110 



It dissolves about the same amount of phosphoric acid from the Kentucky- 

 soil as from the station soil, both of which have a fair amount of available phos- 

 phoric acid, although the former has a much higher total phosphoric acid con- 

 tent. It distinguishes these soils very sharply from the clay soils known to be 

 deficient in phosphoric acid. 



The alkaline ammonium chlorid distinguishes the fertilized from the unfertil- 

 ized plats very sharply on the station soil and to a fair extent on the Kentucky 

 soil. Its action on the clay lands is in accord with what knowledge we have in 

 regard to the potash in these soils. 



The ammonium chlorid dissolved in ammonia, sp. gr. 0.96, gives results on 

 potash in the same general direction as the mildly alkaline ammonium chlorid, 

 but the differences are less sharply defined. As this solution is rather troublesome 

 to work with, I would prefer to use the mildly alkaline one. 



The neutral ammonium chlorid distinguishes very well the Kentucky soil 

 from the station soil, gives fair indications on the clay soils, but fails to show the 

 effect of the potash salts applied to the station soil. 



Ammonium hydrate, sp. gr. 0.96, gives results on potash that are quite at 

 variance with what is known about these soils, but on phosphoric acid it gives 

 promising results. The character of the individual results indicates that the 

 digestion was not continued long enough to complete the reaction. Yet the results 

 clearly distinguished the lands poor in phosphoric acid from those known to be 

 well supplied with available phosphoric acid. The only case where it seems at 

 fault is on plat 1 of the station soil. But every other solvent acts in the same 

 way, indicating that the sample from this plat is really higher in phosphoric acid 

 than the sample from the other blank plat, No. 4. Crop tests covering five years 

 show that plat 1 has a crop-producing capacity about lo per cent, greater than 

 plat 4. 



Ammonium chlorid in neutral and alkaline solution removes notable quan- 

 tities of lime from soils. The quantities were determined and are given in 

 Table III. 



