TY - GEN A1 - Veste, Maik A1 - Littmann, Thomas A1 - Kunneke, Anton A1 - Du Toit, Ben A1 - Seifert, Thomas T1 - Windbreaks as part of climate-smart landscapes reduce evapotranspiration in vineyards, Western Cape Province, South Africa T2 - Plant, Soil and Environment N2 - Under the conditions of climate change in South Africa, ecological and technical measures are needed to reduce the water consumption of irrigated crops. Windbreak hedges are long-rated systems in agriculture that significantly reduce wind speed. Their possibilities to reduce evapotranspiration and water demand are being investigated at a vineyard in the Western Cape Province, South Africa. Detailed measurements of meteorological parameters relevant for the computation of reference and crop-specific evapotranspiration following the FAO 56 approaches within a vineyard in the Western Cape Province of South Africa have shown the beneficial effect of an existing hedgerow consisting of 6 m high poplars (Populus simonii (Carrière) Wesm.). With reference to a control station in the open field, the mean wind speed in a position about 18 m from the hedgerow at canopy level (2 m) was reduced by 27.6% over the entire year and by 39.2% over the summer growing season. This effect leads to a parallel reduction of reference evapotranspiration of 15.5% during the whole year and of 18.4% over the growing season. When applying empirical crop-specific Kc values for well-irrigated grapes, the reduction of evapotranspiration is 18.8% over the summer growth period. The introduced tree shelterbelts are a suitable eco-engineering approach to reduce water consumption and to enhance water saving in vineyards. KW - dry areas KW - viticulture KW - climate change KW - agroforestry Y1 - 2020 UR - https://www.agriculturejournals.cz/web/pse.htm?type=article&id=616_2019-PSE U6 - https://doi.org/10.17221/616/2019-PSE SN - 1214-1178 SN - 1805-9368 VL - 66 IS - 3 SP - 119 EP - 127 ER - TY - GEN A1 - Fischer, Thomas A1 - Kholiavko, Tatiana A1 - Schaaf, Wolfgang A1 - Veste, Maik T1 - Soil respiration responses of moss and lichen biocoenoses to moderate and severe rain events after summer drought in a temperate early-successional ecosystem T2 - Ecohydrology N2 - It is commonly accepted that CO2 efflux increases with soil water content in aerated soils and that rewetting after periods of soil drying can result in respiration pulses. It has further been shown that soil pores may become water logged which can impede soil gas exchange. The present study aimed to quantify the carbon response of moss (Polytrichum piliferum) and lichen (Cladonia coniocraea) biocoenoses to different quantities of rain in an artificial catchment, which granted that the starting point of the development of both biocoenoses was the same. To address this aim, we conducted in situ soil moisture and soil respiration measurements, where soil respiration was hypothesised to emerge from a cryptogamic vegetation layer and from mineral soil beneath. We found that higher water-holding capacity of the moss layer and higher accumulation of organic matter in the upper mineral soil under mosses result in higher amounts of water stored near the surface. As a consequence, evaporation of water as well as pulses of CO2 efflux after moderate rain following a period of drought were higher in the moss biocoenosis, where the upper mineral soil was of key importance. In contrast, the lichen biocoenosis facilitated penetration of rainwater into the deep soil. Superimposing rewetting pulses, near-saturation of soil pores with water after severe rain resulted in gas exchange inhibition and diminished soil respiration until subsequent aeration in both biocoenoses KW - biocrusts KW - Hühnerwasser KW - respiration KW - soils Y1 - 2023 U6 - https://doi.org/10.1002/eco.2578 SN - 1936-0592 VL - 16 IS - 7 ER - TY - GEN A1 - Geldenhuys, Heinrich A1 - Lötze, Elmi A1 - Veste, Maik T1 - Fruit Quality and Yield of Mandarin (Citrus reticulata) in Orchards with Different Windbreaks in the Western Cape, South Africa T2 - Erwerbs-Obstbau N2 - Windbreaks, trees, structures, and shade nets are used in South Africa to protect citrus orchards from wind scar damage to avoid major losses in export quality. Severe southeasterly winds in the Western Cape during spring and summer are the main causes of significant external peel damage. In this study, wind scar damage of ‘Tango’ mandarin (Citrus reticulata) fruit was quantified at different distances from established Casuarina cunninghamiana (Beefwood) and Populus simonii (Chinese Poplar) windbreaks around Stellenbosch, Western Cape, South Africa. The yield efficiency was not significantly affected by distance from