DEFICIENCIES OF MINOR ELEMENTS 

 CAUSED BY EXCESSES 



hy Leo Gisiger, Dr.sc.techn., 



Eidg. Agrikulturchemische Anstalt, Liebefeld-Bern, Switzerland 



The Problem:— During the world war, Switzerland was 

 obliged to extend the area of its arable land. Furthermore, we, 

 Swiss agronomists, had to try, by different means, such as drain- 

 age, removing stones, rounding-off of land, breaking up of pas- 

 tures and clearing forests, to reclaim new areas for cultivation. 



On this newly acquired arable land, crop failures often oc- 

 curred in the early years. It was assumed, and the opinion soon 

 became prevalent, that the crop failures were caused by deficien- 

 cies of trace elements. This hypothesis found strong support in 

 the success obtained from using boron and manganese. The 

 more difficult the supply position of boron and manganese com- 

 pounds became, the more we had to consider these problems from 

 another point of view. 



In the course of time, it came to be of great practical interest 

 to assume that the above-named difficulties were not primarily 

 caused by a deficiency of minor elements, but by an excess of 

 lime. The following is an attempt to show by a few experiments 

 some of the relations existing between limed soils and the occur- 

 rence of the so-called "deficiency diseases." In addition, there 

 are soils, which are naturally poor in minor elements as has been 

 ascertained for boron in acid and very acid soils of cleared land. 

 I wish especially to emphasize this latter point. 



The Influence of Liming on Boron Deficiency:— T^e fixa- 

 tion hypothesis in 'partial contradiction to experiments.— The in- 

 crease of growth and of yield as a consequence of liming acid and 

 strongly acid soils is known; if excessive quantities are used, the 

 increases obtained may be less and yields may be decreased by 

 further dressings. In many instances complete infertility of the 

 soil may result from excessive liming. So far this phenomenon 

 has not been connected with an actual deficiency in one or more 



