Submitted to: Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/1997
Publication Date: N/A
Interpretive Summary: Florida legislation aimed at sustaining the natural Everglades requires major reductions in phosphorus content of Everglades Agricultural Area (EAA) drainage waters. The 144,000 ha of sugarcane comprise the major farming activity in the 280,000 ha EAA. Best management practices (BMPs) to reduce phosphorus content of drainage water cost farmers about $153 per ha to implement and $9 per ha to maintain. In addition, legislation has authorized the purchase of 16,000 ha whose use will be converted from farming to phosphorus removal. The first 1,515 ha of this land are now removing 13.5 kg phosphorus per ha each year. This research sought to determine if some sugarcane varieties remove more phosphorus from the soil than others. Results showed that commercial sugarcane varieties may already differ by about 3.7 kg per ha in phosphorus removal. This means that basin wide, choice of sugarcane variety could already account for up to 532,800 kg of phosphorus per year. Genetic enhancement would be expected to improve this. Fruition of the long-term research identified by this preliminary research could supply farmers with a low cost BMP that could contribute substantially to sustaining the natural Everglades and the productive agriculture of the EAA.
Technical Abstract: The phosphorus content of drainage water of the Everglades Agricultural Area (EAA) of Florida must be reduced by at least 25% from a baseline mean calculated using 1978 through 1988 data. At least this amount of P reduction may be one of several steps necessary to sustain much of the unique habitat of remaining natural regions of the Everglades. The objectives of this study were to evaluate variability in leaf tissue P concentration among elite sugarcane (interspecific hybrids of Saccharum spp.) clones and to recommend sampling strategies to detect differences among clones. Samples were collected from three fields four times per annual crop in the plant-cane and first-ratoon crops. Leaf P of sugarcane should be tested at several locations in at least two crop years, and at least once, but preferably twice per crop. It was estimated that clones differed by 5.9 kg per ha in P uptake. Genetic improvement of this trait could be feasible. If further studies show that differences in leaf P concentration can reliably predict differences in total P removal from a sugarcane field, then classification of cultivars for leaf P concentration could make available to EAA sugarcane farmers an additional best management practice (BMP) to reduce P content of their drainage waters.