CEREAL INVESTIGATIONS ON THE BELLE FOURCHE FARM. 3 
explained by the large percentage of clay and silt it contains, these 
amounting to 35 and 43.2 per cent, respectively. 
TaBLE I.—Composition of Pierre clay, as determined by mechanical analysis. 
Per cent. 
IR MeNCr aN Olen emer ries es ie ciuay OW a5 fen Ue ae ee renee 0. 2 
C@ oansegsein resem ee es os woe ee ge NT Ue i IR ae ile 
IMIS GI TOG SENN, eee les seem Me aaa cack ea ene CU ARN Nua isd! 
TEYEO®) GENNGL . oigSis Se She is Se ces es a Renn eee eke i i, 5) 
WY GURY? MEMOS TSENG NE he Ls A fe ea en epee nee nae aN, Ae Sty 13.0 
PUB ee a 0 set seek ER ere pee aS i ea AR Y 
Oy aN a Rane BM eC Pe Sarees ies anon css can) pep aside 35. 0 
The soil is a very heavy, stiff, impervious residual clay. It is 
somewhat deficient in humus, but is probably well supplied with the 
mineral elements of plant food. The imperviousness of the soil and 
the topography of the country cause considerable loss of water by 
run-off during heavy rains. 
Plowing is difficult and expensive. Other necessary field opera- 
tions, such as disking, harrowing, etc., are accomplished without 
difficulty. If these operations are performed at favorable times, the 
soil is easily put in excellent condition. 
There is considerable variation in the soil on the experiment farm, 
even within the limits of a single field. As a general rule, the higher 
land is lighter in texture, better supphed with humus, and more 
productive. The lower land is heavier, more impervious to water, 
contains less humus, and is more difficult to work and to get into 
condition for cropping. 
NATIVE VEGETATION. 
The native vegetation of the locality consists largely of western 
wheat-grass (Agropyron snuthu, A. occidentale) and buffalo grass 
(Bulbilis dactyloides). Grama grass (Bouteloua oligostachya) and 
needle grass (Stipa comata) are frequently found. Buffalo grass 
usually occupies the higher and lighter soils, especially where Pierre 
clay is the soil type. Western wheat-grass is confined mostly to the 
lower slopes and bottoms. On bottom lands subject to overflow this 
erass produces considerable hay of excellent quality. 
Weeds, such as sunflower (Helianthus petiolaris), gum weed (Grin- 
delia squarrosa), goosefoot (Atriplex volutans), and wild parsley 
(Peucedanum foeniculaceum), are plentiful. They are particularly 
abundant following extremely dry seasons, when the grass may be 
so injured that weeds are practically the only vegetation. Marsh 
elder (Iva axillaris) is of considerable economic importance because 
of the difficulty of eradicating it in cultivated fields. This plant 
commonly is called gumbo weed in this locality because it is found 
usually on the more impervious soils of the Pierre-clay type. 
