ROOT-CROPS. 



47 



the result, it may at any rate be stated as a matter of fact 

 that nitrogenous manures greatly increase the general vege- 

 tative activity of such plants, and consequently, if the other 

 necessary supplies are not wanting, the activity of the 

 formation of their natural or characteristic products is 

 enhanced. 



It has been seen that the supply of potash as well as of Potash and 

 nitrogen has much to do with the amount of root-develop- y s ^ r ^ 

 ment, and the amount of sugar produced. The following 

 table shows the amounts of sugar for 1 of potash, in the 

 roots. The supply of potash was the same in all cases ; in 

 Series 1 without any nitrogenous manure, but in the other 

 series the nitrogenous manures as indicated, in each of the 

 first three years. The results are the means of plots 6 and 

 4, over the three years with the direct supply of nitrogen, 

 over the two years without further nitrogenous supply, and 

 over the five years, three with and two without, nitrogenous 

 manure on Series 2, 3, 4, and 5. 



SUGAR FOR 1 OF POTASH IN THE ROOTS. 



3 years, 1871-73 

 2 years, 1874-75 

 5 years, 1871-75 



Series 1. 



Without 



nitrogenous 



manure. 



47.9 

 43.4 

 46.1 



Series 2. 



With 

 sodium 

 nitrate 



39.6 

 35.5 

 38.6 



Series 3. 

 With 

 ammonium- 

 salts. 



38.9 

 38.7 

 38.9 



Series 4. 



With 

 rape-cake 



and 

 ammonium- 

 salts. 



34.1 

 37.6 

 34.9 



Series 5. 



With 



rape-cake. 



42.0 

 39.1 

 41.3 



In the first place, it is to be observed that the amount of 

 sugar for 1 of potash in the roots is considerably the greater 

 where no nitrogen was supplied by manure, and where 

 there was no luxuriance, and by far the ripest roots ; con- 

 ditions under which the sugar produced would presumably 

 be the maximum for the amount of nitrogen available, and 

 probably also the maximum for the amount of potash present 

 in the roots. On the other hand, the lowest amounts of sugar 

 for 1 of potash are, upon the whole, in Series 4, where 

 there was excess of nitrogen, great luxuriance, the lowest 

 maturation, and consequently the crudest juice. Comparing 

 period with period, the least amount of sugar for 1 of potash 

 in the roots was generally over the two years with full 

 supply of potash, but deficient supply of nitrogen, and de- 

 ficient yield of sugar. In the cases of most normal growth, 

 it would seem that there were for 1 part of potash about, 

 or nearly, 40 parts of sugar in the roots. In reference to 

 these results, it is to be borne in mind that the percentage of 

 potash remaining in the dry substance of the leaf, where 



