@misc{VesteLittmannKunnekeetal., author = {Veste, Maik and Littmann, Thomas and Kunneke, Anton and Du Toit, Ben and Seifert, Thomas}, title = {Windbreaks as part of climate-smart landscapes reduce evapotranspiration in vineyards, Western Cape Province, South Africa}, series = {Plant, Soil and Environment}, volume = {66}, journal = {Plant, Soil and Environment}, number = {3}, issn = {1214-1178}, doi = {10.17221/616/2019-PSE}, pages = {119 -- 127}, abstract = {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 (Carri{\`e}re) 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.}, language = {en} } @misc{AdesipoAkinbiolaAwotoyeetal., author = {Adesipo, Adegbite Adeleke and Akinbiola, Sehinde and Awotoye, Olusegun O. and Salami, Ayobami T. and Freese, Dirk}, title = {Impact of mining on the floristic association of gold mined sites in Southwest Nigeria}, series = {BMC Ecology}, volume = {20}, journal = {BMC Ecology}, issn = {1472-6785}, doi = {10.1186/s12898-020-00276-9}, pages = {13}, abstract = {Background: Occurrences in land use, human activities and climate change have both direct and indirect influences on the environment. Of interest for this study is mining; a common activity in developing countries such as Nigeria which is endowed with over 34 solid minerals. The gold mining sites in the Southwest region of the country is predominantly by Artisanal and Small-Scale Mining (ASM). Though the benefits are known, its induced consequences are enormous. To understand its extent of floristic diversity, identification of functional plants and plant species surviving on the mined sites (despite its characterized mining and alteration level); this study compared the floristic composition of an abandoned mining site (Site 1), an active mining site (Site 2) and an undisturbed vegetation sites (Control) of similar vegetation zone. Results: A total of 54, 28 and 37 species belonging to 31, 20 and 23 families were found on Site 1, Site 2 and the control site, respectively. It shows that the floristic composition of all the sites has been altered due to its past intense agricultural colonization and human activities, but severe on Site 1 and 2 due to mining. Lots of the identified species are functional species and stand as ecological indicators. Species such as Acanthus montanus and Icacina richantha found on the Control sites are native and significance but species such as Capsicum frutescens and Crassocephalum crepidioides on Site 2 are due to human inference while most species on Site 1 shows both original and altered floristic composition (e.g. Adenia venenata and Grewia flavescens). Conclusions: Apart from the on-going farming activities, ASM activities such as pollution, deforestation and exposure of the forest soils to direct sunlight has greatly stressed and disturbed the floristic composition, species richness, life form patterns, of the mined sites as well as introduction of non-native plant species. It is therefore necessary to develop effective approaches and policies to curb these illegal ASM activities, empower the community (especially youths), stabilize the economy and establish sustainable development strategies with adequate reclamation measures.}, language = {en} } @misc{AhmedGypserFreeseetal., author = {Ahmed, Ashour A. and Gypser, Stella and Freese, Dirk and Leinweber, Peter and K{\"u}hn, Oliver}, title = {Molecular level picture of the interplay between pH and phosphate binding at the goethite-water interface}, series = {Physical Chemistry Chemical Physics}, volume = {22}, journal = {Physical Chemistry Chemical Physics}, number = {45}, issn = {1463-9084}, doi = {10.1039/d0cp04698a}, pages = {26509 -- 26524}, abstract = {The soil pH plays a substantial role in controlling phosphorus (P) adsorption and mobilization. These processes are strongly affected by the phosphate interaction strength with P-fixing soil minerals such as goethite. The target of the current contribution is to draw a molecular level picture of the interplay between pH and phosphate binding at the goethite-water interface via a joint experimental-theoretical approach. Periodic density functional theory (DFT) calculations were carried out to provide a molecular level understanding of the pH dependence of P adsorption. To validate the modeling approach, adsorption experiments of