The Wilmington morning star., 1940-08-19
LegumeS Grown On Land And
Removed For Hay Not Soil
Improvement Crops
GUY A. CARDWELL
General Agricultural Agent
Atlantic Coast Line Railroad
COmnanV

company
In the interest Of better soils.
which are fundamental to success
full farming, I have sought and OBJ
tanned permission to publish the fol
lowing article prepared by Prof.
c. B. Williamc, North Carolina Col
lege of Agriculture, and published
in June-July issue of Better Crops
with Plant Food" an American
Potash Institute publication:
When crops are grown on any
land and after their growth they
leave the land more productive for
crops which follow, they are term
ed soil improving. If the only limit
ing factor of a piece c.. land is
poor physical condition of the soil,
the growth on it of non-leguminous
crops like rye, oats, and millet,
and turning these under after
growth, should aid in remedying
this defe ct and thereby materially
improve the productiveness of the
oil. On t e other hand. if the trou-
BILE with the soil is lack of suffi-
Gent quantities of any one of the
essential constituents in available
forms, ike nitrogen, phosphoric
acid, potash. lime, and magnesia,
no reasonable amount of turning
under of non-leguminous crops will
likely make the soil a productive
one.
In the former case. the only fac
tor which was needed to be i'm
proved was the unfavorable physi-
cal condition of the soil which could
probably be accomplished by the
Incorporation of organic matter,
bu: in the latter case n or more
essential available plant nutrients
were present in too small quanti-
ties in the soil to permit the nor
nal G: owth of crops with economic
yields. In his latter instance no
amount of purely organic matter
added would correct the defect. 1t
could only be remedied by tn e
addition of the lacking constituent
or constituents in available form to
meet ~1equately the requirements
of the grown crops.
The only class of crops t a t
when turned under can gather and
store \ the soil any extra essential
constituents needed in crop growth
are the legumes, like soy beans,
cowpeas, clovers, lespedeza, etc,
when inoculated. The only consti-
tuent they can add 10 the soil when
pl- wed in, other than what they
These will not add any more nitro
gen to the soil than they removed
from it.
Legumes Remove Plant Food
This being the case, legumes
grown on land and removed for
hay or any other purpose a hard
ly be classed as soil-improving
crops, since under a system of
management, the nitrogen supply
of the soil will just about be main
tanned and there will be a
loss of from 8 to 16 pounds of phos-
phoric acid and 26 to 81 pounds of
potash from the available supplies
of the soil tor each ton G legume
hay removed. To replace these two
constituents in the soil and make
them the same as they were at
the beginning of the year, it would
rec uire the addition to the soil of
from so to 100 pounds Of is per
cent superphosphate and So to 1903
pounds of so per cent muriate of
potash for each ton of legume hay
removed.
It may be surprising to some
growers to know that, generally,
legumes grown and removed from
the land r much more exhaustive
upon the available phosphoric acid
and potash reserves of a soil per
hundred pounds of crop removed
than are most other crops grown
and removed. For instance. 100
pounds of soybea seed removed
from the soil carries 3.07 and 5.33
times more respectively Of these