CHAPTER 



I O Environmental Influ- 

 ences on the Growth of 

 Sugar Cane 



HARRY F. CLEMENTS 



G 



ood yields of sugar from cane grown in Hawaii range 

 from as little as 6 tons of sugar per acre to more than 18 tons per acre 

 per two-year cycle. Sugar cane is grown at elevations ranging from sea 

 level on up to 2000 feet. It is produced in areas where rainfall varies 

 from a few inches to 200 inches per year. About half of it is irrigated. 

 It is grown on practically level land and on steep slopes facing all direc- 

 tions of the compass, in hot areas and in cool areas, in bright sunny 

 areas and in cloudy areas. It is produced on soils ranging from residual 

 clay soils to alluvial soils made up of coral, coral sand, and clay. 



It is not surprising, therefore, that yields should vary a great deal. 

 It is another matter to determine the factors which cause the extreme 

 variation and to measure the relative influence which each of the sev- 

 eral factors has on the production of sugar. Early in my studies at the 

 University of Hawaii (/), I grew cane in two different areas — one on 

 cloudy windward Oahu, the other on the sunny leeward. The yields 

 were strikingly different. On the cloudy side about half as much cane 

 was produced as on the other side. In order to evaluate the soil influ- 

 ence, soil was taken from the cloudy area to the sunny area and placed 

 in large concrete pots alongside of other pots filled with soil from the 

 sunny area. Cane was planted and the necessary fertilizers applied 

 equally to the pots. After a while it became apparent that the cane grew 

 equally well in both soils. In fact, what small differences existed favored 

 the soil taken from the cloudy area where normally it produced about 

 half as much plant growth as the other soil under its sunny conditions. 



