105 Jamalainen: Trace Elements in Finland 



formation regarding the importance of manganese in plant culti- 

 vation and diseases caused by lack of manganese is not available 

 for Finland, except for the Marsh Spot disease, a disease observed 

 in peas which has occurred in only two cases (Jamalainen 

 19361?) in Aland (the archipelago in the southwestern part of 

 Finland). It is evident that there is no general lack of manga- 

 nese in Finnish fields which is due to the general acid reaction 

 of the soil. This does not mean, of course, that there may not be 

 a lack of manganese in Finland in soils which have been heavily 

 limed. 



Conclusion:— The investigations carried out so far do not, as 

 yet, give a clear picture of the full importance of boron and copper 

 in the practice of agriculture in Finland. They show that the lack 

 of boron, as well as of copper, is very common in our fields. 

 Many significant questions about the importance of trace ele- 

 ments in plant cultivation are still awaiting further study. There 

 should be a thorough investigation to determine in which parts 

 of the country and under which conditions lack of copper and 

 boron is found. The reasons for the great variability in the oc- 

 currence of the deficiencies, not only in different localities, but 

 in the same locality, must also be investigated. Attention will 

 also have to be given to other trace elements, not mentioned here, 

 and their importance in crop production. 



Addendum:— Recent data about the occurrence of boron in various 

 regions of Finland (Jamalainen 1949) show that boron deficiency is com- 

 mon in the provinces of Uusimaa, Hame and Turku, and to some extent in 

 Pori. Additional boron is required also in the provinces of Kuopio, Mikkeli, 

 and Kymi. In the districts, bounded by the Gulf of Bothnia, boron de- 

 ficiency is less common.— Information about manganese deficiency diseases 

 has been received from Uusimaa (oats, timothy, and red clover), Ahvenan- 

 maa (oats), and Hame (raspberries). 



