FIELD EXPERIMENTS INDICATING FIXATION 9 



the following comparative figures were obtained after both had 

 been under similar treatment for many years. 



TABLE III. Nitrogen in Crop and Soil. Leguminous Plants compared 

 with Wheat and Fallow. Hoos Field. 



In another experiment in Little Hoos Field, after five years' 

 cropping by cereals without any nitrogenous manure, in 1872 a 

 portion of the field in barley was sown with clover ; in 1873 

 this portion carried a clover crop which was cut three times, 

 the other portion which had not been sown with clover was 

 again cropped with barley. Determinations of the nitrogen 

 removed in 1873 showed 151 Ib. in the clover crop and 37 Ib. 

 per acre in the barley crop respectively. In the following 

 year (1874) barley was again sown over the whole area, but the 

 barley crop which followed clover took away nearly twice as 

 much nitrogen as that which followed barley, although this 

 had contained less than the corresponding clover. Yet an 

 analysis of the soil immediately after the 1873 crop had been 

 removed showed more nitrogen in the land where clover had 

 been growing than where the barley had been growing, as 

 shown in Table IV. (p. 10), where all the results are summarised. 



In yet another experiment, land which had previously 

 grown beans and then been fallow for five years was sown 

 with barley and clover in 1883, the clover being allowed to 

 stand in 1884 and 1885. At starting, the soil was analysed ; 

 the surface 9 inches contained on an average 2657 Ib. per acre 

 of nitrogen, while of nitrogen as nitric acid the soil only con- 



