|Holtkamp, M. - SWFWMD- SWIM, TAMPA, FL.|
Submitted to: Environmental Science and Pollution Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 6, 2004
Publication Date: November 1, 2004
Citation: Sigua, G.C., Holtkamp, M.L., Coleman, S.W. 2004. Assessing the efficacy of dredged materials from Lake Panasoffkee, Florida: Implication to environment and agriculture. Part 2-Pasture establishment and forage quality. ESPR Environmental Science and Pollution Research. 11(6):394-399. Interpretive Summary: Bahiagrass is the most important pasture grass in Florida and much of the Gulf Coast region of the U.S. Establishment is often slower than desired due to poor nutrient availability from sandy soils. Establishment of an excellent, uniform stand of bahiagrass in a short time period is important. Failure to obtain an established stand means the loss of not only the initial investment costs, but also production and its cash value. Forage production often requires significant inputs of lime and N fertilizer. This study was initiated to: (1) assess the value of lake dredged materials as a soil amendment to establish bahiagrass in a subtropical beef cattle pasture in Sumter County, Florida; and (2) determine the effect of lake dredged materials application on the crude protein and uptake of nutrient by bahiagrass. The experimental treatments that were evaluated consisted of different proportions of lake dredged materials at 0, 25, 50, 75, and 100%. We demonstrated that bahiagrass in plots had significantly higher forage yield and crude protein content when compared with those bahiagrass in the control plots. Land application of lake dredged materials may provide substantial benefits that will enhance the environment, community, and society. As such, the agricultural or livestock industry could utilize these lake dredged materials to produce forages. Lake dredged materials should be regarded as a beneficial resource, as a part of the ecological system.
Technical Abstract: Current dredged material disposal alternatives have several limitations. Options for dealing with dredged materials include leaving them alone, capping them with clean sediments, placing them in confined facilities, disposing of them at upland sites, treating them chemically, or using them for wetlands creation or other beneficial uses The ability to reuse lake-dredge materials (LDM) for agricultural purposes is important because it reduces the need for offshore disposal and provides an alternative to disposal of the materials in landfills. Often these materials can be obtained at little or no cost to the farmers or landowners. Thus, forage production offers an alternative to waste management since nutrients in the LDM are recycled into crops that are not directly consumed by humans. The objective of this study (Part 2) were to: (1) assess LDM as a soil amendment to establish bahiagrass (BG) in a subtropical beef cattle pasture in Sumter County, Florida; and (2) determine the effect of LDM application on the crude protein (CP) and nutrient uptake of BG. The experimental treatments that were evaluated consisted of different ratios of natural soil (NS) to LDM: LDM0 (100% NS:0% LDM); LDM25 (75% NS:25% LDM); LDM50 (50% NS:50% LDM); LDM75 (25% NS:75% LDM); and LDM100 (0% NS:100% LDM). Bahiagrass plots at its early establishment were cut to a 5-cm stubble height on Julian days 112 and harvested to the same stubble height on Julian days 238 and on Julian days 546 following the double-ring method. Results showed consistently and significantly (p ' 0.001) higher BG biomass production and CP from plots amended with LDM than those of BG planted on plots with 0% LDM. Forage yield of BG during its establishment increased quadratically (Forage Yield = -371.2+1887.8*LDM'207.8*LDM2; R2 = 0.95; p < 0.0001) with increasing rates of LDM application. The CP of BG also varied significantly with varying levels of LDM applications. The tissues of BG with 100% LDM had the greatest CP content while the lowest CP content was from the control plots (LDM0). The CP of BG increased linearly with increasing rates of LDM application. The crude protein response to BG application was also described by a quadratic equation: Crude Protein = 6.2+3.75*LDM'0.41*LDM2; R2 = 0.96; p < 0.0001.