Decomposition of Sweet Clover as a Green Manure 127 



character of the Volusia soils, Carr (1909:11) states: " In recent years 

 extreme difficulty has been experienced in seeding clover, amounting 

 in many cases to complete failure. Corn seldom gives any yield of 

 mature grain; wheat yields have become so low that attempts to grow 

 this crop have been abandoned. ... In the region occupied by the 

 silt loam many farm homes are abandoned." Carr concludes that this 

 unproductivity is due to poor physical condition, lack of organic matter, 

 and general unfavorable conditions for the development of bacteria. 

 Hence this type of soil, because of its general distribution and run-down 

 character, is an excellent one on which to try the restorative powers of 

 sweet clover. 



The soil was obtained from the farm of Mrs. Ellen Crutts, at Varna, 

 New York, and came from a field that had recently received no application 

 of manure or commercial fertilizer. The soil contained approximately 

 35 per cent of pebbles too large to pass a half -inch mesh. A sample was 

 analyzed according to the methods described by the United States Bureau 

 of Chemistry.^ The mineral constituents were determined in the solution 

 obtained on strong acid digestion. Phosphorus was weighed as mag- 

 nesium pyrophosphate, and calcium as the oxide. Potassiimi was deter- 

 mined by the Lindo-Gladding method. The loss on ignition over a 

 Bunsen was considered volatile matter. As a measure of the organic 

 matter present, the organic carbon was detennined by combustion with 

 chromic acid, using the modification described by Cameron and Breazeale 

 (1904). The inorganic carbon was first determined and deducted from 

 the total obtained on combustion. A determination of humus was also 

 made according to the procedure described by the United States Bureau 

 of Chemistry. Di"y ammonium carbonate was added to the ammoniacal 

 solution to flocculate the clay particles before filtering. Nitrogen was 

 obtained by the Gunning method, modified to include the nitrogen of 

 nitrates, using copper wire as a catalytic agent. The nitrates were 

 determined on a dry sample by the phenol-disulfonic-acid method. Com- 

 parisons were made in the colorimeter designed by Schreiner. The 

 results obtained on analysis of the soil used in the first year's work 

 were as follows, the percentages being based on the moisture-free fine 

 soil: 



Potassium oxide o. 3683 per cent 



Calcium oxide o • 475 per cent 



Phosphorus pentoxide o. i486 per cent 



Volatile matter 6.05 per cent 



Organic carbon i . 36 per cent 



Humus 1 . 15 per cent 



Nitrogen o. 183 per cent 



Nitrates 57 parts per million 



3 Official and provisional methods of analysis, Association of Official Agricultural Chemists. Bulletin 

 107, U. S. Bureau of Chemistry. 1908. 



