Lysimeter Experiments 67 



the rate of 3.92 tons per acre, (2) ground coral, at the rate of 8.87 tons 

 per acre, and (3) gypsum, at the rate of 11.08 tons per acre. The effect 

 of gypsum was to increase the quantity of potash (K2O) in the drainage 

 water at the rate of 198 pounds per acre, but burnt hme and coral caused 

 a loss of only 9 pounds per acre. 



Lysimeters have been in use at the Bromberg Agricultural Institute 

 since 1906. They are cylindrical in shape, and are 2 meters in diameter 

 and 1.2 meters deep. Experiments reported by Gerlach (1910 a) cover 

 a period from June 1, 1906, to July 29, 1909. Five soils were used in 

 ten lysimeters, one tank of each soil being fertilized and one left unfertilized. 

 The first year of the experiment no crops were raised; the second season 

 all the tanks were planted to potatoes, the third season to oats, and the 

 fourth season to rye. 



The average yearly loss of calcium oxide (CaO) for the period of experi- 

 mentation, including the year of fallow, varied with the different soils 

 from 103 pounds per acre to 1803 pounds on the unfertilized soils. It may 

 be remarked that there was less removal of both calcium and potassium 

 in the drainage water of the fertilized soil than in the water from the 

 unfertilized soil. The annual removal of potassium ranged from 9 pounds 

 to 206 pounds per acre. 



Another experiment with the weighable lysimeters at Gottingen is 

 reported by Von Seelhorst and others (1913). Two tanks were used, 

 one of which was filled with a loam soil and the other with a sandy soil. 

 Both were kept bare of vegetation thruout one of the experiments, which 

 continued from 1908 to 1912. The average annual removal of calcium 

 oxide (CaO) amounted to 239 pounds per acre from the loam and 216 

 pounds from the sand, and of magnesium oxide (MgO) 42.5 pounds per 

 acre from the loam and 19.2 pounds from the sand. 



Experiments with lysimeters at the Florida Experiment Station are 

 reported by Collison and Walker (1916). The tanks were 4 feet deep 

 and had a surface area of approximately 1/2000 acre. The soil was a coarse 

 sand, poor in plant-food materials, especially in potash. In four of the 

 tanks peach trees were planted. Each tank was fertihzed twice a year 

 with two pounds of a mixture containing eight per cent of potash. The 

 other fertilizer ingredients also were applied on this liberal basis. In 

 tanks 1 and 2 the nitrogen was in the farm of ammonium sulfate, in 

 tank 3 nitrate of soda, and in tank 4 dried blood. Of the bases, definite 

 figures are available for potash only. For the four years froni 1912 to 



67 



