328 FIELD AND GARDEN PRODUCTS 



bushels. In 18 experiments with many varieties the average amount 

 of seed cut to single eyes was at these distances 6.3 bushels per acre, 

 the usual range being from 5 to 7 bushels, though the varieties with 

 large tubers bearing few eyes required considerably more seed. 



Size of Seed Pieces. In the size of the seed piece planted the 

 practice of different farmers varies widely, some advocating a liberal 

 use of seed and others claiming equally good results from small cut- 

 tings. To aid in settling this question the State agricultural experi- 

 ment stations have made numerous tests of seed pieces of different 

 sizes. Taken separately these' experiments show certain amount of 

 divergence in results, as might naturally be expected of tests con- 

 ducted under widely different conditions. However, the majority of 

 these tests, and especially the figures expressing the average results of 

 all available American experiments, may be safely taken as indica- 

 tions of what the farmer, under ordinary conditions, will generally, 

 but not always obtain. The effect o/ size of seed pieces on yield of 

 crop will be treated here under three distinct heads: (1) On the 

 total yield; (2) on the gross yield of salable potatoes, and (3) on the 

 net yield of salable potatoes, i. e., after deducting the amount of seed 

 planted. 



Effect on Total Yield. In making up the averages below it was 

 found practicable to use the results of 19 tests of single eyes v. 2-eye 

 pieces, 4 tests of 2-eye cuttings v. quarters, 17 comparisons of quarters 

 and halves, and 44 tests of halves v. whole potatoes. The results of 

 other experiments less completely reported were used for the purpose 

 of corroboration. The following table shows the average results of 

 these tests, including potatoes of all sizes : 



Bushels. Per cent. 

 Excess from use of 



2-eye pieces over 1-eye pieces 26 



Quarters over 2-eye pieces 15 16 



Halves over quarters 24 



Whole tubers over halves 31 18 



If there are compared all the total yields with the total yield 

 produced by single eyes there appears an increase of 21 per cent 

 for 2-eye pieces, 41 per cent for quarters, 67 per cent for halves, and 

 96 per cent for entire tubers. The total yield resulting from planting 

 whole potatoes is practically double that obtained by planting single 

 eyes. Thus far there is considered only the total yield, i. e., large 

 and small potatoes, and it is found that the total yield increases 

 somewhat uniformly as the size of the seed piece is increased. The 

 farmer and gardener, however, have to consider other factors than the 

 total yield, for a heavy crop may consist very largely of tubers too 

 small for the market, or the great expenditures for seed when large 

 pieces are planted may more than counterbalance the increased yield. 

 Before noting the gross and net yields of large or salable tubers, 

 resulting from seed pieces of different sizes, it is well to consider the 

 causes inducing a somewhat regular increase in total yield accom- 

 panying the use of larger seed pieces. 



Several causes operate to increase the yield when large seed 



