954 AGRICULTURAL BOTANY, CHEMISTRY AND PHYSIOLOGY OF PLANTS 



ria contai»ed in the peat dust. In order to test the fertilising power of the 

 peat dust, it was used in the place of " Guanol " in 2 series of experiments, 

 and in a third it was replaced by nitrate of soda with a \aew to comparing 

 the effects of the two forms of nitrogen. A trial was also made with " Gua- 

 nol " sterilised at 100° C. to study the behaviour of the bacteria. 



The manure employed contained not more than 1.6 grams of betain 

 per 100 gms. of dried matter, so that 88 % of the betain had been converted 

 by the bacteria at the time of manufacture. It was free from superphos- 

 phate, and contained : 48.3 % of dry matter, 3.77 % of nitrogen. 



The tests were made with buckwheat, vetches, oats, beet, etc., in pots 

 manured with quantities corresponding respectively to 364,607 and 1215 

 lbs per acre. 



The tabulated results show that the peat dust added to treacle 

 lees slightly reduces the fertilising power of the manure. The nitrogen in 

 the peat exerts no action, the nitrogen of the lees being alone active. 



Sterilised " Guanol " gives the same yield as when unsterilised, which 

 proves that the bacteria in " Guanol " have no specific influence on the 

 growth of the plant, at any rate where the soil is rich enough in humus. 

 These experiments will be repeated in soils poor in organic matter. Poss- 

 ibly too the sterilisation was not complete enough to destroy all the bacte- 

 ria of " Guanol '". 



In the 3 series where a dressing was applied in the proportion of 364, 

 607 and 1215 lbs of " Guanol " per acre, an increase in yield was obtained 

 proportional to the increased quantity of manure. The nitrogen in the 

 " Guanol " however does not act so well as the nitrogen in nitrate of soda, 

 being present in slightly less assimilable forms. 



The researches of the writer into the nitrification of " Guanol " show- 

 ed that at the end of 8 weeks 30.04 % of the nitrogen of " Guanol " was 

 converted into nitric acid. The nitrogen of nitrate of soda is more easily 

 conveyed into the subsoil by water than that of " Guanol ". These enqui- 

 ries also proved that the specific bacteria of " Guanol" do not promote am- 

 monification or nitrification to any great extent. 



Other manuring tests undertaken on grass-lands, grain crops, beets, 

 etc., are not yet completed. 



AGRICULTURAL 



BOTANY. 



CHEMISTRY 



AND 

 PHYSIOLOGY 

 OF PLANTS. 



741 - Studies on the Root System of Plants, in Reference to Selectionand Drought Re- 

 sistance. — MODESTOV A. P.: I. Differences in the Dimensions of the Root System in 

 different Tj-pes of Cultivated Plants, in liopHCtiuH ciininwKi )iii)aHf/Hticiiibix7> pa- 

 cmcHiu (Root System of Cultivated Plants), Part I, pp. 11-44 -r - tables -f 3 plates. 

 Moscovf, 191 5. — II. Depth reached by Roots under normal Conditions of Growth. Ibid., 

 pp. 46-80 -f- 14 tables and diagrams. — III. Contribution to the Study of the Root 

 .System of Flax. Ibid., pp. 101-118 -\- i table -|- i diagram. 



Remarkably little study having been devoted to the underground por- 

 tions of plants as compared with the parts above ground, the writer under- 

 took a series of methodical investigations of the root system of herbaceous 

 plants, cultivated and wild, in the laboratories and experimental Stations 

 of the Agronomic Institute of Moscow, with the assistance of the Depart- 

 ment of Agriculture. The starting point in these enquiries was the fact, 



