Rothamsted Symposium on Trace Elements 104 



tilizing definitely increased the yields. The results of the experi- 

 ments, however, show considerable variation in different years. 



The increases in yield observed in the experiments were note- 

 worthy. In the years 1939-1944, copper fertilizing increased the 

 yield of grain for spring cereals, by 400 kg per hectare in sandy 

 soil, by 450 kg per hectare in peaty soil, and by 200 kg per hectare 

 in clay soil. In a number of instances the increase of yield was 

 600-700 kg per hectare, and even exceeded 1000 kg of grain per 

 hectare. In experiments with hay, potatoes and roots the increase 

 was also considerable. In addition to this, copper manuring has 

 been observed to have a beneficial effect even in the next year. 



No definite difference can be observed in the effect of copper 

 sulphate (50 kg per hectare) and of copper slag. Likewise, the 

 differences due to different amounts of copper slag are indistinct. 

 Copper slag has been placed on the market in Finland, and 300- 

 600 kg per hectare has been recommended as a suitable amount to 

 be used. 



The question as to which areas of Finland require copper 

 dressing, cannot be anwered with certainty, but results indicate 

 that northern Ostrobothnia, some parts of central and southern 

 Ostrobothnia (in the western part of northern Finland) as well as 

 of central Finland are in greater need of copper than other parts 

 of the country. 



In some parts of northern Finland the 'licking sickness" of 

 cattle has been found as a result of a lack of copper in the soil. 

 Affected animals recovered when they were given copper sulphate. 

 Crops also suffer from lack of copper in these districts, and copper 

 fertilizing will increase the yield of grain for spring cereals by 

 nearly 2000 kg per hectare! 



The plant diseases due to lack of copper have not been closely 

 investigated in Finland. In some cases barley and oats were chlo- 

 rotic at the tips of the leaves in the regions suffering from lack of 

 copper. This can be regarded as a typical Reclamation Disease 

 due to a copper deficiency. On the whole, signs of copper defi- 

 ciency have not been observed whenever copper fertilizers in- 

 creased the yield. 



Manganese:— The work by Erkama, published in 1947, which 

 illustrates the physiological importance of copper and manganese 

 in plants, is likely to contribute to the investigation of the influ- 

 ence of manganese in the agriculture of Finland. Detailed in- 



