Lecture 1 



9 — 



Survey 



placed many times in the soil solution, from the solid 

 phase of the soil, and to varying degrees the same 

 was true of other ions. The concept of "supplying 



* Bictibonate and pbosphate remain as in table 1 (see text.) 

 t SoO not available for study. 



Table 2. — Composition of displaced solutions from cropped, fal- 

 lowed and original soils, after 8 years. (Results calculated to an ap- 

 proximately uniform moisture basis for each soil). These data illus- 

 trate the general magnitudes of concentration, for different ions pres- 

 ent in the soil solutions of the soils discussed in the text. The so-called 

 fallowed soils were actually cropped the first year and were cultivated 

 and irrigated the first four years. The remaining four years they 

 received no treatment other than irrigation (distilled water). The prin- 

 cipal interest of the table for present purposes is to give an idea of 

 the relative concentrations of different solutes and the effects cropping 

 have had on these concentrations. The value for the stored and fal- 

 lowed soils, S and B series should be compared with those for the A 

 series. Note the differences in magnitudes of concentrations for NO3, 

 K and PO^. (From J. S. Bukd and J. C. Martin, 1924). 



power" of the soil had to be invoked to understand 

 the nutrient capacity of the soil. Soil solution data 

 alone were inadequate to explain the potentiality of 

 the soil for delivering nutrients to the plant over 

 extended periods of time. As the years passed, soil 



