48 RELATION OF LIME AND MAGNESIA TO PLANT GROWTH. 
EXPERIMENTS WITH WHEAT AND OATS. 
On July 11 the pots were planted to wheat. On July 18 the wheat 
plants had made growths as follows: 
MeO ns CaO. Growth. 
| Per cent. Per cent. Centimeters. 
| 0.1 0.8 2:5 
| 0.2 7 | Dis 
0.3 0.6 | 12 
0.4 0.5 | 18 
| 0.5 0.4 15 
| 0.6 0.3 | a) 
0.7 0.2 | 5 
0.8 wl: | 2.5 
On July 23 the growths made were comparatively as reported above 
(see Plt, figs 1): 
On August 6 the plants in one series of pots were taken up and the 
root system examined, with the following results: In pots with— 
t 
MgO. | CaO. Growth, Condition. 
| 
| Per cent. | Per cent. Centimeters. | 
Osta) 0.8 | 6 | Bushy, poorly developed. 
0.2 0.7 | 6 Bushy, poorly developed. 
0.3 0.6 16 Bushy, well developed. 
0.4 0.5 16 Bushy, well developed. 
0.5 0.4 i Poorly developed. 
0.6 0.3 3 No root hairs. 
O57 0.2 3 No root hairs. 
0.8 0.1 4 No root hairs. 
As in the growth above ground, the root systems showed the most 
favorable conditions to be present where the amount of soluble CaO 
was slightly in excess of the soluble MgO. Where the CaO was in 
great excess the root system was apparently healthy, but poorly 
developed. When the MgO was in greatest excess the root system 
showed an unhealthy condition, the absence of root hairs, and later 
the shrinkage and discoloration of the larger portion of the root. 
On August 20, forty days from the time of planting, the wheat in 
the remaining series of eight pots, with the exception of the extremes, 
had become more equal in height. The general thriftiness of the 
plants, however, appeared to range as before reported, the pots with 
lime moderately in excess of magnesia making the best growth, the 
plants in the pot with MgO 0.4 per cent and CaO 0.5 per cent being 
larger and stronger, and the thriftiness ranging from this ratio down 
to MgO 0.2 and CaO 0.7, and MgO 0.7 and CaO 0.2 per cent. In the 
two extreme pots the plants were dead. 
