36 BULLETIN 353, U. S. DEPARTMENT OF AGRICULTURE. 
SUMMARY. 
The variation in moisture content in field-cured forage often gives 
rise to errors greater in amount than the differences in yield between 
improved varieties or different methods of culture. 
A study of the use of samples in correcting forage yields indicates 
the following results: 
(1) Air-dried samples are a little less accurate than oven-dried samples, but the 
difference is so small that the air drying of samples can be relied upon for all prac- 
tical purposes in correcting forage yields. 
(2) Much greater extremes are found in the samples of field-cured material than 
in the samples of green material, indicating that replication of samples is more 
important in the former than in the latter. 
(3) Corrections by means of samples can be accurately made from either green or 
field-cured material, provided care is used in sampling. 
(4) Considering accuracy of results, facility of handling, and ease in figuring per- 
centages, 5-pound samples of field-cured material and 10-pound samples of green 
material are recommended as the most desirable sizes for practical use. 
(5) Samples need not be replicated more than three times. 
(6) The percentage of moisture in the different crops at that period of growth when 
they are ordinarily harvested for forage was as follows: Alfalfa at Chico, Cal., 75 to 
78 per cent; average, 76.9 percent. Alfalfa at Arlington Farm, Va., 74 to 76.5 per cent; 
average, 75.2 percent. ‘Tall oat-grass and orchard-grass mixture at Arlington Farm, 
Va., 71 to 73 per cent; average, 72 per cent. Timothy at New London, Ohio, when 
in full bloom, average, 67.2 per cent. Sorghum at Amarillo, Tex., 70 to 73 per cent; 
average, 71.2 per cent. These percentages are probably near the average for each crop, 
but the fact that McKee found 85.8 per cent and Farrell an estimated 79.5 per cent of 
moisture in alfalfa indicates that it will be impossible to establish any arbitrary 
percentage of moisture in the green plant as a basis for correcting forage yields. 
(7) The average amount of moisture in field-cured material was as follows: Alfalfa, 
22.3 per cent; timothy, 20.3 per cent; tall oat-grass and orchard-grass mixture, 29 per 
cent; sorghum, 43.2 per cent. The moisture content of field-cured material varies so 
widely that it can not be foretold with accuracy. 
The use of the sample method in correcting forage yields would 
sreatly assist in standardizing agronomic data and do much to 
promote greater accuracy in field tests. 
The system of correcting yield data by the use of air-dried samples 
is of most value in succulent crops lke sorghum and Sudan grass 
and is of least value in fine-stemmed plants lke millet, which cure 
quickly and rather completely. 
The relation of the moisture content to the stage of development 
in the plants was studied in alfalfa, timothy, and sorghum. The 
results were as follows: 
(1) Alfalfa at Chico, Cal.: Very young (12 inches high), 78.9 per cent; one-tenth 
in bloom, 77.1 per cent; full bloom, 74.6 per cent; past full bloom, 73.4 per cent. 
(2) Sorghum at Amarillo, Tex.: Very young, 90.6 per cent; shooting for heads, 
87.1 per cent; beginning to head, 84.8 per cent; full bloom, 80.4 per cent; seed ripe, 
75.3 per cent. 
(3) Sorghum at Hays, Kans., varied from 89.2 per cent when very young to 73.2 
per cent when seed was ripe, showing practically the same gradations as at Amarillo, 
Tex. : 
