This component of the Conservation Innovation Grants Summer Burning project evaluates the economic feasibility of using prescribed fire that exceeds the current Natural Resource Conservation Service (NRCS) technical standards as a rangeland restoration practice on privately owned land in Texas. This study has four objectives: (1) Evaluate the economic effectiveness of using prescribed extreme burns as a rangeland restoration tool compared to other rangeland restoration strategies. (2) Provide economic research results that will facilitate a review of the technical standards, specification, and potential policy changes by the NRCS with respect to the use of prescribed extreme burning. (3) Assess economic effects of extreme fire when used in combination with other treatment practices over a 20 year planning horizon. (4) Through modeling, forecasting, and simulation assess the risk associated with the use of extreme prescribed fire, with respect to weather (rainfall) conditions. The research covers four contiguous counties in each of three eco-regions in Texas: Rolling Plains, Edwards Plateau, and the South Texas Plains. Focus group meetings with landowners and NRCS/Extension personnel were held in each region to obtain preliminary information including common rangeland uses, most problematic invasive brush species, and the most commonly used treatment methods and associated costs. The primary invasive species in each region include: Rolling Plains – Prickly Pear (Opuntia phaecantha); Edwards Plateau – Redberry and Ashe Juniper (Juniperus ashei Buchh. And J. pinchotii Sudw., respectively); South Texas Plains – Huisache (Acacia smallii Isely). Mesquite (Prosopis glandulsa Torr.) was identified as a common invasive brush species across all three regions. When extreme fire was compared to the most commonly used invasive brush treatments, assuming the treatment was instituted in year one, it was economically superior in all cases and feasible (Net Present Value > 0 and Benefit/Cost Ratio >1) in all but two cases. The inclusion of forecasted rainfall figures with the combination of using the most commonly used brush treatment with extreme fire proved to substantially reduce the risk of instituting the treatment regimes. The probability distribution of NPVs was significantly smaller when treatment practices were spread over ten years and parcels than when treatment was restricted to the first year and whole ranch.

Thermal gasification of biomass is being considered as one of the most promising technologies for converting biomass into gaseous fuel. Here we present results of gasification, using an adiabatic bed gasifier with air, steam as gasification medium, of mesquite and juniper. From Thermo-gravimetric analyses the pre-exponential factor (B) and activation energy of fuels for pyrolysis were obtained using single reaction models (SRM) and parallel reaction model (PRM). The single reaction model including convention Arrhenius (SRM-CA) and maximum volatile release rate model (SRM-MVR). The parallel reaction model fits the experimental data very well, followed by MVR. The CA model the least accurate model. The activation energies obtained from PRM are around 161,000 kJ/kmol and 158,000 kJ/kmol for juniper and mesquite fuels, respectively. And, the activation energies obtained from MVR are around100,000 kJ/kmol and 85,000 kJ/kmol for juniper and mesquite fuels, respectively. The effects of equivalence ratio (ER), particle size, and moisture content on the temperature profile, gas composition, tar yield, and higher heating value (HHV) were investigated. For air gasification, when moisture increased from 6% to 12% and ER decreased from 4.2 to 2.7, the mole composition of the dry product gas for mesquite varied as follow: 18-30% CO, 2-5% H2, 1-1.5% CH4, 0.4-0.6% C2H6, 52-64% N2, and 10-12% CO2. The tar yield shows peak value (150 g/Nm^3) with change in moisture content between 6-24%. The tar collected from the gasification process included light tar and heavy tar. The main composition of the light tar was moisture. The chemical properties of heavy tar were determined. For air-steam gasification, H2 rich mixture gas was produced. The HHV of the mesquite gas increased first when S: F ratio increased from 0.15 to 0.3 and when the S: F ratio increased to 0.45, HHV of the gas decreased. Mesquite was blended with the Wyoming Powder River Basin (PRB) coal with ratio of 90:10 and 80:20 in order to increase the Tpeak and HHV. It was found that the Tpeak increased with the increase of PRB coal weight percentage (0% to 20%).

This component of the Conservation Innovation Grants Summer Burning project evaluates the economic feasibility of using prescribed fire that exceeds the current Natural Resource Conservation Service (NRCS) technical standards as a rangeland restoration practice on privately owned land in Texas. This study has four objectives: (1) Evaluate the economic effectiveness of using prescribed extreme burns as a rangeland restoration tool compared to other rangeland restoration strategies. (2) Provide economic research results that will facilitate a review of the technical standards, specification, and potential policy changes by the NRCS with respect to the use of prescribed extreme burning. (3) Assess economic effects of extreme fire when used in combination with other treatment practices over a 20 year planning horizon. (4) Through modeling, forecasting, and simulation assess the risk associated with the use of extreme prescribed fire, with respect to weather (rainfall) conditions. The research covers four contiguous counties in each of three eco-regions in Texas: Rolling Plains, Edwards Plateau, and the South Texas Plains. Focus group meetings with landowners and NRCS/Extension personnel were held in each region to obtain preliminary information including common rangeland uses, most problematic invasive brush species, and the most commonly used treatment methods and associated costs. The primary invasive species in each region include: Rolling Plains – Prickly Pear (Opuntia phaecantha); Edwards Plateau – Redberry and Ashe Juniper (Juniperus ashei Buchh. And J. pinchotii Sudw., respectively); South Texas Plains – Huisache (Acacia smallii Isely). Mesquite (Prosopis glandulsa Torr.) was identified as a common invasive brush species across all three regions. When extreme fire was compared to the most commonly used invasive brush treatments, assuming the treatment was instituted in year one, it was economically superior in all cases and feasible (Net Present Value > 0 and Benefit/Cost Ratio >1) in all but two cases. The inclusion of forecasted rainfall figures with the combination of using the most commonly used brush treatment with extreme fire proved to substantially reduce the risk of instituting the treatment regimes. The probability distribution of NPVs was significantly smaller when treatment practices were spread over ten years and parcels than when treatment was restricted to the first year and whole ranch.

