WATER SOILS. 333 



The influence of climate upon the lime content and humus of the 



soils of these different regions is discussed, as well as the origin and 

 treatment of alkali in the western or arid portion of the State and the 

 adaptability of the various soils to different systems of farming. 



The importance of the mineral humates as a nutritive medium 

 for plants, (1. Xefedov (Selsk. Khoz. i Lyesov., 184 1897), -Ian., pp. 

 141-163). — The question which the author seeks to answer is whether 

 the phosphorus and nitrogen which enter into the composition of the 

 humus compounds of the chernozem (black Russian soil) are assimi- 

 lable by the higher plants under the ordinary conditions of cultivation, 

 i.e., in the presence of microorganisms. 



The experiments carried out consisted in the first place of a repeti- 

 tion of the experiments of Eggertz with a soil washed with a dilute 

 mineral acid, precautions being taken to carefully neutralize the soil after 

 this treatment, and in the second place in growing plants in humus 

 substances extracted from the chernozem, inoculating the humus ex- 

 tract with the bacteria of the soil. In order to neutralize the soil after 

 treatment with the acid and distilled water the free humic acids were 

 saturated with calcium carbonate. 



The experiments, were made with the chernozem of the Tula Govern- 

 ment. The composition of the air-dried soil was as follows: 



Analysis of air-dried chernozem. 



Per cent. 



Hygroscopic water 5.97 



Humus with water of crystallization 10. 16 



Phosphoric acid obtained by igniting the soil and treatment 



with boiling 30 per cent hydrochloric acid 1702 



Nitrogen o77 



Air-dried humic acid (calculated to ash-free matter; 4.87 



In the humus there was found 1.S8 per cent of phosphoric acid, which 

 represents 51. (J per cent of all the phosphoric acid of the soil. 



In the repetition of Eggertz's experiments part of the soil was treated 

 with 1 per cent hydrochloric acid and part with 3 per cent. After 

 washing with distilled water a small portion was at once dried on filter 

 paper, while the greater part was first mixed with chalk, using 100 gin. 

 of chemically pure carbonate to 200 gm. of the air-dried soil. Before 

 placing in the glass cylinders where the plants were grown the 

 various soil samples were pulverized and mixed with different nutri- 

 tive solutions. 



The material for the experiments with the pure calcium humates was 

 prepared as follows: The soil was treated with 1 per cent hydrochloric 

 acid, washed with distilled water, dried on filter paper, pulverized, 

 and placed in layers 1 cm. thick in tin sieves whose bottoms were cov- 

 ered on the inside with a layer of filter paper. The soil was treated 

 with ammonia solution (1 part of strong ammonia and •"> parts i4' wat< 

 the solvent remaining in contact with the soil for from 15 to 30 minutes, 

 and then the soil was washed with distilled water. The black extract 



