Sugarcane Yield Response to Phosphorus Fertilizer as Related to Extractable Soil Phosphorus on Florida Mineral Soils

ABSTRACT

Relating phosphorus (P) fertilization to crop demand in sugarcane (Saccharum spp.) grown on mineral soils in southern Florida is critical for minimized environmental impact and sustained crop production. Previous P fertilizer recommendations date to 1974 and so revised recommendations are needed for sugarcane on these soils which account for 29% of the crop in Florida. Phosphorus rate studies were conducted at seven field locations (16 total site-crop years) with P rates of 0 to 73 kg P ha⁻¹ at Site 1 and 0 to 61 kg P ha⁻¹ at Sites 2–7 using small-plots (82 or 120 m² plots) on four soil series representing Spodosols, Entisols, and Alfisols. Soil P extractions with Mehlich 3, 0.7 M ammonium acetate, and water were evaluated in relation to relative sucrose yield and leaf P concentrations. Mehlich 3 had stronger relationships with relative yield and leaf P and a Mehlich 3 P value of 80 g m⁻³ is proposed as a critical value above which no P fertilizer would be required. Without added P fertilizer, Mehlich 3-extractable P values decreased annually by an average of 20%. Results suggest maintaining 36.7 kg P ha⁻¹ as the maximum P fertilizer rate for sugarcane in mineral soils.

Abbreviations: EAA: Everglades Agricultural Area; BMPs: best management practices; DAP: diammonium phosphate; MCH: megagram (Mg) cane ha⁻¹; MSH: megagram (Mg) sucrose ha⁻¹; KSM: kg sucrose Mg⁻¹ cane; M3P: Mehlich 3-extractable soil P; AmAcP: ammonium acetate-extractable soil P; Pw: water-extractable soil P

KEYWORDS:

• Soil testing
• nutrient availability
• calibrated soil test
• fertilizer recommendations
• macronutrients
• phosphorus
• soil fertility
• testing methodology
• fertilizers
• plant nutrition

Acknowledgments

The authors would like to thank the following growers for their participation and support of the study: United States Sugar Corporation, Florida Crystals Corporation, A. Duda and Sons, Inc., and Sugar Cane Growers Cooperative of Florida. The study was supported by donations from the Florida Sugar Cane League, Inc.-Sugarcane Industry Research Committee and grant support from the Florida Department of Agriculture and Consumer Services. Fertilizer for all trials was donated by Wedgworth’s, Inc. The authors had no competing interests in relationships with growers or funding agencies.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Florida Department of Agriculture and Consumer Services [UF Project P0027187]; Florida Sugar Cane League.