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Sustainable Built Environments Senior Capstone / The mesquite-harvesting project at the University of Arizona was in practice from 2011-2013. During the development of the project, students, faculty, and staff were engaged in harvesting, designing harvesting methods, milling, baking, researching, and selling mesquite flour at the campus. After discovering a common toxin in mesquite-pods, a strict harvesting method was obtained and followed throughout the seasons. However, because of the high-maintenance process of harvesting, the mesquite-harvesting project at the University of Arizona could not economically sustain on campus, and therefore, had to come to an end. This document explains the process of harvesting, the research of aflatoxin, best practices, and other events that happened during the UA mesquite-harvesting project.

A native desert Rhizobium, AZ-M1, was isolated from a nodulated mesquite tree (Prosopis juliflora var. velutina) following inoculation of mesquite seed with a desert soil. This strain and a selected commercial strain (31A5) were used in a greenhouse study to determine their N fixation efficiency against applied N fertilizer. Strain AZ-M1 was a more efficient N fixer than 31A5. The survival rate of the two strains was tested in three different desert soils in a controlled laboratory study. The native strain AZ-M1 grew and survived in the soils over a period of one month. The commercial strain did not grow and the population decreased from 10⁸ cells gm⁻¹ of dry soil to below 10⁴ cells after 14 days. Soil factors affected survival of both strains. The competitiveness of the two strains was compared in a greenhouse experiment. The native isolate out competed strain 31A5 in nodule occupancy regardless of cell number when applied as a mixed inoculant. A high incidence of double occupancy was found in the root nodules when double strain inoculants were applied. The two rhizobia were fast growing rhizobia, lowering the pH of a defined medium. Strain AZ-M1 showed a high intrinsic resistance to 3 antibiotics among 12 tested. Strain AZ-M1 has been shown to be highly effective, fairly competitive and survive better in desert soils than strain 31A5.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Bacterial cellulose (BC) is a naturally nanoscale biomaterial with high purity and excellent chemical and mechanical properties. There are several sugar-rich renewable sources and wastes that can be used as alternative media for bacterial cellulose production.The aim of this study was to evaluate the suitability of an extract of mesquite pods as an alternative carbohydrate source for the production of BC through fermentation by Gluconacetobacter hansenii. The amount of sugars, soluble solids, and pH of the extract was characterized. The influence of the initial sugar concentration, pH, and the source of supplementary nitrogen on the fermentation were evaluated. The best production of bacterial cellulose was achieved in the medium with a sugar concentration of 30 g /L, pH 4.0, and supplemented with 10 g /L of yeast extract. The films from the optimized medium were oven dried and characterized by x-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and electron microscopy (SEM). The results were similar to typical bacterial cellulose films produced in the reference medium HS. Thus, it was possible to demonstrate the suitability of mesquite pod aqueous extract to produce BC. / A celulose bacteriana (CB) à um biomaterial naturalmente nanomÃtrico, com elevado grau de pureza e excelentes propriedades quÃmicas e mecÃnicas. Existem na natureza fontes renovÃveis e resÃduos ricos em aÃÃcares que despertam um crescente interesse como meios alternativos em substituiÃÃo aos tradicionalmente empregados na produÃÃo de celulose. O objetivo deste estudo foi avaliar o extrato de vagens de algaroba (Prosopis juliflora) como fonte alternativa para produÃÃo de CB atravÃs de fermentaÃÃo por Gluconacetobacter hansenii. O extrato foi caracterizado quanto à quantidade de aÃÃcares, pH e sÃlidos solÃveis. AtravÃs da fermentaÃÃo do extrato foram realizados testes de influÃncia da concentraÃÃo inicial de aÃÃcares, influÃncia do pH e efeito da variaÃÃo da suplementaÃÃo com fonte de nitrogÃnio sobre a produÃÃo de CB. A melhor produÃÃo foi proveniente da fermentaÃÃo do extrato de algaroba diluÃdo a uma concentraÃÃo de aÃÃcares de 30 g/L com pH 4,0 suplementado com 10 g/L de extrato de levedura. As pelÃculas obtidas do extrato com condiÃÃes melhoradas foram secas em estufa e caracterizadas por difraÃÃo de raios x (DRX), espectroscopia de absorÃÃo no infravermelho (FTIR), anÃlise termogravimÃtrica (TGA), calorimetria exploratÃria diferencial (DSC) e microscopia eletrÃnica de varredura (MEV), e apresentaram resultados tÃpicos de celulose bacteriana quando comparados à CB produzida no meio de referÃncia HS. Assim, foi possÃvel mostrar a viabilidade de produÃÃo de CB com extrato aquoso de vagens de algaroba.