WATEE SOILS. 



27 



The total salts in the surface foot of the cultivated soil reached a maximum July 1, 

 from which date they rapidly declined until they reached a minimum August 1. In 

 case of the uncultivated crops — clover, alfalfa, and oats — the soluble salts increased 

 rapidly at the beginning of the season, reaching a maximum about May 1. From 

 this date they slowly decreased until the 1st of July, and then remained stationary 

 until August, after which they rose again until September 1, when they were prac- 

 tically the same as at the beginning of the season. 



" If comparison is made between the changes in nitrates in the second, third, and 

 fourth feet and in the total soluble salts for corresponding depths it will l)e seen that 

 the curves generally go through the same phases throughout the season under both 

 the cultivated and not cultivated crops, each rising and falling together, but through 

 a nuu'h greater amplitude with the total salts where the amounts are so much larger. 



"The most striking difference between the seasonal changes, both of nitrates and 

 total salts, in the lirst foot of soil, and in the next 3 ft., is found in the much greater 

 fluctuations recorded for the surface. 



"The relation existing between the amount of nitric nitrogen in field soils com- 

 puted as calcium and magnesium nitrates and the total soluble salts as indicated by 

 the electrical resistance appears to be widely variable under different conditions. 



"The ratio of total soluble salts to the nitrates in the surface foot of the five culti- 

 vated fields is, on the average for the whole season 2.14 to 1, while in the surface 

 foot of the clover fields it is 4.8 to 1. For the second, third, and fourth feet for the 

 season the ratio is 7.29 to 1 for the corn and potato fields, and 9.97 to 1 for the clover, 

 alfalfa and oats." 



It was found that the largest yield of corn was not associated with the highest per- 

 centage of nitrates In the soil, but with the largest amount of soluble salts. 



The results of the season's observations show that extremely small amounts of 

 nitric nitrogen may occur in a soil on which plants make vigorous growth and pro- 

 duce large yields. With the right amount and distribution of water large yields 

 may be produced when the nitrates in the surface foot of soil are as low as 24 lbs. 

 per acre in case of corn, 45 lbs. in case of clover, 19 lbs. with alfalfa, and 105 lbs. 

 with potatoes. 



Influence of potash salts on black marsh soils, F. H. King and A. R. Whit- 

 son ( Wisconsin Sta. Rpt. 1900, pp. 197-W3, fig. 1) . — In continuation of previous experi- 

 ments (E. S. R., 12, p. 32), tests were made at the station of the relative effective- 

 ness of ( 1 ) potassium sulphate, potassium chlorid, potassium-magnesium carbonate, 

 and kainit; and (2) potassium sulphate and chlorid applied in different ways and at 

 different rates. The potash salts were aj^plied to corn at the following rates per acre, 

 furnishing equal amounts of iwtash: Sulphate, 263.3 lbs.; chlorid, 171 lbs.; potash- 

 magnesium carbonate, 649.8 lbs.; kainit, 644.6 lbs. Comparing the yields of the 

 fertilized rows with the parallel unfertilized rows, counting the latter yield as 1, the 

 following results were obtained: 



Increased yield of corn with, potasli scdts, counting yield vitJiout potash «s 1. 



Increase Increase 

 of stalks, of ears. 



With equal amounts of potash: 



023.3 lbs. potassium sulphate 



171 lbs. potassium chlorid 



C49.8 lbs. potiissium-magnesium carbonate 



(! 1 1.G lbs. kainit 



With (liffercnt amounts of potash: 



040 lbs. potassium sulphate 



320 lbs, p( itassium .sulphate 



171 lbs. [Kitassinui clilorid 



8.5.5 lbs. i>otassiuni chlorid 



In hillsrs. broadcasting: 



Potiussiuin sulphate ap7)lied in hill 



Potassium sulphate applied broadcast 



Potassium chlorid applied in hill 



Potassium chlorid applied broadcast 



2.04 

 1.89 

 1.84 

 1.81 



1.70 

 1.51 

 1.41 

 1.33 



1.72 

 1.81 

 1.14 

 1.42 



4.43 

 3.66 

 3.04 

 2. 52 



2. 29 

 1.91 

 1.48 

 1.48 



2.37 

 1.91 

 1.82 

 1.24 



