20 



Journal of Agricultural Research 



Vol. V, No. 



In sand the limit of growth in the presence of sulphates is shown by 

 figure lo to be less than 10,000 p. p. m., while in the loam growth 

 was scarcely retarded at this concentration. Plants seem able to resist 

 decidedly more magnesium sulphate than either potassium sulphate or 



K2C0, 



(w^co. 



,N<^CO, 



loooppm.' '^^i zfiooppm. 3.oooppm. Aoooppm. 



Check^NoSalt 



s.oooppn. 



6.oooppm. 

 = One plant. 



xoooppm. e.oooppm 



— = 0.1 gm. dry matter. 



lo.ooopptn. 



Fig. II.— Diagram showing the number of wheat plants up and dry matter produced in 14 days on coarse 

 sand with ammonium carbonate, sodium carbonate, and potassium carbonate in different combinations 

 and concentrations. 



ioooppm. 



Aoooppm. 



^.oooppm. 

 , = One plant. 



lOooppm. e.oooppm. noooppn. lo.oooppm. 



= 0.1 gm. dry matter. 



Fig. 12. — Diagram showing the number of wheat plants up and dry matter produced in 16 days on College 

 loam with sodium sulphate, sodium carbonate, and sodium chlorid in different combinations and 

 concentrations. 



sodium sulphate. This is in accord with the earlier results found in 191 2 

 and 1913. 



Figure 1 1 shows that there was no germination whatever in sand where 

 even as little as i ,000 p. p. m. of ammonium sulphate were found. With 