phosphate at goethite were performed in the pH range of 4-12. There was agreement between experiments and simulations in the description of the adsorption behavior by two pH-dependent successive stages. The adsorption increases along the pH change from 4 to 8. A further increase of pH leads to a decrease of adsorption. By comparing with literature data it is concluded that the first stage will be observed only if there is no significant change of the surface charge at low pH. Moreover, the molecular modeling results point to the abundance of the monodentate (M) binding motif at both extremely low and high pH ranges. Otherwise, the bidentate (B) one is predominant along the intermediate pH range. These observations could resolve the existing debate about the assignment of phosphate-goethite binding motifs. Furthermore, the results point to a decrease of pH upon phosphate sorption due to an induced acidification of soil solution. The present joint experimental-theoretical approach provides a better understanding and description of the existing phosphate sorption experiments and highlights new findings at the atomistic/molecular scale.}, language = {en} } @misc{KanzlerBoehmFreese, author = {Kanzler, Michael and B{\"o}hm, Christian and Freese, Dirk}, title = {The development of soil organic carbon under young black locust (Robinia pseudoacacia L.) trees at a post-mining landscape in eastern Germany}, series = {New Forests}, volume = {52 (2021)}, journal = {New Forests}, number = {1}, issn = {1573-5095}, doi = {10.1007/s11056-020-09779-1}, pages = {68}, abstract = {The aim of this study was to evaluate the potential of short rotation alley cropping systems (SRACS) to improve the soil fertility of marginal post-mining sites in Brandenburg, Germany. Therefore, we annually investigated the crop alleys (AC) and black locust hedgerows (ABL) of a SRACS field trail under initial soil conditions to identify the short-term effects of tree planting on the storage of soil organic carbon (SOC) and its degree of stabilization by density fractionation. We detected a significant increase in SOC and hot-water-extractable organic C (HWEOC) at ABL, which was mainly restricted to the uppermost soil layer (0-10 cm). After 6 years, the SOC and HWEOC accumulation rates at ABL were 0.6 Mg and 46 kg ha-1 year-1, which were higher than those in the AC. In addition, comparatively high stocks of approximately 4.6 Mg OC and 182 kg HWEOC ha-1 were stored in the ABL litter layer. Density fractionation of the 0-3 cm soil layer at ABL revealed that the majority of the total SOC (47\%) was stored in the free particulate organic matter fraction, which was more than twice that of the AC. At the same time, a higher and steadily increasing amount of SOC was stored in the occluded particulate organic matter fraction at ABL, which indicated a high efficiency for SOC stabilization. Overall, our findings support the suitability of black locust trees for increasing the soil fertility of the reclaimed mining substrate and, consequently, the high potential for SRACS to serve as an effective recultivation measure at marginal sites.}, language = {en} } @misc{NsiahSchaaf, author = {Nsiah, Paul Kofi and Schaaf, Wolfgang}, title = {Subsoil Amendment With Poultry Manure as Topsoil Substitute for Promoting Successful Reclamation of Degraded Mine Sites in Ghana}, series = {Journal of Natural Resources and Development}, volume = {10}, journal = {Journal of Natural Resources and Development}, issn = {0719-2452}, pages = {1 -- 12}, abstract = {Background: Despite the key role topsoil plays in reclamation, there are situations where topsoil is in deficit or unavailable, especially at degraded and abandoned mine sites in Ghana. The sites pose serious ecological and safety risks, underscoring the urgent need to finding alternative substrate for restoration. This study investigated the feasibility of using amended-subsoil as topsoil substitute for reclamation. The hypothesis was that amendment of stockpiled-subsoil with poultry manure positively influences tree growth and ground vegetation cover (GVC), which promote better soil stabilization at degraded mine sites. A graded waste-rock dump was covered with a 70 cm layer of the stockpiled subsoil at Newmont Ghana Gold Limited. Two experimental plots (24 × 15 m) were established