MANURE, YIELD AND SOLUBLE SALTS IN SOILS. 



59 



ratios which did exist at the time were, approximately, the 

 same as would be shown by the differences in the amounts of 

 dry matter given in the table, p. 53. If calculations are made 

 on the basis of those values it will be found that the absolute 

 -amounts of nitric and phosphoric acids which were recovered 

 from tihe plants are largest from those which had grown upon 

 the manured ground. 



In the case of sulphates recovered from the plants, under the 

 two conditions, there were larger relative amounts recovered 

 from the corn growing upon the manured land, and also from 

 the potatoes in the case of the stronger soils. This relation was, 

 however, reversed in the potatoes from the poorer soils. 



In view of the fact that the soil moisture has usually shown 

 such large amounts of sulphates, when compared with those of 

 other ingredients determined, it appears not a little remark- 

 able that the plant sap should have been found to contain so 

 little. The sulphur is, of course, appropriated as growth goes 

 forward, and possibly the small amounts observed are due to 

 absorption in this way. 



In the case of chlorine, which has invariably been found in 

 these soils in very small amounts, the relations are the reverse 

 so far as the plants are concerned. Not only are relatively large 

 amounts recovered- from the plant tissues, but the differences 

 between the amounts recovered from the plants grown upon the 

 manured and unmanured ground are very large, and in the 

 same direction as occurred in the case of potash. The relations 

 are expressed in the next table: 



Mean amounts of chlorine recovered from corn and potatoes grown 

 upon manured and unmanured ground. 



