144 SOILS AND FERTILIZERS 



verse condition, as excess of acids or alkalies, must 

 be corrected. Most soils contain the requisite organ- 

 isms, but frequently they are unable to do their work 

 because of unfavorable conditions, as the presence of 

 injurious matter or the lack of cultivation or food. 

 For the production of legumes, inoculation of the soil is 

 often beneficial. The commercial production and dis- 

 tribution of the organisms forming the nodules on the 

 roots of clover and other leguminous crops, and which 

 cause fixation of atmospheric nitrogen, was first pro- 

 posed and inaugurated by Nobbe. 94 The method of in- 

 oculation consists in first multiplying the organisms 

 in nutritive substances, and then sprinkling seeds with 

 the diluted solution. Inoculation with soil from a field 

 where clover or lupines have previously been grown has 

 also been successful, particularly in reclaiming sandy 

 waste lands where mineral fertilizers containing potash 

 and phosphates are used to furnish these elements, 

 while the more expensive nitrogen is acquired indirectly 

 from the air through the clover. Soils in a high state 

 of productiveness are not usually in need of inoculation 

 as they already contain all the essential soil organisms. 

 Moore's method of distributing the nitrogen-fixing organ- 

 isms of legumes in the form of cotton cultures has been 

 investigated by a number of experiment stations and 

 found inefficient. 87 



161. Loss of Nitrogen by Fallowing Rich Lands. 

 Summer fallowing creates conditions favorable to nitri- 



