10 Xov.. ]i»n 



Coiiijwsilion of the I'oldto Plant. 



643 



done on the :^t)tli ^Mairh, after a periud of 31 days from previous 

 harvest, aud the fourth and final harvest took place on the 30th April, 

 35 days subsequent to the third. The total period of maturation for the 

 fully-developed phmts was 124 days — rouffJily, four months. .\t each 

 harvest considerable care was taken lo collect the conii)letc plant, haulms, 

 roots, and tubers, the soil being carefully sifted and hand ]iickc(l. 



In the case of the roots at the fourth harvest, .some difficulty was 

 experienced in recovering all of these, on account of their having become 

 dry and brittle, but it is estimated that the loss sustained hei's would not 

 amount to more than 30 per cent. 



At the fir.st three harvests complete recovery was made possible owing 

 to the sandy character of the soil, and the fact that at those stages the 

 roots were alive and tough. Cropping, harvesting, and analysis was done 

 in duplicate in each case, in order to reduce, as much as possible, the 

 margin of error. 



An exceptionally heavy crop was obtained in the case of the plants 

 which were allowed to mature, the tubers being of perfect shape and 

 very fine quality. 



General. 



Remarkably even results were obtained, in duplicate, from each suc- 

 cessive harvest. 



The results obtained, which are set forth in the succeeding pages, are 

 of considerable value in showing how the plant feeds, the outstanding 

 feature being the evidence, as proven by analysis, of the necessity for 

 an abundance of available food being placed at the disposal of the plant 

 from the earliest period of growth, if heavy yields are to be secured. 

 It was hoped that, as the result of this experiment, some light might be 

 thrown on the reason for immature seed being more productive than ripe 

 seed for the potato crop. 



N"o explanation of this can, however, be constructed from the results 

 obtained, as the composition of the tubers at the first, second, third, and 

 fourth harvests is sho\\ai to be practicallj' the same in plant food ratio. 

 It is remarkable that up to the present time no scientific explanation 

 can be produced relative to the phenomenal super efficiency of immature 

 seed, although tests out of number have proven the fact. 



RESULTS. 

 Total Dry Matter in the Plant. 



Table I. 

 Yield per Plant at Various Stages of Growth. 



1 2 



