142 Nebraska Agricultural Exp. Station, Research Bui. 6. 
EFFECT OF INCREASING THE FERTILITY OF SOILS DIFFERING IN MOISTURE 
CONTENT. 
In 1914 (Table 56) half of the potometers in each degree of 
soil moisture received an application of 1.75 pounds of well- 
rotted moisture-free sheep manure per plant, which is at the rate 
of 9.3 tons per acre, counting 10,668 plants per acre grown three 
per hill, with hills 3.5 feet apart. The object was to note the 
effect of increasing the fertility of soils differing only in their 
water content. One frequently reads the statements that: As a 
principle in dry farming, a shortage of moisture may be offset 
by an increase in soil fertility thru manure or other fertilizer; to 
a certain extent, manure may take the place of water; and 
a field of grain may be grown with actually less rainfall if the 
soil fertility is increased, even tho the soil is fertile to begin with, 
as are most soils of the Great Plains area of the United States. 
No definite conclusions may be drawn from the single test 
reported here concerning this interrelationship, for the reason 
that the lowest relative saturation employed proved little in- 
ferior to the optimum moisture content — due to the low atmos- 
pheric evaporation values of the particular season. The applica- 
tion of the manure to the soil with a shortage of moisture in- 
creased the yield of dry matter 21 per cent, and also increased 
the total water used per plant 14 per cent and the water used 
per square inch leaf-area 24 per cent. (The increased transpira- 
tion per unit leaf-area when manure was applied was probably 
partially due to a healthier condition of the lower leaves during 
the latter half of the growing season.) The water requirement 
per unit dry matter was reduced 5 per cent. The application of 
manure affected the results in very much the same manner in 
the optimum (70 per cent) and the overabundant (95 per cent) 
soil moisture, as may be seen from a study of Table 56 for 1914. 
The plants which started out in 1914 with an optimum (70 
per cent) amount of moisture and received each day thereafter 
only two-thirds as much water as was transpired by the average 
of eight plants in soil constantly 70 per cent saturated, were 
reduced 14 per cent in yield of dry matter. With these plants, 
the manure failed to affect in a material degree any of the im- 
portant growth or transpiration relationships, as is summarized 
in Table 56. Other data indicate that probably different results 
would be secured under such conditions as prevailed in 1913, 
when moisture was a great limiting factor with those plants in 
the lowest saturation. This problem of the effect of increasing 
the fertility where a marked shortage of moisture exists will be 
further investigated in future experiments. 
