Sulfur and Nitrogen Requirements of Sugarcane1
- R. L. Fox2
The internal S requirement of sugarcane (Saccharum officinarum L.) is not well defined and there are no published data on the external SO4-S requirements. The objectives of this study was to provide this kind of information, and to provide data on sulfur distribution and N:S ratios in sugarcane.
Sugarcane was grown in solution cultures and in potted soil material which provided several concentrations and ratios of NO3 and SO4 in solution. External S and N requirements were estimated from plots of yield vs. SO4 or NO3 concentrations in solution cultures and in artificial soil solutions. The external S requirement at age 35 days was about 9 ppm. After 70 days the requirement was about 5 ppm when N was adequately supplied. The external NO3 requirement was about 50 ppm N. The internal S requirement for early growth was 0.36% S in the whole plant and 0.24% for leaf blades 3 through 6. When plants were 70 days old, 0.10% S in leaf blades or 0.08%, S in leaf sheaths was sufficient. Sulfur-deficient, field-grown sugarcane 18 months old contained 0.075% S in leaves 3 through 6 and 0.072% S in the corresponding leaf sheaths. Sulfur fertilized sugar cane contained 0.138% and 0.232% for the same tissues. Ratios N:S differed for various tissues of the same plant. Distribution of S in the plant may be a valuable tool for assessing the S status of sugarcane. When S is deficient, old leaf blades contain more S than corresponding leaf sheaths, and blades and sheaths of leaves 3 to 6 contain about equal concentrations of S. Good S nutrition was associated with an elevated concentration of S in leaf sheaths as compared with leaf blades.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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