I20 



Journal of A gricultural Research voi. xviii, no. 3 



method show the soils as quite acid. That the substances in the soil 

 which react with the potassium nitrate and calcium acetate are not 

 entirely the same is plainly shown in the different acidity results ob- 

 tained by the two methods. Neither soil can be said to contain a normal 

 amount of calcium, and the magnesium of both is more than twice the 

 calcium content. 



Table I- — Analyses of soils used 



Determinations." 



Volatile matter 



Potassium oxid (KjO) 



Calcium oxid (CaO) 



Magnesium oxid (MgO) 



Manganese oxid (Mn304) 



Ferric oxid (FcjOs) 



Aluminum oxid (AI2O3) 



Phosphorus oxid (P2O5) 



Sulphate (SO3) 



Residue 



Nitrogen 



Humus (acid) b 



Humus c 



Hygroscopic moisture 



Acidity: 



Potassium-nitrate method 

 Calcium-acetate method. . 



Water-holding capacity 



« Wiley, H. W. op. cit. 



'' Ammonia soluble without previous washing with dilute hydrochloric acid. 



" Washed with hydrochloric acid, digested with ammonia, filtered, and refiltered till clear. 



<* Pounds of calcium carbonate required to neutralize one million poiuids of soil. 



< Grams of water per loo em. of dry soil. 



GREENHOUSE TESTS 



Pot tests were conducted in duplicate for all treatments on each soil. 

 The crops in the order in which they were grown were wheat, red 

 clover, and blood turnip beets. The containers for the soil were galvan- 

 ized iron pots, 9.25 inches in diameter and 1 1 inches deep, paraffined well 

 on the inside. One-inch galvanized iron tubes, connected with an arch 

 at the bottom of the pot (both well paraffined) , were provided for aeration 

 and the addition of water. The seed was selected with care, planted 

 uniformly, and the resulting plants Vv^ere kept under good conditions for 

 their development. The soil was kept at optimum moisture content by 

 weighing the pots at regular intervals and replenishing the water lost 

 with distilled water. The various soil treatments employed and the 

 crop yields are given in Table II. 



Table II shows that the 4,000-pound applications of calcite, magnesite, 

 and dolomite gave similar results on both soils. The differences between 

 the calcite, magnesite, and dolomite increases were small for the wheat 

 and clover, while the magnesium carbonate gave much larger increases 

 with the beets. 



