142 



SCIENCE AND SOIL 



ing loamy at about 3 feet. It is a common type of soil in the Atlantic and 

 Gulf Coastal plains. The surface is level to rolling, and the soil is well drained." 



"Our own observations, published by the Bureau of Soils (Bulletin No. 26), 

 have demonstrated that four good soils, observed to produce two and a half times 

 the yield per acre of corn and potatoes that four poorer soils did under identical 

 treatment, also gave up, when washed three minutes in five times their weight of 

 pure water, 2.58 times as much plant food. Not only was there this difference in the 

 amount of plant food carried in water-soluble form in the best and in the poorer 

 soils, but the amounts of this same plant food taken out of like areas of field by like 

 numbers and like kinds of plants during the same time was 3.2 times as great in the 

 sap of the plants which gave the highest yields." (Proceedings Jamestown Con- 

 gress of Horticulture, 1907, page n.) 



The following tabular statement is a summary of Professor King's data secured 

 under known conditions from the eight soils mentioned. (See Bureau of Soils 

 Bulletin 26, page 120.) It should be stated that each value recorded for plant 

 food determined is the average of 28 different determinations. These data are 

 certainly far more trustworthy than the selected results from such miscellaneous 

 samples as are referred to by Professor Whitney in Bulletin 22 (see above quotation). 



AVERAGE CROP YIELDS AND MEAN AMOUNT OF WATER-SOLUBLE PLANT 



FOOD IN FOUR POOR SOILS AND FOUR GOOD SOILS FOR THE 



SEASON OF 1903. By F. H. King 



POOR SOILS 



GOOD SOILS 



CROP YIELDS PER ACRE: AVERAGE OF FIVE PLOTS FOR EACH SOIL 



POUNDS OF WATER-SOLUBLE PLANT-FOOD ELEMENTS IN 4 MILLION 

 POUNDS OF SOIL: AVERAGE OF 28 DETERMINATIONS FOR EACH SOIL 



