SoME RELATIONS OF ORGANIC MATTER IN SOILS 5 
carbon and nitrogen have disappeared from the cultivated soils 
to a larger extent than from the uncultivated soils. He showed 
that the cultivated soils had lost, in round numbers, from one- 
fifth to two-fifths of the nitrogen and from one-fourth to one- 
half of the organic matter. 
Potter and Snyder (1916) stated that in a general way the 
total nitrogen determinations in their experiments showed that 
there was a smaller loss or a greater gain of nitrogen for the 
limed soils than for the corresponding unlimed soils. 
Bear (1916) indicated that quicklime reduced the amount 
of carbon and of nitrogen in the soil. 
Potter and Snyder, in a later experiment (1917), concluded 
that lime in the form of a carbonate, under the conditions of 
the experiment, appreciably enhanced the rate of decomposition 
of both original soil organic matter and the organic matter 
of stable manures, oats, and clover when added to the soil. They 
stated that two of the more important results of this were the 
increased availability of plant food and the more rapid depletion 
of the soil organic matter. They pointed cut that the latter 
effect would be partially and perhaps entirely offset by the fact 
that with lime larger crops could be grown, which would add 
more organic matter as crop residue to the soil. 
Breazeale (1917) found that calcium carbonate had a slight 
destructive action upon the organic matter of the soil. 
Jensen (1918) stated that in most cases when lime was 
added to alfalfa in basins, greater increase in the humus content 
occurred than when alfalfa alone was used. 
Christie and Martin (1918) state that it is evident from data 
considered that all soils do not react chemically with lime in 
the same manner. 
Bizzell and Lyon (1918) write: “On Volusia silt loam ad- 
dition of quicklime increased the amount of carbon dioxide in 
the soil air. This effect was noticed both on the cropped and 
uncropped tanks. On, Dunkirk clay loam quicklime apparently 
produced no effect.” 
Swanson and Latshaw (1919) say: 
In the sub-humid section the fields cropped to grain lost one-fourth of 
the nitrogen as compared with the surface soil of the native sod. The al- 
falfa fields contain 5 per cent less nitrogen than the native sod, but 20 
per cent more than the fields in grain. .... 
In the semi-arid section the cropped soil has lost one-fifth of the nitrogen 
as compared with the native sod. Alfalfa fields contained 15.7 per cent 
