Cultivar Dependent Sugarcane Response to Nitrogen1
- G. J. Gascho,
- D. L. Anderson and
- H. Y. Ozaki2
Sugarcane (a complex trispecies of Saccharum) in Florida is moving from N-rich Histosols to N-deficient sands. Since little is known about the N-use efficiency of cultivars grown in the continental United States, we conducted studies with four cultivars to compare N-use efficiencies under varying N levels. Three of the cultivars were originally selected as commercial cultivars from the breeding program conducted on N-rich Histosols of the Everglades while the fourth (CP 65-357) was selected from N-deficient soils in Louisiana. A greenhouse experiment, conducted in nutriculture solutions with three N concentrations (0.1, 1.0, and 10.0 mmol L−1) indicated that the highest dry weights were obtained at the second N level from CP 65-357. However, CP 65-357 did not accumulate more N than the other cultivars, suggesting more efficient utilization of accumulated N. The field study was conducted for 2 yr on a complex of Pompano (Typic Psammaquants) and Myakka (Aerie Haplaquod) fine sands of low-N status. Nitrogen levels applied to the first crop were 0, 56, 112, and 224 kg ha−1. The cultivar CP 65-357 gave the highest yields of cane and sucrose, had the highest external and internal N-use efficiencies (kg yield kg−1 applied N and kg yield kg−1 N accumulated in above ground plant parts, respectively) regardless of N rate or year. In the ratoon crop, the external and internal N-use efficiencies for sucrose yield were 24 and 110 kg kg−1, respectively, for CP 65-357 over all N rates, and 7 and 44 kg kg−1, respectively, for CP 63-588, the least N-efficient but the most widely grown cultivar on Histosols in Florida during the period 1975 to 1981. The results suggest that N-use efficiency of sugarcane can be enhanced by selection under low-N conditions.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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