No. 4.] FIELD CROPS. 315 



FIELD CEOPS. 



BY PROF. WJI. P. BROOKS OF AMHERST. 



The subject as assigned me by the Board may be made to 

 include a far greater number of crops than I could possibly 

 treat of, in the brief time which is available, in a manner 

 satisfactory either to myself or to you. I shall accordingly 

 confine my attention to a few of the more important, select- 

 ing hoed rather than sown crops or grasses. Those which 

 I have chosen to speak of are corn, mangels, Swedes and 

 potatoes. 



We shall do best to consider these crops for the most part 

 separately, as I shall not attempt to deal with the many 

 questions connected with rotation. 



Some consideration of their relative capacities for food 

 production will, however, be of interest. It may be thought 

 that such comparison between the potato and the other crops 

 can have little interest, since this is used almost entirely as 

 human food, while the others are animal foods. I believe, 

 however, that it will he instructive. 



In making this comparison, I assume the yield of the corn 

 to be at the rate of 16 tons of silage per acre, which is 

 about our average; at Amherst ; for the mangels I take the 

 yield at 26 tons per acre, our average for five years ; for the 

 Swede, 19 tons, our average for three years; and for the 

 potato, 800 bushels, which is a little, above our average, hut 

 will generally be a possible amount. 



The figures which I have taken as representing the cost 

 cover one-half the manure and three-fourths of the fertilizer 

 applied and all the labor in each ease, and in round numbers 

 show the result of recent work on the Agricultural College 

 farm. These figures are : for corn, $33 per acre ; for man- 

 gels, $75 ; for Swedes, $32 ; and for potatoes, 



