Shoshone journal. [volume] (Shoshone, Idaho) 1884-1931, 1923-01-05
MATURING PRACTICE
GOOD FOR POTATOES
B, Geo. Stewart, In Charge Of FleIS
Crops, Experiment Station,
Utah Agricultural College.

.
ably. In the East commercial fert
llzers are in general use, especiall
In the trucking sections. Phosphorus
potash, and nitn1gen are frequentl,
applied. This form of manuring hu.
NOS yet become general in the West
Potato growers of Utah and adjacent
states depend on farm manure, and
sod-matter and for the fertllizins
elements. Occasionally late fall OF
early spring growth of alfalfa Is
turned under, but the usual practice
Is to make hay OF this and return
| to the land the manure made by the
animals to which the hay is fed.
With 30 many cattle on the summer
ranges this is probably the most prof
table system Of fertilizing the land.
The functions Of organic matter of
farm manure and sod is principally to
supply organic matter In the end,
O nplete decomposition results and
the fertilzing elements are added to
the soil in readily available form.
Important, however, as the fertilizing
elements may be, the indirect effect
is still more important Coarse man.
ure and large roots are hindrances to
cultivation and irrigation, but under |
favorable conditions, these are soon |
reduced to fine particles which are |
still undergoing active decay and
which mix readily with the soil par
tcles. Organic matter in such con-
ditlon is valuable in two distinct
ways; (1) by increasing the water
holding capacity, and (2) by creating
condition OF medium porosity in the
,oil.
Increases water-holdlng capacity
0ecaying organic matter absorbs
water much as does a sponge Be-
ause many Of the particles are hol-
ow, the surface to which films of
7ater can cling is much greater than =
n solid soil particles of the same
olume. In addition organic matter !
Intains q substance called humic n
cid which has the power of hold :.
lg many times its own weight of II
ater in loose chemical combina-
on. 81
Controls poroslty and aeration:- -
esides, organic matter loosens clay :,
lis and renders them porous. 1t has :.
g opposite effect on coarse sands -,
I'd otherwise extremely porus soils.
which it serves as sort of binder as =,
III as a retainer OF water. IA
1t Is common knowledge that wet
nd. even II nearly pure and very
'rse. will hold together with great bl'
tenacity than the same sand when
prived Of its moisture Organic re-.
tier, therefore, consolidates loose
Is both by supplying binding dit
mt and by furnishing a retainer OF 10
ter. A high degree OF looseness hit
clays and high degree of consoli- tor
ion In sands increase the water
ding powers of such soils. These ~
ditions also encourage more de- he
Ible aeration and uniformity of sue
)erature. {
ompact clays have too little pore 'i'e
ce to hold much water to permit gre
easy exchange OF gasses between hil
soil and the atmosphere. Roots ea''
bacteria both need air oxygen also
's in rendering mineral plant-foods
hle. Sandy soils are likely to De n
hot aud clayey soils too cold. The WI
a moisture and the consolidation 9th
andy soils moderate the tempera- z
of these soils and thereby de- an
ses evaporation. In heavy soils
OF pore space encourages 81
Q through ventilation. AS the wa vi
content increases to about med
the pore space increases. III
, water is added the volume de-
ses and consequently the air r.
e. 1t is at this point OF greatest tain
ma that soils aerato r,o~. ro,s,,.. dye
consequently warm up most rap cove
Roots can penetrate more easily even
more deeply because air is avail. Dla
=. xxx..- s., peri,
at sfS"'er "epels anu because mon,
is less resistance. In all re. fade,
IS the soil is then in the most wneI
able coalition for plant growth. or ;,
IFS account this condition In soil
own as the optimum (Latin word
lug the best) water content Ac. nj
decaying organic matter tends That
Ing all soils 20 this desirable put
ilon.