26 
WATER REQUIREMENT OF PLANTS. 
Table XIV. — Effect of different soils on the water requirement of wheat, according to 
Marie- Davy — Continued. 
Soil employed. 
Water re- 
Period. Dry grain, ^rement, 
■ b based on 
grain. 
1875.1 
'Feb. 1 to July 16.. ' 
1 
f 394 
372 
474 
479 
425 
262 
435 
424 
387 
379 
469 
379 
91S 
956 
728 
760 
837 
Do 
Do 
1 385 
Peat plus chemical fertilizer 
Dornecy (red) pins chemical fertilizer 
Vincennes plus chemical fertilizer 
Do 
841 
811 
894 
966 
Ivrv plus chemical fertilizer 
738 
"Do 
957 
1 1876 (p. 3S7). Conducted in open pots of 1 cubic meter capacity and 1 square meter surface, 
rection was made for evaporation. 
No cor- 
In 1875 commercial fertilizer was added to all pots. The differ- 
ences in the water requirement in the different soils were approxi- 
mately the same as during the previous year, although the water 
requirement was less for each soil than in 1874. 
LIEBSCHER S EXPERIMENTS. 
Liebscher (1895) conducted a series of fertilizer experiments in 
clay and sand soils. His results are given in Table XXVI (p. 36). 
A comparison of the results for the two soils shows a slightly higher 
water requirement in the loam than in the sand, when the whole 
series is taken into account. The same is true also of the check 
plants grown without the addition of fertilizer. 
KING'S EXPERIMENTS. 
King (1905) used four different types of soil in his water-require- 
ment investigations. Open pots 4 feet in diameter and 4 feet deep 
sunk in the ground in an open space were employed. Since the 
experiments were carried on at widely separated locations, differ- 
ences due to climatic conditions must also be recognized. The re- 
sults (Table XV) include the evaporation from the soil surface, which 
was unprotected. Direct-evaporation measurements were also made 
simultaneously in similar tanks in which no corn was grown. Taking 
the loss from direct evaporation as 100, the total loss from the soil 
tanks containing corn at the different stations in the order given in 
the table was 122, 84, 125, and 118. These ratios illustrate the 
uncertainty attending this method of measuring the water require- 
ment of crops. 
285 
