120 BOARD OF AGRICULTURE. 



than we can explain why cattle thi-ive on foods that are inuntritious 

 for man. 



Here, then, is another opportunity for experimental work, in which 

 the capacities of different crops to obtain their food from the material 

 in the soil are to be studied. The method of procedure would be 

 much the same in this case as in the preceding, except that the 

 different fertilizers should be applied in different proportions. That 

 is, the nitrogen for a corn crop, for instance, should be supplied in 

 quantities var3'ing from nothing to the full amount assimilated by 

 the desired crop during its growth, the oljject being to find how little 

 niti'ogen the crop can get along with aside from that which the soil 

 can supply. 



I mention the corn crop in this connection, because some very 

 interesting results have already' been obtained from experiments on 

 the capacity of this crop to get its nitrogen supplj' from other sources 

 than from the manures applied to the soil. Tiiese experiments were 

 investigated by Prof. W. O. Atwater, who is the pioneer in syste- 

 matic field experimenting in this country. The investigations were 

 commenced in 1877, and the results of four years' experimenting 

 have already been reported. 



Prof. Atwater's plan was to supply the mineral frrtilizers to the 

 soil in quantities sufficient to furnish these materials in a crop of 

 fifty-five or sixty bushels of corn to the acre. The nitrogen appli- 

 cations w^ere varied, giving to one plot none, to another one-third 

 ration for a full crop, or 24 pounds ; to another two-thirds ration, 

 or 48 pounds ; and to another a full ration, or 72 ponnds. 



In the report of the Connecticut Board of Agriculture for 1880, 

 are^the results of four 3-ears' experimental work on the '' Sources of 

 nitrogen supplj- " for corn, from which I eoi)y the following tables 

 in which tliese results are summed up, as an example of experimental 

 work that farmers can do, and as showing the practical benefits of 

 such work. 



Average results of experiments with corn in 1878-79-80 : 



Eleven Special Experiments gave with — 



Bushels of Shelled 

 Corn per iicre. 



Mixed minerals alone 4.5.2 



Same H- 24 pounds nitrogen 54.-5 



Same + 48 pounds nitrogen 5.5.4 



Same + 72 pounds nitrogen , 56.7 



