Experiments on the Potato-Crop, 563 



Of the whole series of 39 experiments, 25 were in favour of 

 large sets, and 14 showed an opposite tendency ; but the pro- 

 portion borne between these numbers does not fully represent 

 the actual result, Avhich is more fairly stated by the weights of 

 the balances on either side ; for whilst the gains on the 25 (acres) 

 experiments calculated per acre amounted to 94 tons 3 cwt. 1 qr. 

 62^ lbs. in favour of large sets, the gain (14 acres) on the 14 experi- 

 ments favourable to the smaller sets amounted to only 34 tons 

 17cwt. 1 qr. 27^ lbs., leaving (after setting the gains against the 

 losses) an average net balance, on the 39 comparisons, of more than 

 1 ton 10 cwt. in favour of the larger sets on each advance, namely, 

 from 1 to 2 ozs., from 2 to 4 ozs., from 4 to 6 ozs., and from 6 to 

 8 ozs. 1 have been particular in noticing these exceptional irregu- 

 larities, and their general bearing on the tenor of the experiments, 

 as an element inseparable from agricultural experiments, and 

 as requiring the fullest recognition in the estimation of results. 



It now only remains briefly to recajntidate the general bearing 

 of the experiments, the results of which have been descj-ibed in 

 detail. 



Firstly. Every increase in the size of the set, from 1 oz. up to 

 8 ozs. in weight, produces an increase in the crop much greater 

 than the additional weight of the set planted. The net profit 

 over and above the extra weight of the sets in planting 4 oz. sets 

 in lieu of 1 oz. sets, amounted on the whole series of experiments 

 to between 3 and 4 tons per acre ; and the further profit on the 

 increase of the size of the set from 4 ozs. to 8 ozs., averaged 

 about 5 tons an acre ; all the intermediate steps partaking pro- 

 portionately of the increase. 



Secondly. The advantages in favour of the large sets is more 

 marked in the late than in the early varieties. 



Thirdly. In the use of small sets of from 1 oz. to 3 ozs. in 

 weight, a larger balance over and above the weight of the sets 

 was obtained by planting from 6 to 9 inches apart in the rows 

 than at wider intervals. 



Fourthly. Increasing the intervals at which the sets are planted, 

 even of the largest size, in the rows to more than 12 inches, 

 diminishes the crop, and the wider intervals induce no increase 

 in the weight of the produce of the individual sets. 



Fifthly. It may be broadly stated that the weight of the crop 

 is proportionate to the weight per acre of the sets, and that small 

 sets will produce the same crop as an equal weight per acre of 

 large sets. The fact is, however, of limited application, as a 

 weight of very small sets equal to a weight of full-sized potatoes 

 could not be got into the ground, except by planting them so 



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