the windbreak in either of the trials. Fruit at 2 H and 3 H had significantly lower ratios of total soluble solids to titratable acidity, but export standards for mandarins were still met. The wind speed was consistently higher at 16 H, compared with 3 H during summer. The highest packout (class 1 fruit) was observed near the windbreak (3 H) and decreased as the distance increased towards 10 H and 16 H. There were no significant differences for severe wind scar damage incidence between the distance treatments. Our results confirmed the impact of wind on external fruit quality and the limitation of tree-based windbreaks with an increase in distance, which partly supports the current movement towards full enclosure of orchards with shade nets. KW - Agroforestry KW - Citrus orchards KW - yield KW - South Africa Y1 - 2022 U6 - https://doi.org/10.1007/s10341-022-00725-3 SN - 1439-0302 VL - 65 (2023) IS - 4 SP - 959 EP - 969 ER - TY - GEN A1 - Veste, Maik A1 - Halke, Christian A1 - Garbe, Daniel A1 - Freese, Dirk T1 - Einfluss von Stickstoffdüngung und Kompost auf Photosynthese und Wachstum der Virginiamalve (Sida hermaphrodita Rusby) T2 - Journal für Kulturpflanzen N2 - Als mehrjährige Bioenergiepflanze kann Sida hermaphrodita eine wichtige Rolle für den Anbau auf marginalen Standorten in der nahen Zukunft spielen. In einem kontrollierten Topfexperiment wurde der Einfluss von verschiedenen Kompostgehalten (10, 20, 30, 50%) und mineralischem Stickstoffdünger (100 kg N ha–1) auf Biomasse, Wuchshöhe und Kohlenstoffallokation während der Etablierungsphase untersucht. Weiterhin wurden ökophysiologische Parameter (Gaswechsel, Chlorophyllfluoreszenz, Chlorophyllgehalte) mit nicht-destruktiven Methoden bestimmt. Die Ergebnisse des Experimentes zeigen, dass sowohl die Stickstoffdüngung als auch die Kompostgabe positive Effekte für das Wachstumsverhalten hat. Während der Etablierungsphase erreichten die gedüngten Pflanzen eine mittlere Pflanzenhöhe von bis zu 127 cm (maximale Wuchshöhe 168 cm). Die Photosynthese wurde nicht durch die unterschiedlichen Behandlungen beeinflusst. Die mittlere CO2-Austauschrate variiert zwischen 5,8 und 9,9 μmol m–2 s–1 und die Elektronentransportrate zwischen 34,5 und 53,9 μmol m–2 s–1. Die Verwendung von Kompost und Stickstoff ist für eine bessere Biomasseproduktion von Sida in marginalen Böden möglich, auch wenn das Wachstum im ersten Jahr limitiert ist und es negative Rückwirkungen auf die Bestandesetablierung gibt. Y1 - 2016 U6 - https://doi.org/10.1399/JFK.2016.12.13 SN - 1867-0911 SN - 1867-0938 VL - 68 IS - 12 SP - 423 EP - 428 ER - TY - GEN A1 - Kidron, Giora J. A1 - Veste, Maik A1 - Lichner, Lubomir T1 - Biological factors impacting hydrological processes: Pecularities of plants and biological soil crusts T2 - Journal of Hydrology and Hydromechanics N2 - The effects of biological factors on the water cycle and subsequently on hydrological processes have wide and profound consequences on ecosystem structure, function and management. A profound understanding of their effects is of prime importance especially in light of climate change projection KW - Biological soil crusts Y1 - 2021 U6 - https://doi.org/10.2478/johh-2021-0031 SN - 1338-4333 VL - 69 IS - 4 SP - 357 EP - 359 ER - TY - GEN A1 - Küppers, Manfred A1 - Küppers, Barbara I. L. A1 - Horna, Viviana A1 - Veste, Maik A1 - Zimmermann, Reiner A1 - Lauerer, Marianne A1 - Aas, Gregor T1 - Green barks of trees from drought deciduous forests ("bosque seco") in northern Peru/southern Ecuador do not perform CAM T2 - Basic and Applied Dryland research N2 - Trees from drought deciduous forests (“bosque seco”) in northern Peru and southern Ecuador regularly shed their leaves at the onset of seven months-long periods without rain. This way they very effectively reduce the bulk water consumption by leaf transpiration, still loosing small amounts of water through their bark, but at the risk of too little or no carbon gain when leaf-less. Seven species studied here have good developed green cortex tissue on stems and axes, as especially evident for the “bottle tree” Ceiba trischistandra (A. Gray) Bakhuisen (Bombacaceae). In several leaf-less tree species at the end of summer drought, when xylem sap flows are very low, indications of higher xylem flows at night as compared to day-time were found, which led to the question of whether the trees are capable of performing CAM in their axes. However, although quite low in some cases, the pH of the cortex tissues did not fluctuate diurnally. In addition, no night-time carbon uptake could be observed. Although no net carbon gain was measured in C. trischistandra and Erythrina smithiana Krukoff (Fabaceae) photosynthetic