In a study of the effect of different treatments on the microbial activity and the availability of manganese in manganese-deficient soil it was found that the application of cyanogas significantly. reduced the density of population of manganese-oxidizing, denitrifying, and cellulose-decomposing organisms. Only on the 101st day after treatment did the manganese-oxidizing and denitrifying organisms reach the same density as that in the soil treated with manganese sulphate, mulch, or in the control soil. The density of cellulose-decomposing organisms remained depressed to the end of the experiment. Application of manganese sulphate and straw mulch resulted in an increased activity of cellulose-decomposing, denitrifying, and manganeseoxidizing organisms. Results of chemical analyses indicated that the water-soluble manganese was not affected by the different treatments, but remained practically at the same level throughout the experiment. Re laceable manganese was found to be higher in calcium-cyanide-treate i? soil than with any other treatments and was still 10 times higher at the end of the experiment. The highest content of easily reducible manganese was found in the manganese-treated soil, and it remained higher than in any other treated soil throughout the experiment. Analysis of the data of the microbiological tests and of the content of available manganese indicated a negative correlation throughout the experiment between the density of cellulose-decomposing organisms and replaceable manganese, and the same type of correlation was established between the density of manganese-oxidizing and denitrifying organisms and replaceable manganese until the 101st day after treatment.

Text in English

Reprints Collection