The daily star-mirror. (Moscow, Idaho) 1911-1939, 1922-08-16
MAKE EXPERIMENTS
ON 0NS0ILPR0DUCTI0N
UNIVERSIT MEN DETERMINE EFF.
Feet OF FORESTS ON
CROPS

In an article recently printed in the
April issue of "Soil Science" entitled
the Effect of Tree Products on the
archaeological Activities in SoiI,"
Professor w. NJ Gibbs, bacteriologist
at the University of Idaho, and c. H.
Workman, formerly associated with
Professor Gibbs, relate the results of
some interesting experiments upon
the relative infertility of forest soils
newly converted to agricultural pur-
poses.
The experiments were made to de-
termine the effect of the debris ac-
cumulating from forest gypwths of the
north Idaho timbered sections upon
the immediate productivity of the
soil. The general aim was to determ-
inc the elements that generally nee
essitate the cultivation of timber land
for five to seven years bef IRE the
yield of the various crops are up to
what they should be on the Helmer
silt loan areas, as the soil making
up the timber land is termed.
Saw dusts from the various confer
ious and decidious trees comprising
the timber sections of the north state
regions such as cedar, red fir, white
fir, larch, and whitAand yellow pine,
along with maple and ash, other tree
products such as leaves, needles and
cones, and ferns were used in max
ing the experiment to test out their
effect upon the ammonia and nitrate
accumulations in soils.
Three types of soil were used: tim
Der soil of low fertility, field soil of
medium fertility, and garden soil of
excellent fertility. Separate expert
ments were performed so, as to find
out the effect of various tree products,
the debris, and ferns upon the soils
which they are wont to cover in the
forest areas.
In the tests performed to determine
the effects of these various substances
upon the ammonia accumulation, it
was found that cedar, maple and
larch were the most toxic to the tim
ber soil in the order named Among
the substances tested other than saw
dust, cedar needles were the most
injurious, followed by yellow pine,
white pine and white fir needles. In
the tests on field soils the results
We're similar.
With regard to the MULTIPLICATION of
ammonium in soils it was also found
that the residue materials from the
forests that cover the timber soils
were quite detrimental to the biolog-
ica1 processes of the soils which are
necessary to plant growth.
The slowness with which residue
materials that carpet the timbered
area disintegrate and decompose is
found to be an important factor in
growth of normal crops on
the cut over acreages for five or six
years. 1t slows the biological process
es in the soil and prohibits the prop
er ammoniafication and nitrificatiOn
so essential to all crops.
The experiments show that the re-
duction of nitrate formation is due to
the fact that ntrifying organisms are
inhibited by the forestry materials.
When the lands have been cultivat-
ed and have grown crops for five years
the processes of disintegration of the
residue accumulated on the forest
floors have been completed and the
beneficial biologic processes of the
soil are allowed to function normally.
The experiments did not establish
any form of fertilizer to combat the
injurious effect of the decomposing
forest matter in soils, but it disclosed
the cause of delayed normal yields on
forest acreages and brought out the
harmful results of placing any such
debris on any land used for growing
crops.