activity of the green cortex was sufficient to re-assimilate between 50% to 60% of the carbon released by mitochondrial respiration. In contrast, the obligate CAM plant Cereus diffusus (Britton & Rose) Werdermann (Cactaceae), which was studied as a reference in the same environment, showed both diurnal pH-fluctuations in its green tissue with lowest values before sun rise, and net carbon fixation at night. Y1 - 2015 UR - https://www.researchgate.net/publication/280945188 U6 - https://doi.org/10.1127/badr/2015/0002 SN - 1864-3191 ER - TY - GEN A1 - Veste, Maik T1 - Biologische Bodenkrusten - Pioniere der Böden T2 - Naturmagazin Berlin - Brandenburg N2 - Nach extremen Störungen durch Brände, Vulkanausbrüchen und Hangrutschungen, aber auch menschlichen Eingriffen werden Böden mehr oder weniger zerstört und vegetationsarm. Es entstehen sogenannte initiale Rohböden, die durch Veränderung der Bodenstruktur, Minderung der Wasserhaltekapazität als auch durch Nährstoffarmut extrem beeinflusst werden. Dabei haben anfängliche und nährstoffarme Ökosysteme, wie Grasländer und Offenlandschaften, aus Sicht des Naturschutzes einen hohen Wert für die Landschaft und sind in der intensiv genutzten Kulturlandschaft Mitteleuropas selten geworden. Insbesondere bieten Binnendünen, wie sie in Norddeutschland häufig sind, Potenzial für die Entwicklung von initialen Lebensräumen mit ihren spezifisch angepassten Pflanzen. Neben den Pionierarten werden die Rohböden, wie sie nach Störungen entstehen, zuerst durch verschiedene blütenlose Pflanzen, den sogenannten Kryptogamen, besiedelt. KW - Störungen KW - Biologische Bodenkrusten KW - Sanddünen KW - Brandenburg Y1 - 2022 SN - 0935-7602 VL - 36 IS - 1 SP - 14 EP - 15 ER - TY - GEN A1 - Lebzien, Stefan A1 - Veste, Maik A1 - Fechner, H. A1 - Koning, Laurie Anne A1 - Mantovani, Dario A1 - Freese, Dirk T1 - The Giant Knotweed (Fallopia sachalinensis var. Igniscum) as a new plant resource for biomass production for bioenergy T2 - EGU General Assembly 2012, held 22-27 April, 2012 in Vienna, Austria Y1 - 2012 N1 - EGU2012-6060 PB - European Geophysical Society CY - Kattenburg-Lindau ER - TY - GEN A1 - Ma, Yunyao A1 - Weber, Bettina A1 - Raggio Quílez, José A1 - Colesie, Claudia A1 - Veste, Maik A1 - Bader, Maaike Y. A1 - Porada, Philipp T1 - Determining key drivers of the annual carbon budget of biocrusts in different climatic zones T2 - EGU General Assembly 2022, Vienna, Austria & Online | 23–27 May 2022 N2 - Biocrusts are distributed over all climate zones of the world and they substantially contribute to ecosystem functioning. Their growth, determined by their carbon balance, can be affected by various climatic drivers. The effects of individual drivers are clear from laboratory experiments, but the relative importance of different drivers along climatic gradients and their underlying mechanisms are largely unknown. Moreover, the effects of seasonal acclimation on the annual carbon balance are not fully understood either. Therefore, we aim at determining the level and variation of annual biocrust carbon balances and their connection to climatic drivers along environmental gradients. In addition, we explore the role that acclimation plays in the carbon balance of biocrusts KW - biocrusts, photosynthesis, carbon Y1 - 2022 UR - https://meetingorganizer.copernicus.org/EGU22/EGU22-3714.html U6 - https://doi.org/10.5194/egusphere-egu22-3714 ER - TY - GEN A1 - Veste, Maik A1 - Grey, Kerry-Anne A1 - Gottschalk, Nadine A1 - Trachte, Katja A1 - Midgley, Guy F. T1 - Can shelterbelt trees reduce evapotranspiration and ecophysiological stress in irrigated vineyards and citrus orchards? A transcontinental experiment in the Western Cape, South Africa and Lower Lusatia, Germany T2 - Landscape 2021 - Diversity for Sustainable and Resilient Agriculture N2 - In the context of ongoing climate change and increasing population, there is an urgent need to optimize the water consumption of surface and groundwater in agricultural production. In recent years, intensive irrigated viticulture and horticulture have faced increasing demand pressure in many water-limited areas including the Western Cape Province in South Africa. Shelterbelts of trees are often used to reduce wind speed and water demands as an eco-engineering measure directly influencing soil evaporation and crop transpiration. Objectives are (i) to evaluate the extent of impacts of wind speed from shelterbelts at canopy level in citrus orchards and vineyards (ii) to assess the wind effects at leaf level including leaf temperature and related ecophysiological performance in irrigated vineyards. Y1 - 2021 U6 - https://doi.org/10.13140/RG.2.2.34333.03043 ER -