UNITED STATES DEPARTMENT OF AGRICULTURE 
Contribution from the Bureau of Plant Indusiry 
WM. A. TAYLOR, Chief 
Washington, D. C. PROFESSIONAL PAPER March 16, 1916 
MOISTURE CONTENT AND SHRINKAGE OF FORAGE AND 
THE RELATION OF THESE FACTORS TO THE ACCURACY 
OF EXPERIMENTAL DATA. 
By H. N. Vinauu, Agronomist, and Rotanp McKEs, Assistant Agrostologist, Office of 
Forage-Crop Investigations.+ 
CONTENTS. 
: Page. Page 
Introduction esses eee ene ene a ae ek es 1 | Variation in the moisture content of growing 
General plan of the experiments.........-.-- 2 alfalfa during a single day...-............-- 31 
Use of samples in correcting forage yields... 3 | Moisture content of baled hay............... 31 
Relation of the stage of growth of forage plants Shrinkage of hay after storing and variation in 
to their moisture content.................: 22 weight due to changes in atmospheric hu- 
Loss of moisture in forage during the early PROW EG BA Eig Se A sR a a ce a are ee 32 
Stazesiohcuringssie ste. sano e ene =] Seles 273 | SSuMM aye Ea ae Nee ed ae ee eee 36 
INTRODUCTION. 
Agronomic literature contains but little in the way of well-planned 
investigations on the subject of the moisture content of different 
forage plants either green or cured, a matter which is mtimately 
related in farm practice to the proper handling and wise marketing 
of forage crops and in investigational work to the correct interpreta- 
tion of yield data. This subject is of sufficient importance to justify 
much more attention than has previously been given to it by experi- 
menters. Careful investigators have long recognized that many of 
the published data on forage crops are inaccurate, on account of the 
uncertain amount of water included in the yields. 
The term ‘‘air dry,”’ as used in the investigations described in the 
following pages, refers to that stage of curing when the humidity of 
the forage and the humidity of the atmosphere have reached a state 
of equilibrium. The percentage of moisture in the forage when 
air dry of course varies with the changes in atmospheric humidity, 
1 Messrs. W. J. Morse, H. L. Westover, M. W. Evans, A. B. Cron, and R. E. Getty, members of the 
staff of the Office of Forage-Crop Investigations, have contributed quite largely to this publication by 
their assistance in collecting and preparing records of the numerous samples required. 
21216°—Bull. 353—16——1 
