6 BULLETIN 42, U. S. DEPARTMENT OF AGRICULTURE. 



Repeated applications of small amounts in the form of top-dressing 

 seem more favorable than a single application of the same amount 

 of manganese salts at the time of manuring before the seed is sown. 

 The stimulative action also seems to differ greatly with the character 

 of the soil. Leidreiter, 1 working with oats, mustard, beets, and pota- 

 toes, found manganese to have a beneficial effect. Similar results 

 were obtained with beans with small amounts of manganese; large 

 amounts, however, were injurious. Manganese showed best effects 

 on humus soils, next on clay soils, and least on sandy soils; this, 

 however, varied to a certain extent with the kind of plant and the 

 form of the manganese. Labergerie 2 found manganese less effective 

 in wet soils than dry, also found that manganese chloride was more 

 effective when used with potassium sulphate. 



A very extensive experiment was made by Uchiyama 3 on the 

 action of manganese with different manurial mixtures on two soils 

 having widely different characteristics. A variety of crops were 

 grown, including the cereals, legumes, and vegetables. Each crop 

 was stimulated by the treatment, the increase varying from 5 to 60 

 per cent. The legumes were most benefited. Repeated applica- 

 tions as top-dressing throughout the period of growth gave better 

 results than other methods of applying the substance. The amount 

 of manganese salts gave best results when applied at the rate of 20 

 to 50 kilos per hectare. In these experiments it was found that the 

 manganese, when applied with fertilizers that have a neutral reaction 

 and to soils that were neither acid nor alkaline, had a better effect 

 than when there was an acid or alkaline condition. 



Takeuchi 4 found that leguminous and coniferous plants were 

 stimulated more by manganese than were grasses. Barley and 

 other grains were least stimulated. 



Kelly's 5 work at the Hawaii experiment station showed that some 

 plants were less affected by manganese than others. He worked 

 with a soil that was very high in manganese. Pineapples were 

 seriously injured. Corn, peanuts, beans, cowpeas, and a number of 

 the other legumes were also more or less injured. Sugar cane was 

 not so much affected. Certain weeds, cotton, and a number of the 

 truck crops were unaffected. 



The results of experiments with manganese as a fertilizer have 

 been variable. In general the effect has been a beneficial one. In 

 many cases, however, growth has either been retarded, or there has 

 been no action. This may be due to certain soil conditions. Few 



' Leidreiter, P., Behavior of manganese in the soil toward some agricultural plants. Inaug. Diss. 

 Rostock. (1910). Biedermann's Zentr., 40, 531. 



* Labergerie, Semaine Agr. Paris, 26, 331 (1907). 



* Uchiyama, Influence of stimulating compounds upon the crops under different conditions. Bui. Imp. 

 Centr. AgrL Exp. Sta., Japan, 1, No. 2, 37 (1907). 



* Takeuchi, Difference of susceptibility of plants to stimulation. Jour. Col. Agr., Tokyo, 1, 207 (1909). 

 b Buls. 23, 26, 28, nawaii Expt. Sta. 



