TH6 JOUHNAIa 



OF 



^fie ^Department of H^gricufture 



OF 



VICTORIA. 



Vol. XV. Part 11. 10th November, 1917. 



THE COMPOSITION OF THE POTATO PLANT AT 

 VARIOUS STAGES OF DEVELOPMENT. 



By J. T. Ramsay, Potato Expert, and \Y. C. Robertson, Supervising 



Analyst. 



Object of Experiment. 



During the past season, 1916-17, an interesting test was carried out 

 to determine, I. the rate of assimulation of food from tlie soil by the 

 potato plant, and II. the relative proportions of each of the principal 

 elements contained in the plant at various stages of its growth. 



How Conducted. 



In order to insure the best possible condition for the growth of the 

 crop, together with the maintenance of the greatest facility for the 

 harvesting of all portions of the plant, viz., haulms, tubers, and roots, 

 the crop was grown in a synthetic soil. 



This soil was constructed from Carrum sand 13 parts, clay loam sur- 

 face soil 2 parts, and well-rotted farmyard manure 1 part; the whole 

 when mixed making a choice light sandy loam of a very desirable 

 physical condition. 



To guarantee com])lete harvesting control over the wbole of the 

 portions of the plants operated upon, each seed set was planted in a hard- 

 wood box 18 inches by IS inches by 18 inches, containing 130 lbs. of soil 

 — the seed being placed at a depth of 4 inches below the surface. To 

 prevent too rapid evaporation of moisture from these boxes of soil and 

 to maintain an even temperature they were placed in a trench cut in the 

 ground, so that the tops of the boxes were practically level with the 

 surface of the land surrounding. 



Care was exercised to insure perfect drainage in order that the plants 

 might be permitted to develop evenly from start to finish of the growing 

 period. To further insure this, water, as rq,quired to keep the soil in a 



13587. 



