Effect of straw addition to fertilization with fermentation residue on emissions of greenhouse gases from soil

Im Rahmen eines Projektes zur Minderung der Frei­setzung von klimarelevanten Gasen bei Einsatz von Gärresten wurde u.a. die Wirkung einer zusätzlichen Strohdüngung in Laborversuchen geprüft. Der Stroh­zusatz erhöhte beachtlich die Kohlendioxidfreisetzung. In den Versuchen, in welchen es zu einer Ammoniak­emission kam, wurde diese durch den Strohzusatz gemindert. Die Lachgasemission wurde durch die Strohdüngung sowohl gemindert als auch erhöht. Bei einem Vergleich von Ammonium- und Nitratdüngung lag die Lachgasfreisetzung bei der Ammoniumdüngung höher als bei der Nitratdüngung. Insgesamt hatte der Stroh­zusatz aber bei beiden N-Formen eine lachgasfördernde Wirkung. Bei der Gärrestdüngung war die Lachgasemission höher als bei einer Ammoniumdüngung, wurde aber bei der Gärrestdüngung durch den Strohzusatz gemindert und bei der Ammoniumdüngung dagegen gesteigert. Der Zusatz von Stroh reduzierte sowohl die Menge an mineralischem Stickstoff im Boden als auch die aus der Düngung stammende Menge an Gesamtstickstoff. Bilanzbetrachtungen deuten darauf hin, dass es bei Strohzusatz auch zu einer erhöhten N2-Freisetzung gekommen sein kann.    As part of a project to mitigate the release of greenhouse gases due to fermentation residue fertilization the effect of an additional straw application was tested at laboratory scale. It was found that carbon dioxide release was in general markedly increased, while ammonia emission was reduced by straw application. By contrast, nitrous oxide was differently affected by the addition of straw inasmuch as either a reduction or an increase of emission rates was observed. An application of ammonium or nitrate fertilizer revealed an increase of nitrous oxide release in the presence of straw. Concerning ammonium fertilization, however, the release of nitrous oxide was higher compared to that of nitrate fertilization. In addition, the application of straw reduced both the content of mineral nitrogen in the soil as well as the amount of total soil nitrogen. Therefore, the addition of straw might even have been resulted in an increased release of dinitrogen.   &nbsp

Release of greenhouse gases from different soils under laboratory conditions

In zwei Laborversuchen wurde die Freisetzung von Ammoniak, Lachgas, Kohlendioxid und Methan aus zehn verschiedenen Böden ohne und mit Zusatz von Gärrest geprüft. Ohne Zusatz von Gärrest kam es nur zu einer Freisetzung von CO2. Mit Gärrestzusatz traten alle untersuchten Gase auf. Bei den gedüngten Böden lag eine hohe Streubreite bei den N2O-, CO2- und NH3-Freisetzungen vor. Die engste Beziehung zwischen den untersuchten Bodenparametern und den Gasfreisetzungen bestand zwischen dem Sandgehalt und der NH3-Freisetzung. Bei Gärrestzusatz erfolgte die höchste Freisetzung von CO2-Äquivalenten (Summe aller vier Gase) bei den lehmigen Sandböden. DOI: 10.5073/JfK.2014.06.02, https://doi.org/10.5073/JfK.2014.06.02In two laboratory experiments, the release of ammonia, nitrous oxide, carbon dioxide and methane from ten different soils was tested with and without the addition of fermentation residue. Without the addition of fermentation residue, there was only a release of CO2. With application of fermentation residue all investigated gases were released. In the fertilized soils, high scatter was present in the N2O, CO2 and NH3 release. The closest relationship between the studied soil parameters and the gas release existed between sand content and NH3 release. After application of fermentation residue the highest release of CO2 equivalents (sum of all four gases) was found in the loamy sand soils. DOI: 10.5073/JfK.2014.06.02, https://doi.org/10.5073/JfK.2014.06.0

Comparison of the release of nitrogen gases (NH3, N2O, N2) after application of fermentation residues

