— 37 — 



The moment of this deep exhaustion of the humid layer by the 

 winter corn is the commencement of the formation oi the intermediate 

 dry layer. In the approching autumn, after the winter corn has been 

 cleared away, the periodical humid layer commences to form on the 

 surface: and in the winter preceding the sowing of spring corn we already 

 find all our three layers: the upper periodical humid (from the surface to 

 40 cm.) the intermediate dry (from 60 ••) to 180 cm ) and the perma- 

 nent humid layers (from 180 cm.--"') and deeper to the ground water). 



Towards the time for sowing spring corn (barley) on fig. 10 the 

 state of humidity with barley is shown for 1905, a dry year — the thickness 

 of the humid layer was about 40 c m. We saw that the lenghth of ripe 

 barley roots equal 110 cm. It is obvious that with a thickness of the 

 humid layer of 40 c m., the root will only reach that depth and then 

 cease their growth, having met with an obstacle which they cannot pass, 

 in the shape of the intermediate dry layer. The life processes in the 

 growth of barley, suffer from such a shortening of the roots first of all, 

 in this respect: that instead of long main roots the side roots will com- 

 mence to develop strongly and there is not sufficient water for a fresh 

 quantity of roots. The plants, hav'ng formed a root-system shorter than 

 others and proved themselves to be in a horizon of the utmost dryness, 

 perish in various spates of development. Others, forcing their roots a littl 

 deeper give a v/eak crop of partly developed grain; and finally those 

 which reach the deep horizons before the others give a more or less 

 normal grain. In 1905 the crop was certainly very poor-about 30 poods, 

 comparatively ' :; of the normal, and the humid layer ot 40 c m. Was 

 also about ' .■•, of the normal thickness of the rootinhabitable layer for barley. 



In moister years at the approach of the period for sowing spring 

 corn the thickness of the moistened soil layer fluctuates from 79 to 100 

 c m.; nevertheless, the v/ater entering the soil from the autumn, winter 

 and spring deposits, are insufficient to moisten the intermediate dry layer. 



Therefore, with threecourse bare fallow rotations, a part of the useful 

 water accumulated durind fallow remains unused by the winter grasses 

 sinks into deeper soil horizons and makes up the loss of water in the 

 permanent humid layer. Obviously, the oftener the field is put under fallow 

 the nearer the permanent humid layer will approach the surface with 

 every years fallow, and the thinner and thinner the intermediate dry 

 layer will become. 



e 



") Between 40 and 60 cm. lies the changing layer from humid to dry, 

 holding l"'u and not more than 2" u of useful water-shaded a light grey tone. 



■•■■) Above it lies also the changeable layer, holding as much water as 

 the upper one-shaded a light grey tone also. 



