11)22.] 



Trials of Potatoes, 1921. 



163 



THE MINISTRY'S TRIALS OF 

 VARIETIES OF POTATOES, 1921. 



The importance of the potato crop in the scheme of farming 

 operations is demonstrated by the fact that in 1921 nearly 

 558.000 acres were planted in England and Wales, from which 

 the yield was estimated to be nearly three million tons. The cost 

 of production, for various reasons, is high, and in order that 

 growers may be in a position to obtain the best return for their 

 outlay the Ministry, with the co-operation of County Education 

 Committees, has instituted a series of annual trials at numerous 

 centres throughout the country with the object of providing in- 

 formation as to the most profitable varieties. 



A report on the trials carried out in 1920 appeared in the issue 

 of the Journal for June last, and the results of those conducted 

 in 1921 are given in this article. 



Effect of Dry Weather. — The dry summer of 1921 to some 

 extent impaired the value of the trials. On some porous soils 

 the ripening process was so rapid that the haulm died away 

 prematurely leaving a very small crop of undersized tubers in 

 the soil. In other cases where the haulm was able to obtain even 

 a meagre supply of moisture, it remained green although very 

 little actual growth took place either at the roots or above 

 ground. With the advent of heavier rainfall, " second 

 growth " and " growing out " set in. The latter 

 occurred mainly in the South, South-Eastem and South- 

 Western Counties and may briefly be described as the 

 result of the first crop of undersized tubers producing tendrils 

 from which a second crop was obtained later in the summer. 

 This latter crop was in many cases considerably heavier than the 

 original. In the Midlands, North and extreme West, where 

 rain came earlier and in greater abundance, the original tubers 

 became enlarged producing what is usually termed " second 

 growth." 



Where the crop ripened prematurely it was abnormally light, 

 but where ripening was deferred and both crops were harvested 

 together, almost average weights per acre were obtained. The 

 proportion of seed to ware was, however, everywhere very high. 

 In some crops few ware-sized tubers were found. 



Another characteristic of the 1921 crop was the tendency of 

 all varieties of oval or kidney shape to produce an abnormal 

 percentage of round tubers. 



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