AGRICULTURAI, BOTANY, CHEMISTRY AND PHYSIOLOGY OF PLANTS 1 259 



Osmotic Pressure of the Soil Solution and Character of the Grain 

 of " Bielotonrka " Wheat. 



I 



the whole of the grain becomes glassj-, while with sodium chloride and so- 

 dium sulphate at the same osmotic pressure only 20 % of glassy grains are 

 produced. 



The presence of nitrogen in the basic or acid radicle of a salt reacts 

 on the quantity of glassy grains in the crop : for all ammoniacal salts, as 

 likewise for sodium nitrate, even at low osmotic pressures (1.5-2.0) the whole 

 of the grain is glassy. Thus, between glassiness of the grain and the pre- 

 sence in the soil of a quantity of nitrogen in excess of that found there, nor- 

 mally a very clear connection exists, viz : the increase of nitrogen in the 

 nutrient medium entails an increase in the quantity of grain with glassy 

 fracture. 



With a view to better studying the glassiness of the grain, the Station 

 in 1913 made an anal^^sis of this grain as to its total nitrogen content ; the 

 " Bielotourka " grain was taken from a single pot in which the humidity 

 of the soil had been maintained at 24 % of its total weight in the absolutely 

 dry state ; this grain was divided into three groups according to the charac- 

 ter of the fracture. 



The following results were obtained : the glassy grain represented about 

 20 % of the total quantity, and contained 2.02 % of nitrogen ; the glassy- 

 flour}^ grain formed 38.3 % and contained 1.80 % of nitrogen, and finally 

 the floury grain formed 41.7 % and contained 1,62 % of nitrogen ; it fol- 

 lows that the glassy grain contains a larger quantity of nitrogen than the 

 floury grain. Similar investigations were made into the soft wheat grain 

 " Poltavka ", produced under conditions identical with those of " Bielo- 

 tourka " the glassy grain of the soft wheat contained 2.08 % of nitrogen 

 and the floury 1.83 %. 



The quantity of nitrogen in the glassy grain increases with the increase 

 of the osmotic pressure of the soil moisture determined both by nutrient 

 and non-nutrient salts, and with the increase in the percentage of glassy 



