244 THE SMALL GRAINS 



of finely divided particles is well shown in the mechanical 

 analyses made under the direction of Milton Whitney, 

 Chief of United States Bureau of Soils. Comparing the 

 results of those of the Chernozem samples with those of 

 the samples from North Dakota, a very close similarity 

 is noted, each series showing a large proportion of the 

 small particles, but especially very fine sand, silt, and 

 fine silt. There is thus provision for great absorption 

 and retention of water. Samples from the famous " Blue 

 Grass " district of Kentucky, as would be expected, seem 

 to be in good physical condition. Nevertheless, the 

 smaller actual moisture content and much smaller per- 

 centage of organic matter even in these samples indicate 

 less water capacity and a smaller source of nitrogen. 



Samples of the Argentina steppe soils, including those 

 of the northern part of the plains of Patagonia, have also 

 been studied by the United States Bureau of Soils, and 

 the mechanical analyses have shown the same special 

 qualities found in the prairie soils of Russia and North 

 America, namely : (1) a large percentage of finely divided 

 soil particles, (2) a high percentage of organic matter, 

 never less than 4 per cent, and from that to 7 per cent, and 

 (3) a percentage of moisture in air dry samples ranging from 

 3.28 per cent to 9.68 per cent, with only two samples out 

 of 25 under 5 per cent. Of the 8 samples showing 8 per 

 cent or more of moisture, all but one came from Chubut. 

 All samples showing very high percentages of clay, 50 per 

 cent or more, also came from Chubut, where the wheat of 

 best quality in Argentina is grown. These Chubut soil 

 samples also contain the highest average percentage of 

 organic matter. 1 



1 All these soil samples, from the Great Plains, the Russian 

 Chernozem, and Chaco-Pampean Plains, were obtained by the 



