Oct. i, 1920 



Cause of Lime-Induced Chlorosis 



5i 



may be called "ferric molasses" was also used. This was prepared by 

 boiling together 2 parts of ferrous sulphate and 10 parts of a final molasses. 

 It doubtless contained some ferric acetate, glucolate, laevulate, possibly 

 other organic iron compounds, and considerable inorganic iron. As a 

 control on the action of the "ferric molasses," the same quantity of 

 molasses which had been similarly boiled without addition of iron was 

 applied to two other lots of pots. To one of these lots ferrous sulphate 

 was applied after the boiled molasses had been mixed with the soil in 

 the pots designated as "molasses and ferrous sulphate" in Table XI. 



Five rice plants were grown in each pot from September 28 to Decem- 

 ber 28, 1 91 4. In the noncalcareous series each pot contained 14 pounds 

 of loamy soil with the moisture content maintained at 23 per cent of the 

 dry weight; and in the calcareous series each pot contained 14 pounds of 

 loamy soil with the moisture content maintained at 27 per cent of the dry 

 weight. The calcareous soil contained 17.8 per cent of carbonate of lime. 

 A fertilizer consisting of 1.8 gm. ammonium nitrate, 4.2 gm. sodium nitrate, 

 3 gm. ammonium sulphate, 0.4 gm. acid potassium phosphate, 3.9 gm. 

 acid phosphate, and 3.8 gm. potassium sulphate was added to each pot 

 in four applications. The molasses and all the iron compounds were 

 mixed with the soil before the rice was planted. The iron was applied 

 at the rate of 0.25 gm. and the molasses at the rate of 6.25 gm. per pot. 

 The results of the experiment are summarized in Table XI. 



Table XI. — Comparative availability to rice plants of organic and inorganic compounds 

 of iron in a calcareous and noncalcareous soil: Experiment VIII 



Special additions to the 

 soil. 



Oven-dried yield of plants per pot. 



Calcareous soil. 



Series Series 

 A. B. 



Series 

 C 



Series 

 D. 



Series 

 E. 



Aver- 

 age. 



Noncalcareous soil. 



Series 

 A. 



Series 

 B. 



Series 

 C 



Series 

 D 



Series 

 E. 



Aver- 

 age. 



Ferric chlorid 



Ferric tartrate 



Ferric citrate 



Ferric valerianate 



Ferric benzoate 



Molasses 



" Ferric molasses " 



Molasses and ferrous sul- 

 phate 



Ferrous sulphate 



Gm. 



20 



16 

 12 

 18 



Gm. 



16 



Gm. 



Gm. 



Gm. 



13 



Gm. 



13 

 19 

 IS 



Gm. 

 39 



Gm. 



41 



Gm. 

 38 



Gm. 



4i 



Gm. 



Gm 



Three weeks after planting, all plants in the noncalcareous soil were 

 green, while many plants in the calcareous soil were slightly chlorotic. 

 Those plants in the calcareous soil which received molasses alone or 

 molasses with ferrous sulphate were markedly chlorotic (PI. 6, B) . During 

 later growth the plants in noncalcareous soil remained green and those 

 in calcareous soil became more chlorotic, some plants eventually dying 

 from the top down. 



