SOME FURTHER EXPERIMENTS WITH POTATOS. 



83 



SOME FURTHER EXPERIMENTS WITH POTATOS. 



By J. Wilson and F. J. Chittenden, F.L.S., V.M.H. 



I. — Effect of Spacing on Yield. 



In Vol. 43, p. 127 of this Journal we published an account of an 

 endeavour made at Wisley in 1917 to ascertain the effect of allowing 

 greater or less space for the development of the individual potato 

 plant whether in the rows or between the rows. The conclusions drawn 

 were " that, within the limits of spacing used " in the series then 

 reported upon : 



" 1. The greater the space given to the individual plant the greater 

 the yield of that individual is likely to be. 



"2. The greater the number of plants on a given area the greater 

 the yield from that area will be." 



There were nine different spacings in the series in 1917, viz. 2 feet, 

 2 feet 6 inches, and 3 feet between the rows, and 12 inches, 15 inches, 

 and 18 inches between the plants. 



A somewhat similar series was laid down in 1918, but extended in 

 both directions, i.e., in addition to the spacing given in 1917, both closer 

 and wider spacing were given. The series was 18 inches, 24 inches, 30 

 inches, and 36 inches between the rows, and for each different distance 

 9 inches, 12 inches, 15 inches, and 18 inches between the plants in the 

 rows. There were thus 16 different spacings instead of 9 as in 1917, 

 there was in addition a plot of nine rows of potatos planted three feet 

 apart each way. 



Each different spacing occupied a plot 15 feet long and just wide 

 enough to accommodate four rows. The plots of the different spacings 

 were thus of equal length but of varying width. The different plots 

 were outlined by the variety ' Factor/ planted so that the rows of 

 ' Arran Chief ' with which the experiment was conducted each had its 

 proper space on each side of it, the spaces on both sides of any row of 

 ' Arran Chief ' being the same on each plot. The arrangement also 

 insured that the end plants of each row had the same space on each 

 side of them as the middle plants. We have drawn attention in another 

 place (see p. 74) to the importance of ensuring that all the plants in 

 any one plot in an experimental planting have precisely the same 

 spacing, and this was arranged for in this series. The plan (fig. 23) 

 shows the arrangement of the plants in one-third of the experiment, 

 the 1 Factors ' being shown in red, the ' Arran Chiefs ' in black. 



Each spacing was repeated three times in different parts of the 

 ground, in order to minimize the influence of differences in soil which 



