191 1.] The Cultivation of the Sugar-beet. . 795 



an important place in farm economy, but the profit, if any,, 

 would be that of sugar-beet over mangolds. 



Climate. — The influence of climate is considerable, tem- 

 perature, rainfall and sunshine all having a direct effect on. 

 the successful cultivation of the crop, especially as regards 

 percentage contents of sugar. By comparisons of meteoro- 

 logical observations since 1870 M. Pagnoul has concluded 

 that the temperature in May, June, and July has a prepon- 

 derating influence on the yield of the crop, and that of 

 September a very marked effect on quality. Lawes and 

 Gilbert remarked in 1898 that "those who have thoroughly 

 studied the question of the most suitable temperature for the 

 growth of sugar-beet, come to the conclusion that a summer 

 mean temperature of not less than 70 0 F. is desirable to 

 ensure success." These writers also endeavoured to show- 

 that the mean temperature of the East and South of England- 

 is not nearly up to the 70 0 F. standard during June, July, 

 August and September, and they argued that "so far as 

 temperature is concerned, we should be at a disadvantage 

 compared with other beetroot sugar producing countries." 

 "Nevertheless," they added, "it is probable that, in the 

 majority of seasons, sugar-beet could be grown of fair quality 

 for sugar-making in the most favourable districts of the 

 country, which would be in the eastern and southern 

 counties." The results of experiment since Lawes and 

 Gilbert wrote show that a mean summer temperature of 

 70 0 F. is by no means necessary, for heavy crops containing 

 a high average percentage of sugar have in many cases been 

 grown in the eastern counties. In fact, as Petermann and 

 Pagnoul appear to have found, the quantity of organic 

 matter produced by the sugar-beet probably depends more 

 on light and rainfall than on the total heat received during 

 growth. 



The sugar-beet crop has need of considerable water, trans- 

 piration being heavy, and Hollrung states that for the growth 

 of 1 lb. of dry matter ('== about 4 lb. of the green plant), 40 

 gallons of water are necessary. As with other root crops, 

 however, prolonged rains may be harmful owing to the 

 difficulty experienced in keeping the crop clean. 



The diagram on p. 796 shows graphically the average 



