TY - THES A1 - Meyer zu Drewer, Johannes T1 - Soil- and Tree- Biomass Carbon as Future Farming Commodity for Smallholders in Tropics and Sub- Tropics - A Concept Review N2 - Facing prevalent soil degradation, population growth and climate change it is vital to wildly deploy versatile carbon farming practices [CF] to increase soil organic carbon [SOC] stocks and consecutive restore soils, increase their productivity and climate resilience while directly mitigating climate change through sequestration of greenhouse gas- [GHG] derivatives, such as CO₂-Carbon, in agricultural landscapes. The global aggregated mitigation potential of up to 11 GtCO₂eq yrˉ¹ (medium confidence) resulting from afforestation, SOC increment and biochar application in the land use sector can only be realised when including smallholder farmers which are in stewardship of 60% of the global arable lands. Currently soil carbon sequestration receives extensive attention, but efficient schemes to financially support smallholder transition towards carbon farming practices are lacking. Linking these smallholder structures to the global carbon markets by verifying and trading carbon offsets generated through climate smart farming practices is a new attempt to generate the required funding for transition – turning carbon into a new farming commodity for smallholders. This paper reviews approaches to SOC monitoring required for quantification and verification of offsets, based on the evaluation of methods used in the Nepalese smallholder carbon project: Forest Gardens for Closing the Global Carbon Cycle [FCGC]. Further it compares the project innovations of the FCGC with other distinguished case studies of current projects implementing carbon as a farming commodity in a tropical- subtropical smallholder context. A strong variability in SOC pattern as identified in the FCGC project, is inherent to smallholder systems, the cost of representative, direct measurements of such heterogeneous SOC distributions may be cost prohibitive. For smallholder carbon projects of aggregated scale, process-based models to determine SOC fluxes should be employed or the agricultural intervention be focused on tree- biomass- carbon which is quantifiable in a less resource demanding manners. Among the identified project innovations are: Real- time in-situ GIS applications, an innovative approach for monitoring fragmented areas under intervention; The household segment of the voluntary carbon market as a new target group to be explored; Biochar as a multifunctional soil amendment for long-term carbon sequestration; Participatory schemes for monitoring and extension services to build capacity and foster participation; and mobile money approaches to lower transaction costs and likelihood of corruption. The direct financial return from carbon- credits to the farmer is minor, thus it is imperative for the project design to utilize agricultural interventions fostering co-benefits, which are tangible to the farmer in the short to medium term and will serve as the main incentive for the adoption of CF techniques. KW - Carbon farming KW - Carbon sequestration KW - Smallholder agriculture KW - Carbon finance KW - Climate change mitigation Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-3646 ER - TY - THES A1 - Tanzin, Tamanna T1 - Assessment of growth and yield potential of different vegetable amaranth type in Kleve, Germany N2 - Amaranthus belongs to the Amaranthaceae family which has approximately 70 species. It is considered as an underutilized plant but some research in the recent years showed that it is a promising plant for future nutrition supply. Amaranths are widely known for its nutritional value and their easy growing habit. This underutilized plant can become a good option for the commercial growers because it is easy to grow, it has high nutritional value and low maintenance cost. Many species of the Amaranthus genus are known as annual weeds, some are used as a vegetable and ornamental plants, some are known as pseudocereals which are mainly used for their grain. The core objective of this study was to assess the growth and yield potential of different vegetable amaranths to select a suitable variety for Kleve, Germany. Eight vegetable amaranths variety (Leafy variety and Stem variety) were grown in the experimental garden of Hochschule Rhein-Waal University. A seed germination test was also conducted at thelife science lab to observe the best seed germination rate at different temperatures. Plant height, number of leaves per plant were measured continuously after two weeks of sowing till the harvest week. The fresh and dry weight of leaf, stem and root were measured after final harvest. The statistical analysis of growth and yield performance of stem and leafy varieties were done separately. Leafy varieties showed a high variation in yield and germination rate than stem varieties. Leafy variety 'Surinamese Spinach'(L7) and 'Marog Green' (L8) excelled in all yield parameters whereas 'Chinese Spinach' (L6) was consistent in low growth and yield. Stem variety 'Danta Bhutan' (S2) and 'Danta Lusina' (S3) showed low yield performance. All the varieties showed a high germination rate above 20°C in seed germination test. