9 BULLETIN 297, U. S. DEPARTMENT OF AGRICULTURE. 
The results of the experiments for six years (1908-1913) are here 
reported. So short a period is entirely inadequate to settle many of 
the problems of dry-land grain production. However, a presenta- 
tion of the results obtained should be of assistance to those engaged 
in similar work. . 
DESCRIPTION OF THE FIELD STATION. 
It is believed that the results here reported are applicable in general 
to western South Dakota, northeastern Wyoming, and southeastern 
Montana. The variations in soil and climate within this section, 
however, are considerable. To determine just how far the results 
obtained at Newell are applicable to any other locality, a comparison 
of soil and chmatic conditions is necessary. In order to permit such 
a comparison, a description of the field station is here given, together 
with detailed information regarding the temperature and the amount 
and distribution of the rainfall during the period covered by the 
experiments. 
LOCATION. 
The Belle Fourche Experiment Farm is located near the center of 
the Belle Fourche Reclamation Project, in western South Dakota. 
The farm is about 24 miles northeast of Bellefourche and 2 miles 
northwest of Newell. The latitude is about 44° 43’ 45’’ N. and the 
longitude 103° 26’ 15’’ W. The elevation is approximately 2,950 
feet. About one-half of the farm is irrigated. The portion which 
is above the irrigation ditch is used for dry-land experiments, includ- 
ing those here reported. The topography of the farm and of the 
surrounding country is rolling, affording good drainage at all times. 
GENERAL PHYSICAL FACTORS. 
A study of the crop yields for the series of years here presented 
may be made more intelligently if combined with a knowledge of the 
factors which have influenced crop growth. The most important 
physical factors are (1) the soil, (2) the rainfall and its distribution, 
and (3) the temperature, especially the length of the growing season 
as limited by spring and fall frosts. These and other physical data 
for the Belle Fourche farm are summarized in the paragraphs which 
follow. 
SOIL. 
The soil of the Belle.Fourche farm and surrounding area is mapped 
as Pierre clay by the Bureau of Soils.t. To stockmen and farmers it 
is familiarly known as gumbo. ‘Table I shows the results of a mechan- 
ical analysis of Pierre clay. Its characteristic stickiness is perhaps 
1Strahorn, A. T., and Mann, C. W. Soil survey of the Belle Fourche area, South Dakota. In U.S. 
Dept. Agr., Bur. Soils Field Oper., 9th Rept., 1907, p. 888. 1909. 
