EXPERIMENT STATION BULLETINS. 355 



or the straw retiirued after threshing the loss would be diminished by 

 approximately 750 pounds of nitrogen, 82 pounds of phosphorus and 

 5G0 pounds of potassium. 



On the sandy farm the losses are not so heavy because the crops pro- 

 duced are not so large. 



Table 5. — Plant food balance on a 100-acre general farm, growing 25 acres of clover, and carrying 



6 cows, 4 young cattle, 5 horses and 14 hogs. 



Nitrogen- 

 pounds. 



Phosphoric 



acid — 



pounds. 



Potash- 

 pounds. 



Plant food in feed consumed and pasture grass 



Loss during digestion and handling of ma- [ Maximum. . . 

 nure ] Minimum . . . 



[ Average 



Returned to soil in bedding, stover, etc 



[ Maximum. . . 

 Total returned to soil ] Minimum.. . . 



[Average 



Removed from soil in crops 



f Maximum. . . 

 Annual loss from soil ] Minimum . . . 



[ Average 



2,641.61 

 1 , 544 . 44 

 1,065.18 

 1,304.81 

 268.22 

 1,844.65 

 1 , 365 . 39 

 1 , 605 . 02 

 3,998.73 

 2 , 633 . 34 

 2,1.54.08 

 2,393.71 



829.22 



468 . 25 



303.61 



385 . 93 



70.71 



595.29 



431.65 



512.97 



,901.63 



,469.98 



,306.34 



1,388.66 



2 , 053 . 24 



905 . 33 



676.13 



790.73 



440.64 



1,817.75 



1,588.55 



1,703.15 



4,790.26 



3,201.71 



2,972.51 



3,087.11 



Table 6.-7-Plant food balance on a 100-acre general farm on sandy soil with a sliort rotation, in- 

 cluding 25 acres of clover, and carrying 6 cows, 4 young cattle, 5 horses and 14 hogs. 



Nitrogen- 

 pounds. 



Phosphoric 



acid — 



pounds. 



Potash — 

 pounds. 



Plant food in fee<l consumed and pasture grass 



Lo.ss during digestion and liandling of ma- [Maximum. . . 

 nure I Minimum.. . . 



[ Average 



Returned to soil in bedding, stover, etc 



f Maximum . . . 

 Total returned to soil I Minimum. . . 



[ Average 



Removed from soil in crops 



f Maximum . . . 

 Annual loss from soil ' Minimum.. . 



[ Average 



2,701.97 

 1 , 583 . 98 

 1,097.13 

 1,340.54 

 170.00 

 1,774.84 

 1,287.99 

 1,531.43 

 2,949.27 

 1,661.28 

 1,174.43 

 1,417.84 



828.08 



458 . 25 



303.56 



379.53 



78.00 



602 . 52 



447 . 80 



526 . 55 



1,468.88 



1,021.08 



866.36 



942.33 



2 , 082 . 34 



1,015.28 



669.40 



803 . 04 



211.00 



1,623.94 



1,278.06 



1,490.30 



3 , 625 . 90 



2 , 347 . 84 



2,001.96 



2,135.60 



It is impossible to state the actual loss of nitrogen per year on any 

 farm, because there are several variables such as the fixation of nitrogen 

 and the losses due to leaching, erosion, etc. The fact that some soils 

 are growing lighter in color, however, is evidence that a considerable 

 loss of nitrogen is sustained. This is borne out by the results of field 

 experiments quoted later in this publication which show a decided and 

 profitable increase in the yield of wheat on the sandier soils as a result 

 of the use of commercial nitrogen. 



A consideration of these farming systems leads to the inevitable con- 

 clusion that the fertility of the soil can not be maintained without the 

 supplying of plant-food elements from some exterior source. The source 

 at present available is commercial fertilizers. 



THE USE OF FERTILIZERS. 



Most farm practices reduce to a greater or less extent soil fertility. 

 In fact it is common knowledge that fertile, virgin soils produce an 



