2 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 chmate 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 climatic 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 winch 

 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 mtelligently 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. 1 To stockmen and farmers it 

 is familiarly known as gumbo. Table I shows t he results of a mechan- 

 ical analysis of Pierre clay. Its characteristic stickiness is perhaps 



■ Strahorn, V. T., and Mann, C. W. Soil survey of Hie Belle Fourche area, South Dakota. In U. S. 

 Dcpt. Agr., Bur. Soils Field Oper., sith Kept., l'J07, p. sns. W09. 



