JOIHAL OF AGKIIDLTim ISEARCH 



DEPARTMENT OF AGRICULTURE 



Vol. V Washington, D. C, November 29, 191 5 No. 9 



ASH COMPOSITION OF UPLAND RICE AT VARIOUS 

 STAGES OF GROWTH 



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INTRODUCTION <-5^^Z-/i. 



By P. L. GiLE, Chemist, and J. O. CarreRO, Assistant Chemist, Porto Rico Agricultural 

 Experiment Station 



The following ash analyses of upland rice (Oryza saliva) at various 

 stages of growth were made in connection with a study of the effect of 

 lime-induced chlorosis on the ash composition of the plant. In the course 

 of this work it was necessary to know particularly how the iron content 

 of the plant varied with its age. The analyses are reported here, as it 

 is beUeved that such data are of general importance in explaining cer- 

 tain peculiarities of crop growth. 



Kelley and Thompson ^ have already investigated the composition of 

 rice at different stages of growth, but their study did not suffice for our 

 purpose, as it covered only the last half or third of the growing period 

 and did not include iron and some other ash constituents. 



EXPERIMENTAL METHODS EMPLOYED 



The plants were grown in large cylinders sunk in the ground and 

 protected by wire netting (4 meshes to the inch) . Each cylinder afforded 

 a surface of 7 square feet of soil in which 29 plants were grown. 



Porto Rican red-clay soil, which is well adapted for rice, was used in 

 the cylinders. This was fertilized liberally with sulphate of ammonia, 

 acid phosphate, and muriate of potash, so that the ash composition might 

 not be influenced at any stage by a lack of nutrients. Fertilizers furnish- 

 ing ID gm. of nitrogen (N), 5 gm. of phosphoric acid (P2O5) and 10 gm. of 

 potash (K2O) were incorporated with the soil before planting; when the 

 plants were 18 days old, a surface application of 2 gm. of nitrogen, i gm. 

 of phosphoric acid, and 2 gm. of potash was made; and when the plants 

 were 59 days old, 3 gm. of nitrogen, 3 gm. of phosphoric acid, and 3 gm. 

 of potash were applied. 



1 Kelley, W. P., and Thompson, Alice R. A study of the composition of the rice plant. Hawaii Agr. 

 Exp. Sta. Bui. 21, SI p. 1910. 



Journal of Agricultural Research, Vol. V, No. 9 



Dept. of Agriculture, Washington, D. C. Nov. 29, 1915 



az B— 6. 



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