with the treatments poultry manure (PLM 23 t ha-1) and control (no PLM), followed by seeding of Cowpea (Vigna unguiculata) and planting of potted-seedlings of five forest tree species. The Laser-point-quadrat method was used to estimate GVC, whereas erosion was visually observed. Diameter and height data of planted trees and surviving numbers were collected. Results: There was significant increase in tree growth and in GVC for the poultry manure treatment compared to the control. The manure provided sufficient nitrogen to overcome nitrogen deficiency and facilitated quicker and stronger vegetation growth that yielded superior soil stabilization. Conclusions: The findings demonstrate the potential of manure application in promoting successful restoration of the many degraded and abandoned mine sites in Ghana to productive uses.}, language = {en} } @misc{OpreiSchreckingerKholiavkoetal., author = {Oprei, Anna and Schreckinger, Jos{\´e} and Kholiavko, Tatiana and Frossard, Aline and Mutz, Michael}, title = {Functional and structural recovery of stream biofilms at the habitat scale is based on the individual disturbance history}, series = {Ergebnisse der Jahrestagung 2019 in M{\"u}nster}, journal = {Ergebnisse der Jahrestagung 2019 in M{\"u}nster}, publisher = {Eigenverlag der DGL}, address = {Essen}, isbn = {978-3-9818302-4-8}, pages = {216}, language = {en} } @misc{GypserFreese, author = {Gypser, Stella and Freese, Dirk}, title = {Mobilization of P from crystalline and amorphous Fe- and Al-hydroxides}, series = {EGU General Assembly 2020}, journal = {EGU General Assembly 2020}, doi = {10.5194/egusphere-egu2020-2871}, language = {en} } @misc{GerwinSchaaf, author = {Gerwin, Werner and Schaaf, Wolfgang}, title = {Abiotic and biotic drivers of ecosystem development - results from Chicken Creek Catchment}, series = {EGU General Assembly 2020, Online, 4-8 May 2020}, journal = {EGU General Assembly 2020, Online, 4-8 May 2020}, doi = {10.5194/egusphere-egu2020-7216}, language = {en} } @misc{Schaaf, author = {Schaaf, Wolfgang}, title = {The role of geodiversity in ecosystem development}, series = {EGU General Assembly 2020, Online, 4-8 May 2020}, journal = {EGU General Assembly 2020, Online, 4-8 May 2020}, doi = {10.5194/egusphere-egu2020-1415}, language = {en} } @misc{SheppardBohnReckziegelBorrassetal., author = {Sheppard, Jonathan P. and Bohn Reckziegel, Rafael and Borrass, Lars and Chirwa, Paxie W. and Cuaranhua, Claudio J. and Hassler, Sibylle K and Hoffmeister, Svenja and Kestel, Florian and Maier, Rebekka and M{\"a}licke, Mirko and Morhart, Christopher and Ndlovu, Nicholas P. and Veste, Maik and Funk, Roger and Lang, Friedericke and Seifert, Thomas and du Toit, Ben and Kahle, Hans-Peter}, title = {Agroforestry: An Appropriate and Sustainable Response to a Changing Climate in Southern Africa?}, series = {Sustainability}, volume = {12}, journal = {Sustainability}, number = {17}, doi = {10.3390/su12176796}, abstract = {Agroforestry is often discussed as a strategy that can be used both for the adaptation to and the mitigation of climate change effects. The climate of southern Africa is predicted to be severely affected by such changes. With agriculture noted as the continent's largest economic sector, issues such as food security and land degradation are in the forefront. In the light of such concerns we review the current literature to investigate if agroforestry systems (AFS) are a suitable response to the challenges besetting traditional agricultural caused by a changing climate. The benefits bestowed by AFS are multiple, offering ecosystem services, influence over crop production and positive impacts on rural livelihoods through provisioning and income generation. Nevertheless, knowledge gaps remain. We identify outstanding questions requiring further investigation such as the interplay between trees and crops and their combination, with a discussion of potential benefits. Furthermore, we identify deficiencies in the institutional and policy frameworks that underlie the adoption and stimulus of AFS in the southern African region. We uphold the concept that AFS remains an appropriate and sustainable response for an increased resilience against a changing climate in southern Africa for the benefit of livelihoods and multiple environmental values}, language = {en} }