Effects of Land Use and Management on Soil Hydraulic Properties

Abstract Soil hydraulic properties are among the most importantparameters that determine soil quality and its capabilityto serve the ecosystem. Land use can significantlyinfluence soil properties, including its hydraulic conditions;however, additional factors, such as changes in climate(temperature and precipitation), can further influencethe land use effects on soil hydraulic properties. Inorder to develop possible adaptation measures and mitigateany negative effects of land use and climatic changes,it is important to study the impact of land use and changesin land use on soil hydraulic properties. In this paper,we summarize recent studies examining the effect of landuse/land cover and the associated changes in soil hydraulicproperties, mainly focusing on agricultural scenariosof cultivated croplands and different tillage systems.</jats:p

Myth or reality? A disquisition concerning the photostability of bismuth-based photocatalysts

Photocatalysis is a well-known and extensively investigated field within advanced oxidation processes. Numerous papers have been reported that the semiconductors applied were photostable and potentially reusable based on the degradation efficiencies observed. However, researchers did not attach enough importance to investigate the residual catalysts in most cases. Here, we report on some important alterations that occurred during photocatalytic experiments, such as acid-induced and light-assisted structure break-down and complete transformation of catalysts, which could place their photostability into a new perspective. In this work, the photostability of five, increasingly popular bismuth-based oxides (Bi2WO6, BiVO4, BiOI, BiOCl, and BiOBr) were investigated in the presence of various carboxylic acids (oxalic acid, formic acid, salicylic acid, malonic acid, and ascorbic acid), focusing on the crystallographic and morphological alterations of the residual photocatalysts. When investigating the resistance of the photocatalysts to oxalic acid, the formation of bismuth oxalate hy- droxide was observed in all cases. At the same time, most components of the catalysts appeared in the liquid phase in high amounts. Similar transformations occurred to a lesser extent for the other acids, which was deduced to be related to the acidic strength and proton concentration. We also highlighted that in some instances, during photocatalytic processes, the occurrence of light-assisted acid-induced reactions must be considered as well

Eső hatása a Csorsza-patak vízgyűjtőjének téli hidrológiai folyamataira

A vizsgálat 42 órája alatt (2016. február 3–4.) és az előtte lévő öt hónapban összesen négy nagyobb mennyiségű csapadékesemény történt a Csorsza-patak vízgyűjtő területén. A vizsgált esőzés időszakában 21,6 mm csapadékmennyiség hullott összesen a vízgyűjtő területére 5 órás intervallumban. A csapadékesemény első órájában a patak zavarosság értéke majdnem megduplázódott, viszont így is viszonylag alacsony szinten maradt a későbbiekben mért értékekhez viszonyítva. Az esőzés kezdetét követő 7. órában emelkedett meg jelentősen a zavarosság mértéke, több mint 14-szeresére, a 13–14. órában pedig 34-szeresére nőtt a vizsgálat előtti naphoz viszonyítva. A Csorsza-patak zavarosságának nagysága nem sokkal a tetőzést követően nagy mértékben lecsökkent, 13 órával később pedig hasonló értékeket mutatott, mint a vizsgálat előtti esőzés nélküli időszakban. A nagyobb esőzések alkalmával az alacsonyabb területeken fekvő, minimális lejtésű szántó esetében telítettséghez közeli talajnedvesség-tartalom volt megfigyelhető, míg a legkisebb talajnedvesség-tartalom ingadozás az esőzést követően a gyepes és az erdős területekre volt jellemző. A jelen vizsgálatban összegyűjtött adatok alapján a Csorsza-patakból a Balatonba bekerülő talajhordalék mennyisége a téli időszakban, az erozív esőzések gyakoriságának ismeretében könnyebben és pontosabban becsülhető. Annak érdekében, hogy az éves átlag lebegtetett hordalék mennyiségének a becslését pontosabban el tudjuk végezni, több időszakos mérésre volna szükség. Munkánkat az OTKA K—101065 projekt, az OTKA PD—116157 és OTKA PD—116084 kutatási projekt, valamint a Bolyai János Kutatási Ösztöndíj támogatta. Külön köszönet Mózes Mariann és Bányász Ágnes részére a laboratóriumi vizsgálatokban nyújtott segítségükért, valamint Szegvári Győző és kollégáinak a zánkai vízminták gyűjtésében való hatalmas segítségükért. | The amount of suspended sediments leaving the Csorsza catchment area over time was investigated on the basis of turbidity measurements. These were taken at a distance of approximately 3.4 km from the vegetative study sites daily until the start of the erosive rain event, and every one or two hours during and after the event for a total of 42 hours. Soil water contents and soil temperatures were continuously measured at three depths (15, 40 and 70 cm below the surface), while overall weather data were obtained either from local measurements at the sites (for precipitation) or from meteorological stations close to the pilot area (for other meteorological variables). During an erosive rainfall event (precipitation = 21.6 mm; 3 Feb. 2016), a rain gauge was placed at the study site to measure precipitation intensities. During the 3-hour heavy rain event, precipitation rates of 5, 6 and 6 mm/h were recorded. Water turbidity measurements showed a good correlation with the amount of precipitation. During the erosive precipitation event, water turbidity increased considerably to approximately 6 times the background value (from 30–70 FNU to 300 FNU, where FNU stand for Formazin Nephelometric Unit) within two hours of the rain event. The greatest turbidity (~900 FNU) was measured 6 hours after the initial spike; but 5 hours after the peak the measured turbidity values were already similar to values prior to the precipitation event

Chapter 19 - Soil CO2 Emissions in a Long-Term Tillage Treatment Experiment A2 - Muñoz, María Ángeles

Abstract The aim of our study was to investigate the effect of plowing (P) and no-tillage (NT) management on soil CO2 emissions from an arable field (i.e., winter wheat) in a 13- year-old experiment. In 2015, CO2 measurements were taken weekly in P and NT during the growing season and biweekly during the dormant season using the static chamber technique. Measurements were more frequent in a 7-day campaign scheduled right before and immediately after a soil disturbance caused by plowing to detect the short-term effects of soil management on CO2 emissions. We investigated the relationship among soil CO2 emissions, soil temperature, and soil water content. Soil CO2 emissions increased during the vegetation period and were higher in NT than P, although they were only significant from jointing to maturity stages. In contrast, CO2 emissions were higher in P compared to NT at a relatively short but well-monitored measurement interval just after plowing. Long-term systematic plowing resulted in lower CO2 emissions than that in NT during vegetation season, but a sudden pulse in CO2 emissions were detected in P directly after soil disturbance caused by plowing. These observations indicate that plowing can temporarily have a major effect on soil CO2 emissions