MANURE, YIELD AND SOLUBLE SALTS IN SOILS. 



53 



INFLUENCE OF MANURE UPON THE AMOUNTS OF POTASH RECOV- 

 ERED FROM SOILS BY PLANTS. 



If we combine the data in the table, making two groups, 

 under the stronger and poorer soils, they will stand as next 

 given : 



Mean amounts of potash recovered from corn and potatoes growing 

 upon manured and unmanured ground. 



It is thus shown that the crops on the manured ground have 

 recovered 29 per cent, more potash from the four stronger soils 

 and forty per cent, more from the four poorer soils, where the 

 15 tons of manure had been applied. Associated with these 

 differences in the amounts of potash recovered by the plants 

 there have been the following differences in yield of water-free 

 dry matter in shelled corn and potatoes, using 21.1 per cent, as 

 the estimated amount of dry matter in the tubers as a basis 

 for calculating the dry matter produced in this crop : 



Mean amounts of dry matter produced by corn and potatoes on 

 manured and unmanured ground. 



