EFFECT OF SOTL FACTCTOS ON WATER REQUIREMENT. 
25 
EFFECT OF SOIL TYPE ON THE WATER REQUIREMENT. 
MARIE-DA VY's EXPERIMENTS. 
Marie-Davy reports experiments (Table XIV) which were designed 
to show the effect of different soils on the water requirement of wheat 
for grain production. In the first series (1875), 2-liter glass con- 
tainers with small necks were employed and direct evaporation 
practically elimmated. Each soil was given 10 different treatments, 
but since the different soils received the same series of treatments, a 
comparison on the basis of the soil is possible. In the later experi- 
ments (1876) large, open casks, 1 meter square, were employed. A 
single cask of soil was used in each treatment, leaf mold being added 
in varying amounts. The addition of the leaf mold does not appear 
to have had beneficial effects except in the case of soil from Saint- 
Ouen. In all other cases it increased the water requirement of 
wheat for grain production. The total dry matter is not recorded 
and no adequate description of the soils is given. The differences 
recorded are probably due partly to soil differences, although the lack 
of agreement in the two tables indicates rather high experimental 
errors. It is probable, however, that had the water requirement 
been computed on the total dry matter the results would have been 
modified. The addition of leaf mold often increases the straw as 
compared with the grain yield, and this may account for the high 
water requirement for grain when leaf mold was employed. 
Table XIV. — Effect of different soils on the water requirement of wheat, according to 
Marie- Davy. 
Soil employed. 
Montsouris plus fertilizer 
Saint-Ouen plus fertilizer 
Gravelle plus fertilizer 
Dornecy (brown) plus fertilizer. 
Ivry plus fertilizer 
Vincennes plus fertilizer 
Fontenay sand 2 plus fertilizer . . 
Montsouris plus 25 kilograms leaf mold 
Saint-Ouen plus 25 kilograms leaf mold 
Saint-Ouen plus 50 kilograms leaf mold 
Gravelle plus 25 kilograms leaf mold 
Gravelle plus 50 kilograms leaf mold 
Dornecy (brown) plus 50 kilograms leaf mold. 
Peat 
Dornecy (red) plus 50 kilograms leaf mold. 
Vincennes plus 25 kilograms leaf mold 
Vincennes plus 50 kilograms leaf mold 
Ivry plus 25 kilograms leaf mold 
Ivry plus 50 kilograms leaf mold 
Period. 
1874 i , 
1874.3 
r Feb. 1 to Julv23. 
Dry grain. 
3.99 
5.48 
5. 65 
4.13 
5.09 
6.0G 
4.20 
300 
380 
303 
256 
328 
324 
312 
308 
313 
236 
Water re- 
quirement, 
based on 
grain. 
1,126 
1.034 
1,010 
1,435 
1,056 
1,015 
1 , 364 
964 
1. 160 
913 
1.122 
1,387 
1 , 047 
1,015 
1,087 
1,163 
1.105 
1 . 576 
1 1875 (pp. 306-310). Ten pots of each soil each of 2 liters capacity and each receiving one of the fertilizers 
given in table. Evaporation from the soil practically eliminated. In Marie-Davy (1874) many of the 
data given in this table are presented in a somewhat different form. The water requirement there recorded 
is based on total water loss and total dry matter produced by all pots, while the water requirement here 
given is the mean for the series of pots. 
2 Fontenay sand received different fertilizers and only 9 pots were used. 
3 1876 ("P- 387). Conducted in open pots of 1 cubic meter capacity and 1 square meter surface. No cor- 
rection was made for evaporation. 
285 
