20 T. Lyttleton Lyon and James A. Bizzell 



humidity on the surfaces of the soil particles. The percentage perco- 

 lation was in every case greater in winter than in spring, in summer, or 

 in autumn. 



Very extensive experiments were conducted by Deherain (1902) at 

 Grignon, France. His most conclusive experiments were performed 

 in concrete tanks, each of which was 2 meters square and 1 meter deep 

 and contained 5 tons of soil. The results that he considers representative 

 are for the year 1892-93. With a rainfall of 23 inches there was an average 

 of 23.2 per cent in the drainage water thru several soils, on all of which 

 crops were raised. 



Creydt, Von Seelhorst, and Wilms (1901) measured the water that 

 was conducted thru tile drains from an area of 4.81 hectares of a loam 

 soil overlying a clay loam. The tiles were 1.25 meters deep and 15 pieters 

 apart. The land was planted to beans in 1899 and to beets in 1900. 

 For the period from July 28, 1899, to August 10, 1900, the total rainfall 

 amounted to 5739 liters per hectare and the drainage water to 5027 liters 

 per hectare. The percolation was therefore 87.6 per cent of the rainfall. 

 Calculated for the year from July 28, 1899, to July 27, 1900, the rainfall 

 was 21f inches. 



Large iron cases from which drainage can be collected have been installed 

 at the Gottingen Experiment Station. These have a surface area 1 

 meter square, and a depth of 1.25 meters. They may also be weighed. 

 Von Seelhorst (1906 a) reports an experiment in which certain of these 

 cases were filled with a loam and others with a sandy soil. All were 

 kept bare of vegetation. For the calendar year 1905 the rainfall was 

 30 inches. The percolation thru the loam soil was 51.47 per cent of the 

 rainfall, and thru the sandy soil 57.08 per cent. The mean annual air 

 temperature for the year was 51.2° F., and the mean for the months of 

 June, July, and August was 70.9° F. Drainage as a rule was greater 

 from the sandy soil than from the loam. 



At the Bromberg Agricultural Institute are large lysimeters each having 

 a diameter of 2 meters and a depth of 1.2 meters. Experiments were 

 reported by Gerlach (1910 a), in which soils from five fields were used, 

 one portion of each being fertilized and one unfertilized. The experiment 

 began on June 1, 1906, and ended on July 29, 1909. The first year there 

 was no crop, the second year potatoes were raised, the third year oats, 

 and the fourth year rye. During the 1155 days of the experiment the 



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