392 INVESTIGATION BY CULTURE EXPERIMENTS 



Table 70. The land was known to have been used for meadow and 

 pasture for at least two centuries previous to the beginning of these 

 experiments. 



The field was known as The Park, and consisted of normal, nearly 

 level upland soil, very similar to Agdell, Broadbalk, Hoos, and 

 other Rothamsted fields, except that The Park had not been heav- 

 ily chalked in the earlier years, while the other Rothamsted fields 

 (with the exception of Geescroft at least) had received chalk dress- 

 ings probably amounting to 100 tons or more of calcium carbonate 

 per acre. 



The Rothamsted Station has no knowledge of any grass seed 

 ever having been sown on The Park, either before or since the 

 beginning of the experiments. From 1856 to 1874 only the first 

 crops were harvested and weighed as hay, the second crops having 

 been fed off by sheep, as a rule, and the sheep having been con- 

 fined upon the plots so that the droppings were returned to the 

 respective plots. Since 1874, the second crops, when sufficient in 

 amount to justify it, have also been harvested and removed as hay. 



On a few plots the treatment was not fully decided upon until a 

 few years after the beginning of the experiments. Thus, plot n 

 was divided in 1862, when the addition of sodium silicate was 

 begun on 11-2. At the same time the application of potassium was 

 discontinued on plots 8 and 10 and the sodium sulfate changed from 

 200 pounds to 500 pounds for 1862 and 1863 and then to 250 

 pounds. The periods represented in the first column of averages 

 vary from 7 to 10 years. 



In studying the results from Table 70, it should be kept in mind 

 that all applications have been made only as top-dressings; and, 

 consequently, that benefit could be expected only from those 

 materials which were sufficiently soluble to permit of their being 

 carried into the soil to the depth where the plant roots secure 

 considerable amounts of their food supplies. It should be kept in 



NOTES TO TABLE 70. The "minerals" regularly included 392 Ib. of acid 

 phosphate (400 Ib. of basic slag, 1897 to 1902), 500 Ib. of potassium sulfate (300 Ib. 

 for 1878 and previously), 100 Ib. of magnesium sulfate, and 100 Ib. of sodium 

 sulfate (200 Ib., 1856 to 1863), but where potassium was omitted (plots 8 and 10), 

 the sodium sulfate was increased to 250 Ib. from 1864 to 1904. The farm manure 

 applied to plots i and 2 was at the rate of 15.7 tons per acre for the eight years, 

 1856 to 1863. 



