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SCIENTIFIC SUMMARY. 
AGRICULTURE. 
Effect of Phosphate and Potass Manure on the Cultivation of the Potato. 
• — Baron Liebig recently delivered a discourse before the Munich Academy 
of Sciences, on the subject of the cultivation of the potato crop. He 
alluded more especially to the experiments relative to the laws of the 
nutrition of plants 'which have been made under the auspices of the Insti- 
tute of Physiology, by Professor Noegeli and Dr. Zoeller. These experi- 
ments were thus carried out : Three fields were selected ; in the first the 
soil consisted of plain powdered turf of Kolb ; in the second, formed of the 
same soil, the ground was manured with ammoniacal salts, while the third 
whose soil was the same as that of the other two, was manured with the 
fixed elements, which constituted the ash of the tuber. An equal number 
of tubers was planted in each of the three fields. The field manured with 
ammoniacal salts produced more than the first, but the third, which had 
received phosphate of lime and potash, was the most fertile of the three. 
The results being represented by figures stood thus : — 
1st Field 100 
2nd do 120 
3rd do 285 
From these results it follows that the farmer may avoid the carriage of 
large masses of animal manure to his potato fields, by supplying a judicious 
mixture of phosphate of lime, gypsum, and wood-ashes. The different 
results of the three experiments can alone be attributed to the different 
compositions of the three soils, all other conditions having been identical. 
In the two first cases, there were absent those conditions necessary to pro- 
duce in the subterraneous parts as many organic substances (tubers) as in 
the third ; or in other words, to draw them from the atmosphere. Baron 
Liebig observes that these indications are not the most important results of 
the experiments alluded to. It was also found that all the potatoes drawn 
from those fields which did not possess the mineral ingredients in sufficient 
quantity, were attacked by the disease ; and, after a few weeks, the decom- 
position had extended to the interior of the tubers. On the other hand, 
the tubers grown in the third field which had been manured with the 
mineral elements of the plant remained perfectly healthy, and none of 
them exhibited the slightest trace of the attacks of oidium. It is therefore 
unquestionable that the conditions favourable to the normal development 
of plants are also those which tend to prevent disease, and that the first 
cause of the disastrous epidemic should be sought in the soil. If the latter 
