Table 1.--Standard Partial Regression Coefficients and Multiple Correlations (R) of 
Factors Related to Grazing Yields or Grain Yields of Wheat, n= 884. 
Regression coefficients for-- 
Factor 
Forage yield Grain yield 
(Cwt. per Acre)| (Bu. per Acre) 
Grazing Yield, (Cwt. per Acre).........-.-.-ee-eeeeees 008 
Soll, Tease, (ispelers)) boo occ0 cnc os 0G0 0c bo DOGDDuG0uG00N -.102%* 
Sea, (WSOEING) oo cco 00oD00000D50000G0099000000000000 -.057%* 
Amount of Tillage, (Inches Soil Stirred).............. ; - 120** 
Vesa Grorrtin, (Wilma, serine) 505 c00cosccasouncdnoo0b0 -.079%« 
IMsSCCeMminheSbatonwn avi sualemrating)icanee cece secs P -.617** 
Water Conservation Practices (Index)*.............ee0- =n0B5 
Sieiole Nieblela, Clalswall, senwlnes)—ooocsccccnssaocoouscens : -.070* 
Total Rainfall Grazing Period, (Inches)............... Sil 453 
Amount Weekly Rain (Prep. Period), (Inches) -.170** 
Amount Weekly Rain Grazing Period, (Inches) So Deer 
Initial Soil Moisture, (Depth-Inches)................. .341%* 
atenessmofe Plantings «(WEEKS)).1..siccc ccc ccc ces cre ccee - .057%* 
MeneuAwoteGrazanesPexrtod.y ((WEEKS))/c cls cis cc + clele <'e e+1e10« -.214%* 
R = .7413 
*Significant at 5-percent level. 
*xHighly significant at l-percent level. 
1 Rated numerically by soil class, 1 for clay and increasing number for each coarser 
textural class. 
2 Rated numerically, O or 1 for negligible magnitude and increase number for increasing 
intensity. 
OTHER FACTORS AFFECTING FORAGE AND GRAIN YIELDS 
Topsoil texture varied from clay loam to loamy sand. Soil texture did not signifi- 
cantly affect forage yield, but higher grain yields came from the finer textured soils. 
Land slopes ranged between 0.5 and 5 percent. Flatter lands produced highest yields 
of both grain and forage. Yields of forage were much lower (highly significantly so) on 
steep slopes, and grain yields were significantly lower there than on gentle slopes and 
flatlands. 
Amount of tillage performed in preparation for seeding was measured as a sum of 
inches of soil stirred by all preparatory field operations. It did not affect forage yield 
but was positively related to grain yield, probably a result of more adequate weed con- 
trol. 
Weed growth during preparatory period contributed to pasturage production to a 
highly significant extent, obviously because of the palatable nature of some of the weeds, 
but was strongly depressing to grain yield by reducing the moisture and fertility level in 
the soil. 
Degree of insect infestation varied widely between times and places but was severe 
enough occasionally to reduce grain yields. Pasturage was not greatly affected. Greenbug 
or green aphid (Toxoptera graminum) was the principal insect encountered. 
BBE 
