmodiophofa 
brassicae - ■ - - . - ■ - - - - - - 549 
. JOHN MONTEITH, Jr. ' - . 
Length of Cotton Fiber from Bolls at Different Heights on the Plant - - - 563 
THOMAS H EEAS.NET a-v. GEORGE J. HARRISON 
“Hairy Neck” Wheat Segregates from Wheat-Rye Hybrids - - - - 567 
CLYDE 1; LEIGHTY and J W. TAYLOR 
Ascaris Sebsitization - - - - - ’ - .- - - - - 57? 
B.H. RANSOM, W. T, HARRISON, and J, F. COUCH ; 
Physalospora malorum on Currant - - - - - •- v . - - - 583 
. . NEIL E. STEVENS 
Botryosphaeria and Physalospora on Currant and Apple - - - - - 589 
C. L. SHEAR, NEIL E. STEVENS, and MARGUERITE S. WILCOX ' : 
Isolation of an Inhibitory Substance from Plants - 7 f ‘ . - - - A 599 
W, i„ MALLMANN snd CARL HEMSTREET 
Two Hitherto Unreported Diseases of Stone Fruits - - - -> 603 
, C. C. LINDEGREN and DEAN H. ROSE ' 
PUBLISHED BY AUTHORITY OF THE SECRETARY OF AGRICULTURE 
WITH THE COOPERATION OF THE ASSOCIATION 
OF LAND-GRANT COLLEGES 
WASHINGTON, D. C. 
GOVERNMENT PRINTING OFFICE 
1024 ■ 
