124 



EXPERIMENT STATION BECOBD. [Vol. 35 



was 



„„. used in conjunction with the 10-gm. portion of nitrate. In average yield 

 of nitrogen for all series, the yield of the third rotation stands between the 

 yields of the first and second rotations. The highest percentage of nitrogen re- 

 covered third rotation, was with nitrate of soda alone. Next in order stood the 

 cylinders on which solid and liquid manure, fresh, was used in conjunction with 

 the 10 and 5-gm. portions of nitrate of soda, respectively. Slightly more nitro- 

 gen was recovered where the 10-gm. portion of nitrate was used than where the 

 5-gra portion was used, and this is true whether the nitrate was used alone or 

 in conjunction with manure. . . . Letting 100 represent the general average 

 recovery for nitrate of soda, the recoveries for the other materials used were 

 as follows: Ammonium sulphate 65.9; dried blood 60.7; solid manure, fresh, 

 36.4; solid and liquid manure, fresh, 49.1; solid manure, leached, 39.9. and 

 solid and liquid manure, leached, 43.7. 



" In general the percentage of nitrogen in the dry matter was slightly higher 

 where manure and nitrogenous fertilizers were used together than where either 

 was used alone. Likewise there was a tendency for it to be higher with the 

 10-gm. portion of nitrate than with the 5-gm. portion. The percentage of 

 nitrogen in the dry matter was higher for the third rotation than for either the 

 first or second. 



" Lime in the form of carbonate had a pronounced beneficial effect upon the 

 yields in general. The improvement was greatest where it was used in con- 

 junction with ammonium sulphate. . . . Where manure was used with am- 

 monium sulphate, the former counteracted, in a measure, the acid tendency of 

 the latter. Lime and green manure crops, in conjunction with manure and 

 the nitrogenous fertilizers, gave the largest yields of dry matter and 

 nitrogen. . . . 



" Notwithstanding the fair applications of manure and nitrogenous fertilizers, 

 the cylinder soils have gradually lost in content of total nitrogen, though the 

 loss has been greater on some than on others. Loss of nitrogen was greater 

 with solid manure, fresh, than with solid and liquid, fresh ; it was greater with 

 the solid and liquid, leached, than with the solid, leached. The loss was almost 

 as gi'eat with 5 gm. of nitrate of soda as with 10 gm. Generally speaking, 

 the loss was greater where manure and nitrogenous fertilizers were used to- 

 gether than where either was used alone ; where ammonium sulphate and dried 

 blood were used in equivalent amounts, the loss was greater with the 

 former. . . . 



" Where the nitrogenous fertilizers were used alone there was but little re- 

 covery of nitrogen through the residual crop. Where nitrate of soda and dried 

 blood were used in conjunction with green manures, there was a fair recovery 

 of residual nitrogen, but the nitrogen thus recovered must not all be credited to 

 the fertilizing materials. Where manure was used alone, or in conjunction 

 with nitrogenous fertilizers, there was, without exception, some recovery of 

 residual nitrogen. . . . 



"It is concluded from the data here presented that the destruction of 

 nitratp.s— that is, denitrification, does not take place to any great extent in 

 geiuTal farming, under average field conditions, even when liberal amounts of 

 barnyard manure are used. 



" It is not po.ssible to maintain the nitrogen supply of the cultivated soils by 

 the use of commercial nitrogenous materials alone when used in the onlinary 

 amounts. Even with liberal applications of manure and nitrn-ennus fertilizers 

 covering a period of fifteen years, the nitrogen content of Sf.il under constant 

 cultivation was not maintained. The loss of nitrogen is attributed largelv to 

 loss through leaching." 