Anhand von acht Laborversuchen wird die Wirkung von Einflussfaktoren auf die Freisetzung von Stickstoffgasen nach einer Gärrestapplikation demonstriert und werden dazu Vergleiche zwischen den Gasen vorgenommen. Übereinstimmungen ergaben sich bei der NH3- und N2O-Freisetzung in Bezug auf die Temperatur und die Art der Düngung. Unterschiede zeigten sich im zeitlichen Verlauf der Gasfreisetzungen und in der Reaktion auf die Applikationsmethode, die Bodenfeuchte, die Gärrest-N-Menge und den Zusatz von Stroh sowie eines Nitrifikations­inhibitors. Die N2O- und N2-Freisetzungen nahmen mit steigender Bodenfeuchte zu. Im hohen Bodenfeuchte­bereich stieg besonders die N2O-Freisetzung an und lag über der Freisetzung von N2. Der Zusatz von Stroh zur Gärrestapplikation kann einen differenzierten Einfluss auf die N2O- und N2-Freisetzungen ausüben, der offensichtlich vom Bodenfeuchtegehalt abhängig ist. DOI: 10.5073/JfK.2015.03.02, https://doi.org/10.5073/JfK.2015.03.02On the basis of eight laboratory experiments, the effect of factors is demonstrated on the release of nitrogen gases after fermentation residue application and comparisons between gases are made. Similarities where found in the behaviour of NH3 and N2O release with respect to the influence of temperature and the applied fertilizer. Differences occurred in the temporal dynamics of gas release and in response to the application method, the soil moisture content, the rate of fertilizer N application and the addition of straw and a nitrification inhibitor. The N2O and N2 release increased with increasing soil moisture. At high soil moisture, particularly N2O release increased and was partially above the release rate of N2. The addition of straw to the application of fermentation residue showed a differential influence on N2O and N2 release, which is obviously dependent on soil moisture content. DOI: 10.5073/JfK.2015.03.02, https://doi.org/10.5073/JfK.2015.03.0

Solution Equilibria of Anticancer Ruthenium(II)-(η6-p-Cymene)-Hydroxy(thio)pyr(id)one Complexes: Impact of Sulfur vs. Oxygen Donor Systems on the Speciation and Bioactivity

Stoichiometry and stability of antitumor ruthenium(II)-eta(6)-p-cymene complexes of bidentate (0,0) hydroxypyrone and (O,S) hydroxythiopyr(id)one type ligands were determined by pH-potentiometry, H-1 NMR spectroscopy and UV-Vis spectrophotometry in aqueous solution and in dependence of chloride ion concentration. Formation of mono-ligand complexes with moderate stability was found in the case of the hydroxypyrone ligands (ethyl maltol and allomaltol) predominating at the physiological pH range. These complexes decompose to the dinuclear tri-hydroxido bridged species [(Ru-II(eta(6)-p-cymene)h(OH)(3)](+) and to the metal-free ligand at basic pH values. In addition, formation of a hydroxido [Ru-II(eta(6)-p-cymene)(L)(OH)] species was found. The hydroxythiopyr(id)one ligands (thiomaltol, thioallomaltol, 3-hydroxy-1,2-dimethyl-thiopyridone) form complexes of significantly higher stability compared with the hydroxypyrones; their complexes are biologically more active, the simultaneous bi- and monodentate coordination of the ligands in the bis complexes (ML2 and ML2H) was also demonstrated. In the case of thiomaltol, formation of tris complexes is also likely at high pH. The replacement of the chlorido by the aqua ligand in the [Ru-II(eta(6)-p-cymene)(L)(CI)] species was monitored, which is an important activation step in the course of the mode of action of the complexes, facilitating binding to biological targets

Antitumor Pentamethylcyclopentadienyl Rhodium Complexes of Maltol and Allomaltol: Synthesis, Solution Speciation and Bioactivity

The reaction of the dimer [RhIII(pentamethylcyclopentadienyl)(m-Cl)Cl]2 ([RhIII(Cp*)(m- Cl)Cl]2) with the hydroxypyrone ligands maltol and allomaltol affords complexes of the general formula [RhIII(Cp*)(L)Cl] under standard and microwave conditions. The organometallic compounds were characterized by standard analytical methods and in the case of the allomaltol derivative in the solid state by single-crystal X-ray diffraction analysis. The complexes showed similar cytotoxicity profiles and were proved to be moderately active against various human cancer cell lines. The stoichiometry and stability of these complexes were determined in aqueous solution by pH-potentiometry, 1H NMR spectroscopy and UVvisible spectrophotometry. Speciation was studied in the presence and in the absence of chloride ions. Hydrolysis of [RhIII(Cp*)(H2O)3]2+ gave dimeric mixed hydroxido species [(RhIII(Cp*))2(m-OH)3]+ and [(RhIII(Cp*))2(m-OH)2Z2] (Z = H2O/Cl‒). Formation of the mononuclear complexes [RhIII(Cp*)(L)Z] of maltol and allomaltol with similar and moderate stability was found. These species predominate at physiological pH and decompose only partially at micromolar concentrations. In addition, hydrolysis of the aqua complex or the chlorido/hydroxido co-ligand exchange resulted in the formation of the mixed-hydroxido species [RhIII(Cp*)(L)(OH)] in the basic pH range. Replacement of the chlorido by an aqua ligand in the complex [RhIII(Cp*)(L)Cl] was monitored and with the help of the equilibrium constants the extent of aquation at various chloride concentrations of the extra- and intracellular milieu can be predicted. Complexation of these RhIII complexes was compared to analogous [RuII(h6-p-cymene)] species and higher conditional stabilities were found in the case of the RhIII compounds at pH 7.4