35 



SUMMARY. 



In summarizing these data reference should again be made to 

 the analyses of the soils themselves. Analyses of the two fields used 

 at Cairo in Mr. Roddenbery's experiments, and also a general review 

 of the character of the soils collected from different parts of the State 

 where sugar cane is grown, have been published in previous reports. 

 The average composition of the soil and subsoil of the experimental 

 plats of 1904 is shown in the following table : b 



TABLK IX. Average analyses of soil from fields A and B, experimental plats, Cairo, Ga., 1904- 



It appears that these soils are even poorer than the average south 

 Georgia soils, for, according to the data given in Bulletin No. 70, c 

 it") samples of soil examined contained on an average 92.24 per cent of 

 insoluble matter; 12 samples contained an average of 0.173 per cent 

 of potash, the remainder carrying only traces; 53 samples averaged 

 n.n.~>s per cent of phosphoric acid, and the 65 samples carried an 

 average of 0.058 per cent of nitrogen. 



These data show that the soils on which the sugar canes are grown 

 in ( ieorgia are essentially silicious. They contain altogether, includ- 

 ing combined moisture in the air-dry state, less than 10 per cent of 

 materials not sand. The elements commonly known as essential plant 

 foods, namely, potash, phosphoric acid, and nitrogen, are present in 

 extremely small quantities; and in large numbers of the soils of the 

 State the potash appears only as a trace, being evidently the least 

 abundant of the necessary elements. It is fortunate that in a soil of 

 this kind its sandy nature prevents its becoming packed, and there- 

 fore there is less opposition to the spread of the root systems than 

 in a heavy compact soil. The plant, therefore, can gather quantities 

 of food from the exceedingly small stores present. Nevertheless, it 

 is evident that, for remunerative agriculture, soils of this kind must 

 be fed, and well fed, each year. The modern methods of farming, 

 including the cultivation of green crops for manuring purposes, will 

 do much to improve this soil and increase its content of humus which 

 may serve to hold or store plant foods for future use. Especially 

 is this true of nitrogen which may be grown in green, leguminous 



a Bui. No. 70, p. 11; Bui. No. 93, p. 40. 6 Bui. No. 93, p. 42. c Pages 16-18. 





