SUSTAINABLE NUTRIENT MANAGEMENT PACKAGE FOR COST-EFFECTIVE BIOENERGY BIOMASS PRODUCTION |
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Authors: | Sampson Agyin-Birikorang George A O’Connor John E Erickson |
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Institution: | 1. International Fertilizer Development Center (IFDC) , Muscle Shoals , Alamaba , USA;2. Soil and Water Science Department, University of Florida , Gainesville , Florida , USA;3. Agronomy Department, University of Florida , Gainesville , Florida , USA |
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Abstract: | Commercial fertilizer (particularly nitrogen) costs account for a substantial portion of the total production costs of cellulosic biomass and can be a major obstacle to biofuel production. In a series of greenhouse studies, we evaluated the feasibility of co-applying Gibberellins (GA) and reduced nitrogen (N) rates to produce a bioenergy crop less expensively. In a preliminary study, we determined the minimum combined application rates of GA and N required for efficient biomass (sweet sorghum, Sorghum bicolor) production. Co-application of 75 kg ha?1 (one-half of the recommended N rate for sorghum) and a modest GA rate of 3 g ha?1 optimized dry matter yield (DMY) and N and phosphorus (P) uptake efficiencies, resulting in a reduction of N and P leaching. Organic nutrient sources such as manures and biosolids can be substituted for commercial N fertilizers (and incidentally supply P) to further reduce the cost of nutrient supply for biomass production. Based on the results of the preliminary study, we conducted a second greenhouse study using sweet sorghum as a test bioenergy crop. We co-applied organic sources of N (manure and biosolids) at 75 and 150 kg PAN ha?1 (representing 50 and 100% N rate respectively) with 3 g GA ha?1. In each batch of experiment, the crop was grown for 8 wk on Immokalee fine sand of minimal native fertility. After harvest, sufficient water was applied to soil in each pot to yield ~1.5 L (~0.75 pore volume) of leachate, and analyzed for total N and soluble reactive P (SRP). The reduced (50%) N application rate, together with GA, optimized biomass production. Application of GA at 3 g ha?1, and the organic sources of N at 50% of the recommended N rate, decreased nutrient cost of producing the bioenergy biomass by ~$375 ha?1 (>90% of total nutrient cost), and could reduce offsite N and P losses from vulnerable soils. |
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Keywords: | gibberellins manure biosolids N and P uptake leaching losses dry matter yield sweet sorghum |
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