40 6 INVESTIGATION BY CULTURE EXPERIMENTS 



for its deposition and accumulation only an undisturbed lodging 

 place, and dirty snowbanks form in such places near open fields. 



NOTES ON THE ROTHAMSTED FlELD EXPERIMENTS 



The records herein given must be considered at best as summaries 

 of the Rothamsted field experiments. Aside from the experiments 

 already mentioned, beans were grown every year from 1849 to 

 1859, and oats every year (except 1877, fallow) from 1869 to 1878, 

 under different systems of fertilizing, on Geescroft field. The 

 average yield of oats for the five years (1869 to 1873) ran g e > i n 

 bushels per acre, from 19.9 (unfertilized) and 24.5 (minerals) to 

 47 (ammonium salts) and 59 (ammonium salts and minerals) ; 

 and for the other four years from 13.1 (minerals) and 13.8 (unfer- 

 tilized) to 28.9 (ammonium salts) and 38 (ammonium salts and 

 minerals). 



No oats were grown on this field from 1847 to 1868, and the first 

 crop of oats (1869) varied, in bushels per acre, from 36.6 (unfer- 

 tilized) and 45 (minerals) to 56.1 (ammonium salts) and 75.2 

 (ammonium salts and minerals). The records for the 9 years, 

 1860 to 1868, are: fallow, wheat, wheat, fallow, beans, wheat, 

 beans, wheat, wheat; with no fertilizers applied during those 

 years except farm manure for the beans in 1864. 



Experiments with legume crops, especially with beans and clover, 

 have been in progress on Geescroft or Hoos fields (or both) most of 

 the time since 1847. In summarizing their experimental results 

 after more than fifty years, Lawes and Gilbert recorded the 

 following statements (Rothamsted Memoranda, published in 

 1901) : 



"When the same description of leguminous crop is grown too frequently on 

 the same land, it seems to be peculiarly subject to disease, which no conditions 

 of manuring that we have hitherto tried seem to obviate." 



"The general results of the experiments on ordinary arable land in the field 

 has been that neither organic matter rich in carbon as well as other constitu- 

 ents, nor ammonium salts, nor nitrate of soda, nor mineral constituents, nor a 

 complex mixture, supplied with manure, availed to restore the clover-yielding 

 capabilities of the land; though, where some of these were applied in large 

 quantity, and at considerable depths, the result was better than when they were 

 used in only moderate quantities, and applied only on the surface. 



