1912] BRIGGS & SHANTZ—WILTING COEFFICIENT 31 
examined is 2.90+0.06. The relationship between the wilting 
coefficient and the moisture holding capacity is then: 
Moisture holding capacity — 21 _ tin g coefficient. 
2.90.06 
TABLE IV 
RELATIONS OF THE WILTING COEFFICIENT TO THE MOISTURE HOLDING CAPACITY 
Moisture holding wn . — of postman: 
, a “a 
No Soil type peabmet| Wtae tertiee |. Nldinn coneeiy 
2 ge ad RSE Coarse sand 23.2 0.9 2.44 
P Maar a eee ine sand 29.9 2.6 3.40 
TE ee ee Fine sand 28.5 4.3 2.27 
Greve s: e sand Sry 2:6 2.84 
Piece ees Sandy loam 44 8.3 2.88 
GUE Sandy lo 50.1 0.5 3.06 
| Set ae am 55-9 II.0 S37 
Se ee am 58.6 11.6 3.24 
: Feueote eee 59.8 10.7 3.30 
Me ce ys Clay loam 54.2 13.8 2.40 
i ebage «per Clay loam 58.2 14.7 2.52 
¢ ER ee tC 8 Clay loam 63.2 14 2.83 
Mh sgvcy snare Clay loam We 5 15.0 8.35 
ane. ar Clay loam 67.2 wet ge 2.04 
2 ee Gee ee Clay loam 69.5 16.7 2.90 
OM ets 6258s 2.90 
Probable error of mean ratio ........ +0.06 
RELATION OF WILTING COEFFICIENT TO SOIL TEXTURE AS EXPRESSED 
Y MECHANICAL ANALYSIS 
Soil texture has been more extensively used than any other 
physical property for the quantitative description of soils, and 
unfortunately it has been one of the most difficult to interpret from 
the standpoint of moisture retentiveness. Texture is quantita- 
tively expressed by means of the mechanical analysis, which shows 
the composition of the soil when the particles are separated into 
groups according to size. The accuracy with which the texture of 
the soil can be expressed by this means is dependent upon the num- 
ber of groups into which the particles are separated. But the 
difficulty of securing a complete separation of the finer particles 
into the desired groups places a practical limit upon the number 
of groups, which is usually limited to seven.” 
»” Bricos, L. J., Martin, O. F., and Pearce, J. R., The pee Re of 
mechanical soil analysis. as. Dept. Agric., Bur. Soils, Bull. 24. 1904. 
