EFFECT OF SOIL FACTORS OX WATEE REQUIREMENT. 
35 
T\ble XXV. — Effect of fertilizer on the water r equire m ent of potatoes and com. according 
to King 1894. 1895 , 
Pot 
No. 
Crop. 
:-' Ker. 
Dry 
matter. 
Tubers. 1 Water. 
Water requirement 
Dry Weight of 
matter. tubers. 
1 
9 
IPotatoes 3 
KN<H 
Grams. Grams. 
f 151.4 75.5 
227.1 99. 1 
1 204.3 97.2 
Kilos. 
109.2 
105. 6 
1,176 
1,102 
3 
517 1,086 
3S±23 1, 121 ±21 
112.2 
104.4 
4 
5 
6 
^Potatoes : 
Mean 
Corn* 
f 227.7 
None \ 163.1 
1 24*. 1 
Ma — d { Si 
107.5 
112. S 
472 9 " a 
1,117 
i - ' 1 "'-- * 
142.7 
106.5 
223 
2 
257 
.- - ' - 
Corn '■ 
143. 5 
n 4 
Not manured 
- _ 
232 
I 
i U* 

3Q0-Q1 
i From King"? data (1896, p. - 
J King (1895, pp. 242. 243 . The variety used was Alexander's Prolific. 
' King gives 497 for this ratio, which is evidently an error. 
* King (1894, p. 157). A flint variety was used*. The amount of manure used is not stated. It is de- 
scribed as "a dressing," placed 5 inches below the surface. 
* King gives 223 for this value, which from his data is evidently an error: the ratio was apparently taken 
in inverse order. 
LIEBSCHER*5 EXPERIMENT-. 
Liebseher (1895) measured the water requirement of oats as 
affected by different fertilizers. The pots, which were open and con- 
tained from 9 to 11 kilogTams of soil, were equipped with Liebscher's 
air-circulation apparatus (1895, p. 144). This consists of a half 
cylinder of zinc located at the bottom of the pot. with the opening on 
the under side. A zinc tube 1 centimeter in diameter is soldered to 
each end of the half cylinder and rises upward along the inner wall of 
the pot. One tube ends at the top of the pot; the other rises 15 
centimeters above the upper edge. The pot is so oriented that the 
longer tube is on the south side, where it becomes strongly heated in 
the sun, and thus induces an air circulation through the half cylinder 
below. No statement could be found regarding the method of pro- 
tecting the pots from rain, or as to whether the water was added 
through the ventilating apparatus or to the surface soil. The results 
are given in Table XXYI. These results are as a whole consistent 
and conclusive. The check series, both with clay and sand, gave a 
higher water requirement than any other series, while the complete 
fertilizer (KXP) gave the lowest water requirement. Phosphorus 
alone gave better results in the clay than in sand, while potassium 
gave a higher requirement than either nitrogen or phosphorus used 
28S 
