EXPERIMENTS IN CULTIVATION OF POTATOS I23 
EXPERIMENTS IN CULTIVATION OF POTATOS. 
In addition to numerous variety trials of Potatos at Wisley during 
1917, several series of experiments designed to ascertain the effects 
upon the yield of different methods of treating seed tubers were carried 
out. 
These experiments dealt with : 
I. The cutting of seed tubers (see below). 
II. The effect of various dressings on the cut surface of 
these tubers (p. 125). 
III. Greened and not-greened seed tubers with different 
numbers of sprouts v. tubers taken straight from 
the clamp (p. 125). 
IV. Planting tubers of different sizes (p. 126). 
V. The effect of planting at different distances apart (p. 127). 
VI. The effect of date of planting (p. 128). 
In every case precautions were taken to obviate as far as possible 
errors due to differences in soil. This was usually done by repeating 
the treatment on two or three plots. Care was also taken that every 
group of plants had similar exposure to that with which it was to be 
compared, and in other ways to make the comparison between the plots 
as fair as it could possibly be. 
The results are set out below : 
I. The Effect of Cutting Seed TuberSc 
The variety used in this experiment was 1 Factor.' The seed 
was grown at Wisley (third year) and was planted in mid-April, the 
rows being 27 in. apart, and the plants 18 in. apart in the rows. The 
plants were arranged in blocks of four rows of five plants, four blocks 
running across one of the garden plots. Twenty plants were grown 
under each treatment. The different treatments and the yields are 
shown in the table (p. 124). 
Taking the first eight groups first, it is evident that cutting the 
tubers tends to reduce the total crop, for No. 1 gave a greater yield 
than any of the others, while No. 2, where only the extreme heel end 
of the tuber was sliced away, was slightly less. [There is a prevalent 
idea that unless the seed tuber " decays " the resulting crop is sure 
to be small, and this is generally true, but the cutting away of the 
basal part of the seed tuber is often stated to be an aid to the requisite 
" decay." Such cutting, however, has no influence in rendering the 
contents of the seed tuber available for the sprouts. In this series 