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-2711 ER - TY - THES A1 - Richter, Sebastiaan T1 - The influence of lime, iron sulphate-lime mixtures, and iron compounds on bioavailable phosphorous N2 - Available nutrients for higher plants in the soil are crucial in agriculture and can be repressed by farming practices. The objective of this thesis was to determine if the application of a lime-FeSO4 mixture reduces the available phosphorus for higher plants further than conventional liming. For this, soils from the Lower Rhine region in Germany with different soil properties were collected, treated with different applications, and incubated over a predefined time. Aerobic and anaerobic conditions were created by raising the soils’ water content to 50% and 100% of their maximum water holding capacity. Bioavailable phosphorus was extracted from the incubated samples with the Calcium-acetate-lactate (CAL) method, and analysed in the Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Statistical analysis was conducted with the open-source program “R for statistical computing”. Results showed that not the treatment but rather the type of soil had a significant effect on the phosphorus availability. At some extent the WHC significantly influenced the phosphorus availability. In general, lime-FeSO4 mixtures showed a tendency to have higher phosphorus availability than conventional liming. Effects of long-term field application cannot be determined because the experiment was conducted under laboratory conditions for a limited time. For farming, further field experiments and monitoring of fields where the lime-FeSO4 mixtures are regularly applied can exclude negative long-term effects and determine sufficient the effect of lime-FeSO4 mixtures on bioavailable phosphorus. KW - Phosphorus KW - Liming KW - Bioavailability Y1 - 2018 ER - TY - THES A1 - Höft, Mattis T1 - Influence of humic acids on nutrient use efficiency of three phosphorus sources in a sandy soil N2 - A pot trial was conducted under greenhouse conditions to assess the effect of humic acid (HA) application in combination with rock phosphate (RP) on the plant phosphorus (P) nutrient use efficiency (NUE), in comparison to the performance of struvite (ST) and triple superphosphate (TSP) amended plants. A sandy soil, exhibiting a low P content, was used in combination with a lignite derived, liquid humic acid product, with a HA content of 4.8 %. Nine groups of perennial ryegrass (Lolium perenne L.) were set up as experimental plants, in replications of six, each containing 4.5 kg air dry soil with a P supply of 27 mg P kg-1 soil, causing P deficiency during the experiment. HA was applied at rates of 1, 30 and 100 mg kg-1 soil, directly to the soil as coated RP or as foliar application. Aboveground biomass was harvested biweekly, five times in total. Amendment performance was evaluated by analysing plant biomass, soil pH, plant phosphorus-, carbon-, nitrogen-, iron-, zinc-, manganese- and boron contents. The label doses of 1 mg kg-1 soil as well as 100-fold increases in HA concentration didn’t result in a significant difference in plant shoot or root growth and P NUE compared to untreated plants. Positive trends were displayed at higher foliar application rates. Plant tissue micronutrient concentrations of HA treated samples were generally lower and partly significantly lower than the control. The detected effects were accredited to the hormone-like influence of HA on plants’ metabolism and the ability to alter soil conditions. The lack of calcium in ST amended samples resulted in better plant P availability, significantly higher P uptake and better shoot biomass development. Trends show that ST could be applied in combination with HA to further increase plants P NUE in the future. KW - Humic acid KW - Phosphorus KW - Struvite KW - Rock phosphate KW - Triple superphosphate Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-2978 ER - TY - THES A1 - Paschen, Blanca T1 - Differences in root morphology of modern wheat and barley varieties and their wild ancestors N2 - Sustainable agriculture requires plants which are able to absorb water and nutrients more efficiently to avoid losses and to reduce negative effects on the environment. Root traits are vitally important to fulfill these aims. Therefore, it is important to better understand root morphology of common cereals, such as wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) and their wild relatives. Wild wheat and barley relatives have a superior root system and thus may provide a valuable biological resource for breeding stress tolerant cereals in the future. The objectives of this research were to characterize the variability of root traits among modern wheat and barley cultivars and their wild forms. Fifteen wheat and nine barley cultivars and wild forms were grown under optimal growth conditions without addition of nutrients in a greenhouse experiment. Cultivars and wild forms showed a high genetic variation in root morphology, as well as in shoot traits. Cultivars were divided into three domestication categories: wild forms, old cultivars and modern cultivars. A high variability while comparing cultivars at domestication level showed that it is a 4 weak predictor for root traits. A deep and large root system, high root length density and a high root to shoot ratio were identified as being beneficial traits for efficient nutrient and water uptake. T. aestivum var. tschermakianum, Aegilops cylindrica, H. vulgare hexastichon and H. lagunculiforme had highest values for these traits. Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-1948 ER - TY - THES A1 - Nidola, Marta T1 - Frass upcycling: study on the properties of frass and its use as fertilizer and soil amendment in agriculture N2 - Frass, as by-product of the emerging insect market, has been used as fertiliser worldwide. However, the impacts on soil microbial community structure and activity have been not yet well characterized. The aim of this study was to assess the effects that frass from black soldier fly reared on 3 different diets may cause when applied fresh and dried (70°C) on a sandy loam soil, in 2 application rates (0.2 and 2% w/w). For that, frass was chemically characterized before a 28-days incubation, at the end of which samples were analysed from the chemical and biological point of view. It was found that thermal treatments and diets didn’t vary significantly in microbiota stimulation, even though a chemical analysis would suggest the potential for enriched-frass from pig effluent and wheat bran to encourage microorganisms differently from beer & coffee diet. Furthermore, fresh frass contrarily to what expected didn’t contribute with living microorganisms to enhance microbial activity and growth. However, a difference was reported for the application rates, with the 2% leading to