103 Jamalainen: Trace Elements in Finland 



Boric fertilizers began to be widely used in Finland for 

 preventing internal cork of apples and other deficiency diseases 

 before the recent wars. During the war years boron was not 

 available, and even in 1947 we still did not have enough boron con- 

 taining fertilizers for our crops. 



Clover (Trifolium fratense) .—The effect of boron on the de- 

 velopment of clover was investigated in 1946 in a number of 

 fertilizing experiments. The results were positive— in three ex- 

 periments out of five, boron considerably increased the yields 

 (450-1.100 kg per hectare). These experiments suggest that 

 clover needs considerable boron in Finland. 



Of other plants found to be affected by boron deficiency, in 

 Finland, the following may be mentioned: Cracked Stem of celery 

 CAfium graveolens), Heart Rot of red beet (Beta vulgaris v. ra^a 

 f. rubra), Brown Heart of turnips CBrassica camfestris v. ra'pa'), 

 and a boron deficiency disease in white mustard CSinafis alha). 



Copper:— The question of copper has been fairly thoroughly 

 investigated at the Department of Agricultural Chemistry and 

 Physics of our Agricultural Research Centre. Mr. Tainio, 

 M.A., gave an account of these investigations in 1946. 



Experiments with copper have been carried out since 1939, but 

 to a large extent only during recent years. For this purpose 160 

 field experiments were carried out in different parts of the country 

 with different plants and on a variety of soils. Copper sulfate 

 and domestic copper slag were used as copper fertilizers in these 

 experiments. Copper slag is a residue produced after the refining 

 of copper. It contains about 0.6% of copper. In addition to this, 

 copper slag contains small amounts of other trace elements, but 

 according to present experience it may well be regarded as a copper 

 fertilizer. As the percentage of copper in the slag is very low, 

 heavy dressings have been used in the experiments, 300-900 kg per 

 hectare. 



The different reaction of various soils to copper treatment 

 has been determined in experiments with spring cereals. Accord- 

 ing to these experiments a peaty soil has the greatest need for cop- 

 per. In 41% of all cases the increase in yield was definite. In 

 sandy soil and fine sand the corresponding percentage was 34%. 

 Clay soil seems to be least in need of copper: only 22% of the 

 soil investigated showed definite increases in yield. In 36% of 

 our experiments, with all plants and all soils involved, copper fer- 



