1,112 research outputs found

    Fertilizer Use by Crop at the Country Level (1990–2010)

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    We compute the fertilizer use in corn, cotton, soybeans, and rapeseed in the period from 1990 to 2010 for a set of selected countries. In each case, we present the consumption of nitrogen, phosphate, and potash by crop and by year, reporting both the fertilizer application rates (in kilograms per hectare) and the fertilizer consumption (in thousand metric tonnes). We allocate a country’s total nutrient consumption in a given year among competing crops based on publicly available statistics. The resulting allocation of fertilizer among crops is a function of the country’s nutrients total use, the country’s cropped areas, crop world prices, and crop- and country-specific fertilizer application rates for some years. In this report we show results on fertilizer consumption by crop for the top fertilizer consuming countries, and a downloadable MS Excel file “FertilizerDemandByCropData.xls” shows the complete set of results

    High temperature treatments of porous activated carbon

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    The use of biomass waste for the preparation of activated carbon is of great industrial interest for reducing costs and increasing the sustainability, especially in the field of energy storage. A high temperature treatment is required to obtain a more ordered carbon material, thus increasing its conductivity. However, this high temperature treatment entails as a disadvantage a significant reduction in porosity. Therefore, a method to prepare activated carbons with a high porosity development as well as high conductivity could be of great interest for many applications. The aim of this work is to analyze the possible influence of phosphorus compounds on the physical-chemical properties of different carbon materials thermally treated at relatively high temperatures (1600 ºC). With this goal, it has been prepared activated carbons from different precursors (olive stone, lignin and hemp) and different conformations (powder, fibers and monoliths) by physical and chemical activation, with CO2 and H3PO4, respectively. Once the different activated carbon materials were prepared, they were thermally treated at 1600 ºC under inert atmosphere. The different samples were characterized by N2 and CO2 adsorption at 77 and 273 K, respectively, XPS, XRD and Raman techniques. The oxidation resistance was also evaluated in a thermogravimetric balance. High temperature treatments of activated carbon without the presence of P surface groups produced an important contraction of the porosity (from 900 to 150 m2 g-1). However, temperature treatments of phosphorus-activated carbon allowed for preparing carbon materials with a relatively high structural order and a well-developed porosity (c.a. 1100 m2 g-1), with a significant contribution of mesoporosity. These results suggest that these P-surface groups are responsible for the low contraction observed for the porous structure, avoiding, in a large extent, its collapse.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. MINECO (CTQ2015-68654-R). MINECO (PTA2015-11464-I)

    A Nonlinear Offset Program to Reduce Nitrous Oxide Emissions Induced by Excessive Nitrogen Application

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    On average, U.S. farmers choose to apply nitrogen fertilizer at a rate that exceeds the ex post agronomically optimal rate. The technology underlying the yield response to nitrogen rewards producers who over apply in years when rainfall is excessive. The overapplication of nutrients has negative environmental consequences because the nitrogen that is not taken up by the plant will typically volatilize causing N2O emissions, or leach causing water pollution. We present a nonlinear offset program that induces farmers to reduce their nitrogen applications to the level that will be consumed by the plant in a typical year and, as a result, reduce N2O emissions from agriculture. The offset program is nonlinear because of the nonlinear relationship between N2O and nitrogen application rates. We assume that the farmer solves an expected utility maximization problem, choosing the optimal nitrogen application rate. The key contribution is a set of simulations that shows that modest offset payments will induce participation in the program and will have a significant impact on both expected and actual N2O emissions without having a significant impact on actual or expected yields. We also find that more risk-averse farmers will reduce emissions by a greater amount than less risk-averse farmers. Finally, we show the distribution of emission reductions induced by this nonlinear offset scheme.nitrogen fertilizer; carbon offsets; nitrous oxide; pollution; uncertainty.
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