233 



potassium and ammonia as well as phosphoric acid, which had been ab- 

 sorbed by the friable soil. Nitrates, because of their easy solubility, at any 

 rate, are lost in larger amounts, but they are also partially washed away 

 from undrained soil into the subsoil. 



Further, the soil capacity for heat, increasing with drainage, should not 

 be underestimated as well as the improvement of the crop produced, of 

 which it may be said in general that damp, and therefore cold, soil produces 

 crops poorer in nutriment. The reason why damp soil is cold is evideni 

 from considering the fact that if water has a specific heat equal to one, the 

 highest specific warmth ever shown by soil is only equal to 0.5 ; i. e. at most 

 lialf that of water. If this water which is the hardest to warm is removed 

 by drainage, the soil must become warmer. Previous to drainage, the soil 

 remained cold until late in the spring, thus causing a later awakening of 

 vegetation and a later germination of the seed. A cold place of growth is 

 especially disturbing to young plants, since it holds development back in a 

 developing phase, which is determinative for the whole later plant. The 

 root system becomes poor, the appearance sick, and later favorable temper- 

 ature conditions are not able to overcome the bad condition. One of Stock- 

 hardt's^ experiments with winter rye may serve as an example. The ex- 

 perimental plots differed in drainage and soil porosity. One plot was 

 traversed at a slight depth by a drain possibly 2.5 cm. wide and in such a 

 way that the pipe, bent at right angles at one end of the drain, opened like 

 a chimney toward the upper surface of the soil. The soil of this plot, as 

 well as that of the undrained one, was broken up 50 cm. deep, while a third 

 plot was dug only 25 cm. deep and not drained. In corroboration of earlier 

 results obtained with lupin, oats and the like, the harvest showed an ap- 

 preciable excess on the drained lot, although the young plants showed no 

 difference before spring. 



Reckoned per acre this crop amounted as follows : 



Grain Straw Totals 

 and Chaff 



kg. kg. kg. 



Part I, drained and dug 50 cm. deep 539 1470 2009 



Part II, undrained and (lug 50 cm. deep 411 928.5 1339-5 



Part III, undrained and dug 25 cm. deep 338 859-5 1 197-5 



Grain content Nitrogen content 



per bu. of the grain 



Lot I. 40.80 kg. 2.18 per cent. 



Lot II. 39-85 kg. 1.83 " " 



Lot III. 37-70 kg. 1.83 " " 



Patz-, referring to the use of drainage for removing iron from neivly 

 broken soil, says, "usually iron is found directly under the surface of the 

 soil and at the height of the usual ground water level. The ground water 



1 Chemische Ackersmann, 1859, p. 232; IcSGl, p. 100; 1864, p. 22. ,, ^ ^ ., 

 ^ Hannoversche landw. Zeit. 1880, No. 45; cit. Biederm. Centralbl. f. Agnk.- 

 Chemie, 1880, p. 911. 



