Geoscience Reference
In-Depth Information
and not calculated to the production of trees only; but a red mould is very good for
other things, it is not however
.
64
This short text
contains the main indicators for soils in an agricultural context: Besides color and
depth, sweetness (that is, the absence of salt and bitterness, both indicators of soils
un
t for the production of trees
”
t for cultivation), and warmth are listed. Soil quality is seen as being dependent
on the plants to be cultivated, not just as an intrinsic quality of the soil.
Learned medieval writers read Greek, and Latin remained the language of the
learned in the western Mediterranean, it was even read by authors in Muslim Spain,
who wrote in Arabic. The agricultural knowledge of Antiquity remained available
mainly to monks, who had access to monastic libraries, but was not con
ned to
them. New soil knowledge was mainly incorporated into encyclopedias in the
Middle Ages. However, a learned North Italian citizen by the name of Petrus de
Crescentiis, or Piero de Crescenzi who had worked as legal adviser to city councils
for three decades before writing his topic, wrote an agricultural manual. His Ruralia
Commoda were
nished around 1300. They offer a full-scale treatment of all
matters rural. It enjoyed great popularity and was translated into several European
languages, among them Italian, French and Polish. It was also printed at least six
times in three languages before 1500, with a circulation of several hundred topics
for each printing. He developed soil terminology further, using 12 new adjectives
not found in the manuals of Antiquity.
Petrus de Crescentiis devotes a chapter of his second topic to the question how
the fecundity of soil can be determined. He starts with a detailed list of qualities a
good soil should not have, such as being gravelly, clayey, bitter or salty, and then
goes on to describe indicator plants such as raspberry, cane or clover, which, if they
grow of their own accord on unused land, can be taken as indicative of good soil.
The color of the soil is not of high value in determining its quality; its fatness and
sweetness are most important. The fatness can be tested by sprinkling a clod with
water and kneading it, if it gets gluey and sticky, it is fat. The sweetness can be
tested by placing a sample from the part of the
eld which looks least desirable into
fresh water and taste it.
65
With the exception of the advice that sampling should
take place at the worst looking part of the
eld, Petrus de Crescentiis offers old
wisdom here: all his tests and considerations are already described in texts from
Antiquity. But the practical advice to choose the sampling place well is a welcome
addition to knowledge. Speci
c indicator plants are also given in the topic on
viticulture (IV, 6). His treatment of soils in the general chapter is not very detailed,
but he names the suitable soil for many of the tree and herb species he lists in the
compendium.
About a century earlier, Ibn al-
laha, written in Muslim
Spain, offered a complete treatment of all aspects of agriculture. We know next to
nothing about the author, who lived probably in Seville and wrote his elaborate
'
Aww
â
m
'
s Kitab al-
64
Owen (
1806a
).
65
Petrus de (
1995
-
2000
).
