Wednesday, November 15, 2006
286-18

Sugarcane Response to DRIS-Based Fertilizer Supplements in Florida.

J. Mabry McCray, Univ of Florida, 3200 E Palm Beach Rd, Belle Glade, FL 33430

Soil testing is a valuable best management practice for Florida sugarcane growers, but soil samples are routinely only taken every 3 to 4 years when a field is replanted because of difficulty in obtaining representative soil samples after banding fertilizers. Leaf analysis is a useful diagnostic tool that can be combined with soil analysis to improve growers’ decisions. This study is being conducted to determine the sugarcane production response to a DRIS (Diagnosis and Recommendation Integrated System)-based fertilizer supplement and to develop guidelines for its economic use. Paired, large-scale commercial fields were compared with and without a fertilizer supplement (applied mid-June to early-July) based on leaf nutrient DRIS indices in leaf samples taken in late April through mid-May (leaf blade of top visible dewlap). Nutrients considered for application were N, P, K, Mg, Fe, Mn, Zn, and Cu. A given nutrient was applied when its DRIS index was <-1 and the rate was increased to a predetermined maximum at index -25. Soluble forms of all nutrients were applied using air or ground equipment as necessary. There were 19 comparisons in 2004/05 (15 organic soils, 4 mineral soils) and 24 comparisons in 2005/06 (17 organic soils, 7 mineral soils). In these first 2 years of the study there have been no significant differences in production of sugarcane/ha or sugar/ha between control fields and fields receiving a DRIS-based supplement. A major problem with each of the last 2 years has been widespread hurricane damage (Sept 2004 and Oct 2005 with production losses of 15-20% each year). This may have limited potential responses to fertilizer supplements and so the experiment needs to be continued at least one more year to determine crop response in a year with relatively good growing conditions.  

Handout (.pdf format, 44.0 kb)

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