Effect of Manganese Compounds 89 



The bulbs and leaves were considerably stimulated by small doses of 

 manganese sulphate, the best results being obtained from (2), which 

 represents a manuring of 22 kgm. MnSO 4 per hectare. An increase 

 of the dose lessens the beneficial effect, as the toxic action begins to 

 come into play. The actual figures obtained may prove of interest. 



Wt. leaves Wt. bulbs Total weight Bulbs & roots 



& roots Absolute llelative leaves 



gm. gm. gm. gm. 



1. 29-5 8-5 38-0 lOO'O -28 



2. 38-0 22-5 60-5 159'2 '59 



3. 35-5 16-5 51-0 134-2 '46 



Uchiyama (1907) carried on a variety of experiments with man- 

 ganese sulphate on several plants on different soils, both in the 

 field and in pots, and found that the compound exercised a favourable 

 action in most cases when applied in appropriate quantities. In 

 summarising his results he stated that both manganese and iron 

 stimulate the development of plants, different plants varying in their 

 susceptibility to the action. Sometimes a joint application of the two 

 salts is the most beneficial, sometimes an individual application is the 

 better, in which case manganese sulphate is generally better than ferric 

 sulphate in its action. The stimulating action of manganese varies 

 greatly with the character of the soil, and the mode of application 

 also affects results. As a general rule the manganese acts best when 

 applied as a top dressing rather than when added together with the 

 manure. Further the stimulating action differs greatly with the 

 nature and reaction of the manurial mixture. Uchiyama concludes 

 that 20 50 kgm. per hectare of crystallised manganese sulphate is 

 a good general amount to apply. 



Takeuchi (1909) corroborates the statements of the various writers 

 that plants differ in their response to the manganese manuring. Pot 

 cultures, in each of which 8 kgm. soil were similarly manured, received 

 2 gm. MnSO 4 . 4H 2 applied as a solution of 1/100 strength, the controls 

 receiving the same amount of water. The manganese increased the 

 green weight of spinach by 41 %, while the dry weight of barley, peas 

 and flax rose 5'3 %, 19'4%, and 13'9% respectively above that of 

 the untreated. The control plants of flax were behind the manganese 

 plants in growth and flowering, while barley was the least stimulated of 

 all the test-plants. Other observations seemed to show that Legumi- 

 nosae and Cruciferae are more susceptible to manganese stimulation 

 than are the Gramineae. 



