MICHKJAN ACADEMY OF SCIENCE. 165 



cliemical and biological points of view. These data have appeared in a 

 previous bulletin". In order to find out if any possible benefit could be 

 derived from any addition of salts in definite proportions the soil solu- 

 tions were treated with the 36 different combination of three salts, these 

 three salts being KH0PO4, Ca(NO,,)o, and MgSO^. By this method it 

 would seem to be possible to determine what a particular soil lacks, and 

 what treatment it needs to improve it. Below is reported very briefly 

 the results obtained with a solution extracted fi-om an infertile soil and 

 another solution pressed from a fertile soil. 



To the different soil solutions was added the three salts in the various 

 ratios as described above. As indicators to determine the relative values 

 of the various cultures, seedlings of winter wheat were used. At the 

 same time that the series on the soil solution of the poor soil was run, 

 there was a similar series made up with distilled water for comparison. 

 After about four weeks growth the plants were harvested and the dry 

 weights determined. The data for the dry weight of tops are mentioned 

 here only. Besides these, data were collected on transpiration, water 

 requirement, evaporating power of the air, and dry weight of roots. 

 In the distilled water series the culture solution which gave the highest 

 dry weight was the solution designated as 523. This means that five- 

 tenths of the total concentration was from the KHoPO^, two-tenths from 

 the Ca(N03)o and three-tenths from the ^IgSO^. In the case of the 

 cultures made up with the soil solution the best result was in culture 

 designated as 712 — seven-tenths of the concentration was made up of 

 KH^PO^, one-tenth of Ca(N03)o and two-tenths of MgSO^. By com- 

 paring these two results an interesting fact can be brought to light. 

 Taking 523 as normal it is readily seen, that the soil solution needed 

 more than the five-tenths of KH^PO^. In fact it needed seven-tenths. 

 It follows then that the soil solution lacked K and P0O-. In addition it 

 had abovit the right ratio of Ca and N and about the right amount of 

 Mg and S. A chemical analysis of the original soil solution showed that 

 it was poor in K and PoOj. In regard to the Ca, N, Mg and S the 

 results of the chemical analysis and the needs of the soil did not com- 

 pare so well. It appears that it will be possible in this way to find out 

 the needs of the soil. It is further necessary to grow seedlings in this 

 poor soil to which has been added a certain definite amount of KHoPO^ 

 to supply the lack. If the seedlings do better here than in the soil with- 

 out KHoPO^ treatment it would seem that something of value had been 

 obtained. This work has not yet been completed. The above experiment 

 has been repeated with soil solutions obtained from a good sandy loam 

 soil. The result showed that the best salt proportion was that designated 



"Morgan, J. F. — The soil solution obtained bv the oil pressure method. Soil Science, 

 Vol. Ill, No. (i; .1.Sl-54fi. I'JIT. 



