BEET SUGAR INDUSTRY. |1J 



One of the most important and interesting questions for scientific 

 agriculture to answer, is : In what state of fertility do we leave 

 the land for the growth of plants of a difteront character after 

 growing one species for a number of years ? For instance, the 

 root crop in Great Britain is generally considered to be a restora- 

 tive crop ; that is to say, when land was exhausted by corn 

 [English for grain] growing, a crop of roots is said to restore 

 fertility. 



Many reasons might be assigned for this Roots do not take 

 up silica. Silica is known to form compounds with ammonia, and 

 this or some other compound beneficial to corn and not required by 

 roots, might accumulate in the soil. 



As at Rothamstead we have always land under continuous corn 

 crops, it was easy to test this important question by taking cora 

 upon the land under continuous roots. It was therefore decided 

 to do this, and three successive crops of barley were taken. The 

 result showed that not only was there no accumulated fertility, 

 but that the land upon which roots had been removed year by 

 3'ear was less capable of growing barley than the land which was 

 growing barley every j'ear without manure. 



Subsequent results and recent analyses of the soil, prove that 

 roots rob the soil of more fertility than any of the ordinary crops 

 of the rotation. This is by no means inconsistent with the com- 

 monly accepted idea that roots restore fertility. In the common 

 practice of agriculture, roots are consumed on the farm, and the 

 bulk of the manure elements are returned to the land. In the five 

 years given in the table the manures were applied only the first 

 three years. The last two crops were taken without manure in 

 order to ascertain the quantity of manure remaining in the land. 



It will be found on calculating the amount of nitrogen taken up 

 in the five crops of sugar beet bulb grown by tho nitrate of soda, 

 deducting first the produce grown by the minerals alone, that the 

 quantities approximate nearly to the quantity supplied in the 

 nitrate of soda, which. would be in the three years about 260 lbs. 

 Assuming that both the cereal and root crops take a large portion 

 of the mineral food, and the nitrogen which tliey require near the 

 surface of the soil (as is probably the case) the reason why root 

 crops can take up more of the nitrogen supplied as manure, and 

 that they exhaust the soil more completely than the cereals is due 

 to the diflerent period of growth, and in the modes of treatment 

 employed in the cultivation. 



