88 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



CONTRIBUTIONS FROM THE WISLEY LABORATORY. 



XXV. — On the Influence of Planting-distance on the 

 Yield of Crops. 



By F. J. Chittenden, F.L.S. 



The need for allowing a sufficient space about cultivated plants to 

 permit them to develop properly is generally recognized, but the 

 extent to which yield is affected by even the normal closeness of 

 planting is, perhaps, rarely realized. The following figures, obtained 

 in two series of experiments at Wisley in 1914, illustrate this point very 

 clearly. All the figures obtained in the experiments are given ; they 

 are not selected examples, and are therefore the more convincing. 



An investigation was being carried out into the effect of certain 

 additions to the soil upon the yield of crops. The materials added 

 need not be further particularized here, as the yield from the different 

 plots is not brought into comparison, and they do not affect the 

 point under discussion. The crop grown for the experiments was 

 the turnip. 



Series I. — The first of the two series of experiments comprised 

 fifteen plots, each 33 feet long by 7 feet 6 inches broad, the plots running 

 east and west and side by side. 



Three rows of turnips were sown on each plot at the normal distance 

 of 18 inches apart. The outer row of turnips on one plot was thus 

 4 feet 6 inches from the nearest outer row of the next plot. They 

 were arranged in this manner in order to ensure that the influence of 

 the manure supplied to one plot should not be felt by the plants on 

 the next. The two outer rows on each plot had therefore a much 

 greater open space on one side of them than on the other, while the 

 middle row had plants close to it on each side. 



This series was sown on May 25, 8-5 grams of ' Early White Stone • 

 turnip being sown in each row. They were thinned on June 24, 

 and pulled, counted, and weighed on July 29, the tops and roots free 

 from soil being weighed separately. Table I. shows the average 

 weight of both top and root of the plants from each of the three rows 



