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XXIII. — Nitrification of the Soil. Communication from M. P. 
BoRTiER, of Britannia Farm, Ghistelles, near Ostencl, Member 
of tlio Royal Agricultural Society of England. 
The necessity of the presence of calcareous substances in land 
lias long been admitted by agriculturists ; hence the custom of 
marling and liming has come down from very remote antiquity. 
The Greeks, the Gauls, and the Britons limed the land which 
they cultivated. Varro says that on visiting Germany he saw 
the labourers on the banks of the Rhine fertilising their land with 
white marl. 
The celebrated Bernard Palissy, remarkable for his genius and 
misfortunes, highly recommended the use of calcareous manures. 
The experience thus acquired by time has not been thrown away ; 
Puvis, in his Treatise on Manures, mentions the excellent results 
obtained by the agriculturists of the " Departement du Nord," who 
have followed this custom for centuries. 
For a long time, however, the real action of this mineral on 
the soil was but imperfectly understood, and the explanations 
which science furnished were at first but incomplete. The 
analyses of Berthier and Saussure, of Sprengcl, Way, Payen, 
Nesbit, Liebig, Johnstone, and others, showed that the pre- 
.sence of calcareous substances was essential for plants, because 
those substances enter largely into their composition. Thus 
10,000 lbs. of raw hemp take from the soil 882 lbs. of this 
matter, 8000 lbs. of dried clover absorb 152 lbs., and 5000 lbs. of 
wheat consume 34 lbs. It was therefore scientifically demon- 
strated that vegetation could no more dispense with lime than 
with nitrogen. This lime must, therefore, be furnished either by 
the soil or by manure, otherwise the crops are stunted, although 
there be an abundant supply of all the other elements. 
Besides the above-mentioned fact, established by science, there 
is another which the Abbe Rozier, the great admirer of Arthur 
Young, has- well explained, viz., the nitrification of the soil under 
the influence of this alkali : " Stratifj'ing the dunghill with lime," 
says the Abbe, " decomposes the air contained in the manure 
and converts it into nitre, which gives to the soil an extraordinary 
fertility." * 
In 1749 Piertsch, in a short treatise addressed to the Academy 
of Sciences at Berlin, which received their approval, states the 
circumstances which he thinks most favourable to nitrification. 
They may be summed up under four heads: — 1st. The presence 
of calcareous matter ; 2nd. Considerable porosity of the earth to 
* Ivozier, 'Course of Agriculture,' 1785. 
