124 
Under such circumstances it is not surprising that the development 
of the crop of grain keeps pace with the increase of the available 
water, at least up to the point where the quantity of water is suffi- 
cient to give a maximum crop. 
The supply of water has an influence not merely on the quantity 
of the crop, but also on the rapidity of the development of the plant. 
Wollny (1881) shows that in general the grain ripens sooner as the 
quantity of water diminishes. This is well seen in the following series 
of experiments (Table 62) on the time of ripening of grain in fields 
that are sown more or less thickly. The thickly sown fields correspond, 
of course, to a less quantity of water available for each plant. 
WINTER RYE (WOLLNY, 1875-76). 
‘Number 
Number] of 
of plants| square | Date of 
to the | centi- | ripening 
square | meters (1876). 
meter. to each 
| plant. 
625 | 16 | July 18 
400 25 July 21 
229 44 July 28 
100 100 July 30 | 
25 | 400 Aug. 8 
PEAS (WOLLNY, 1877). 
| Number | 
| Number | of - 
of plants) square Date of 
to the centi- ripening | 
square meters (1877). 
meter. to each 
| plant. | 
| 
——— 22 £ 
357 28 Aug. 15 
157 64 | Aug. 17 
| 
89 118 Aug. 19 
85 7 Aug. 26 
40 254 Aug. 28 
29 | 346 Sept. 5 
POTATOES. 
Similar experiments were made by Wollny on the Ramersdorfer 
variety of potatoes. A plat containing 1 plant to 4,435 square centi- 
meters ripened by the end of September (1875), but a plat containing 
1 plant to 812 square centimeters ripened the Ist of August, and 
other plats containing 1 plant to 2,500, 1,600, 1,109 square centimeters, 
respectively, ripened at dates proportional to the area occupied 
by each plant. As edch plat received the same amount of sunshine 
and of water, the dates of ripening must have been hastened in pro- 
portion as the number of plants in each plat were increased. 
ere 
EE ————— ee 
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