Person: Wechsung, Gabriele
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Veröffentlichung Data from the Arizona FACE (Free-Air CO2 Enrichment) Experiments on Wheat at Ample and Limiting Levels of Water and Nitrogen(2017) Kimball, Bruce Arnold; Pinter Jr., Paul J.; LaMorte, Robert L.; Wechsung, GabrieleFour free-air CO2 enrichment (FACE) experiments were conducted on wheat (Triticum aestivum L. cv. Yecora Rojo) at Maricopa, Arizona, U.S.A. from December, 1992 through May, 1997. The first two were conducted at ample and limited (50% of ample) supplies of water, and second two at ample (350 kg N ha-1) and limited (70 and 15 kg N ha-1) supplies of fertilizer nitrogen. More than 50 scientists participated, and they collected a large and varied set of data on plant, soil, and microclimatic responses to the elevated CO2 and its interactions with the water and N treatments. The dataset has been popular with wheat growth modelers who have utilized the growth, yield, and other data to validate their models, which get used to predict likely future wheat productivity with projected global change. The dataset assembled herein contains many of these data, including management, soils, weather, physiology, phenology, biomass growth, leaf area, yield, quality, canopy temperatures, energy balance, soil moisture, nitrogen assimilation, and other data. Quelle: VerlagsinformationVeröffentlichung Nitrogen soil surface budgets for districts in Germany 1995 to 2017(2020) Häußermann, Uwe; Klement, Laura; Breuer, Lutz; Ullrich, Antje; Wechsung, GabrieleBackground Nitrogen (N) as a key input for crop production has adverse effects on the environment through emissions of reactive nitrogen. Less than 20% of the fertiliser nitrogen applied to agricultural land is actually consumed by humans in meat. Given this situation, nitrogen budgets have been introduced to quantify potential losses into the environment, to raise awareness in nutrient management, and to enforce and monitor nutrient mitigation measures. The surplus of the N soil surface budget has been used for many years for the assessment of potentially water pollution with nitrate from agriculture. Results For the 402 districts in Germany, nitrogen soil surface budgets were calculated for the time series 1995 to 2017. For the first time, biogas production in agriculture and the transfer of manure between districts were included in the budget. Averaged for all districts, the recent N supply to the utilised agricultural area (UAA) totals 227 kg N ha-1 UAA (mean 2015-2017), among them 104 kg N ha-1 UAA mineral fertiliser, 59 kg N ha-1 UAA manure, 33 kg N ha-1 UAA digestate, 14 kg N ha-1 UAA from gross atmospheric deposition, 13 kg N ha-1 UAA biological N fixation, and 1 kg N ha-1 UAA from seed and planting material. The withdrawal with harvested products accounts for 149 kg N ha-1 UAA, resulting in an N soil surface budget surplus of 77 kg N ha-1 UAA. The N surpluses per district (mean 2015-2017) vary considerably between 26 and 162 kg N ha-1 UAA and the nitrogen use efficiency of crop production ranges from 0.53 to 0.79 in the districts. The N surplus in Germany as a whole has remained nearly constant since 1995, but the regional distribution has changed significantly. The N surplus has decreased in the arable farming regions, but increased in the districts with high livestock density. Some of this surplus, however, is relocated to other districts through the transfer of manure. Conclusions The 23-year time series forms a reliable basis for further interpretation of N soil surface surplus in Germany. Agri-environmental programmes such as the limitation of the N surplus through the Fertiliser Ordinance and the promotion of biogas production have a clear effect on the N surplus in Germany as a whole and its regional distribution. © 2020 BioMed Central Ltd.