Submitted to: Soil and Water Conservation Society Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 10, 2008
Publication Date: N/A
Technical Abstract: Biomass from urban landscapes is an untapped resource. Lawn thatch and clippings, fallen leaves and tree limbs are all potential sources of biofuels. Most cities already collect and transport these materials to disposal sites; but, alternatively could collect and transport these materials to a local biomass conversion plant. In 2007, an experiment was begun to evaluate the biomass potential from a typical urban home in Woodward, OK and to estimate the potential biomass yield for the City of Woodward. The lawn was thatched and fertilized with 13-13-13 (N-P-K) fertilizer at the rate 10 lbs bulk material per 1000 ft2 on 15 April. Mowing began on 18 May and every 10-14 days thereafter. The lawn yield potential was estimated by harvesting four 166 square feet areas. The harvested material was weighed fresh, a 0.3-0.5 lb subsample collected and dried, and percentage dry matter determined. The total DM of each sample was calculated by multiplying the percentage DM of the oven-dried sample by the harvested green weight of the sample. In addition, fallen leaves, tree limbs, tree limbs from pruning operations, and tree removal were recorded, weighed and converted to DM and added to the lawn estimates for total annual biomass potential. Estimates for 15 April-22 September shows that a lawn could yield 1,157 lbs of DM (equivalent to 5.3 tons/acre). Of this yield, 500 lbs were carbon and 38 lbs were nitrogen. It was also estimated that 4,100 tons of biomass could be collected annually from the City of Woodward, if every homeowner collected their lawn clippings. If additional components, like fallen leaves, tree limbs, tree limbs from pruning operations, and tree removal, are added to the biomass total about 1,900 lbs (8.7 tons/acre) of DM would be available for alternative energy. The City of Woodward could produce an estimated 6,790 tons of annual biomass DM containing 2,995 tons of carbon and 169 tons of nitrogen. Utilizing biomass from urban landscapes could significantly contribute to the nation’s renewable energy needs.