more mineralisation than control. A trend for 2% dried frass from B&C was found, indicating the establishment of an efficient community of fungi slowly mineralizing recalcitrant and exhausted frass. Results indicate that more studies testing application rates ranging between 2 and 2.5% have to be conducted. In fact, there is evidence that BSFF between the mentioned application rates could enhance a fast microbial growth leading to a substantial mineralisation of frass, thus availability of nutrients in the short and long term. Y1 - 2021 ER - TY - THES A1 - Nitsch, Ellen Sophie T1 - Opportunities and challenges of Black Locust (Robinia pseudoacacia L.) as a neophyte in temperate climate zones and potential approaches to management in the case of the urban area of Cleve, Germany. N2 - Black locust (Robinia pseudoacacia L.), a deciduous, nitrogen fixing tree of the family of the Fabaceae, can create opportunities as well as challenges in the areas it is found in. The gathering of information was done in three ways: 1) online research to gather basic information about the species, 2) communication with the Umweltbetriebe Kleve and the Niederrhein forestry office to obtain information about the situation in Cleve, Germany 3) visits to the different black locust stands to get an understanding of the situation. Black locust is a pioneer species with a short life span and is considered as an invasive neophyte in many European countries due to its strong suckering and ability to advance into habitats which then undergo an irreversible change in soil and species composition leading to biodiversity loss in especially threatened habitats such as dry grasslands. This is opposed by black locusts’ strong biomass production, making it well suited for plantation production, resulting in a strong, durable and fast growing multiuse wood as well as nutritious foliage which can be used as animal fodder or for the production of bioenergy. The 9 visited black locust stands situated in and around Cleve, Germany are well established middle-aged stands not used for the production of high value wood. These stands were considered as not threatening to their adjacent environments due to their being surrounded by streets, waterbodies and well maintained fields and parks making a spread unlikely. As the stands are quite old already letting them fade out by natural succession would be the recommended management method. Should the need for removal present itself, girdling would be the suggested technique as, even though it is quite time intensive, it is the least forceful method and thus minimises the possibility of a strong suckering reaction. In conclusion it can be said, that its usage and management system strongly depend on the location and closeness to threatened habitats, considering that, the environmental aspect should always be put before the economic benefits. KW - Robinia pseudoacacia KW - Black locust KW - Invasive neophyte KW - Cleve KW - Opportunities and challenges Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1383-opus4-8720 ER - TY - THES A1 - Ezeobi-Chris, Chimaobi T1 - Quantification of carbon rhizodeposition of different biomes and arable crops from above- and below-ground biomass N2 - As more global warming data become increasingly available, climate change has become one of today’s greatest environmental threats. Terrestrial ecosystem plays an essential part in the uptake of “greenhouse gases (GHGs) such as Nitrous oxide (N2O), Methane (CH4) and Carbon dioxide (CO2)” through photosynthetic sequestration of atmospheric CO2 released from fossil fuel emission, cement manufacturing and deforestation. Rhizodeposits is the released carbon from the root rhizosphere containing a large amount of carbon, essential nutrients and organic compounds. This process is known as rhizodeposition and is often quantified as carbon derived from rhizodeposition (CdfR). This thesis aims to review selected existing literature on above and below-ground biomass carbon (AGB-C and BGB-C) inputs which were used to quantify the carbon sequestration of rhizodeposits in the below-ground biomass (BGB) of different terrestrial ecosystem biomes in the world and to know where the carbon sequestration is lacking the most. Measurement of rhizodeposition in the soil is mostly carried out in the laboratory involving the use of tracing root-derived C by isotopic and non-isotopic techniques, but in this thesis, about 60 papers from different sources were reviewed, and data on above- and below-ground biomass carbon were collected to quantify the C rhizodeposition in the terrestrial ecosystem biomes. The carbon content of the dry weight biomass was estimated by multiplying the above-ground biomass (AGB) and below-ground biomass (BGB) by 0.45. The C-rhizodeposition from the BGB-C was calculated by multiplying the BGB-C by 0.5. Quantification of global C stored in the biomes, including arable crops, was quantified by multiplying the world land area of different biomes with average AGB-C and BGB-C. The estimated values of the mean, median and range of AGB-C, BGB-C and C-rhizodeposition of different biomes (tropical forest, boreal forest, temperate forest, temperate grassland, tropical grassland) and arable crops were reported in this paper. The global C-storage of above- and below-ground of different biomes and arable crops were also quantified. The values were 210, 116, 93, 7.4, 47.2 in Gt C for the tropical forest, boreal forest, temperate forest, temperate grassland, tropical grassland, and 2.4 Gt C for below-ground arable crops only. Even though the comparison between these ecosystems might be an issue because different methods were used in evaluating the above- and below-ground vegetations plant, which in turn can influence the final quantity of C allocated in above- and below-ground biomass, the findings from this thesis for the biomes show that tropical forest has the highest C stored below ground while arable crops have the least. KW - Rhizodeposition KW - Above and below ground KW - Different biomes Y1 - 2021 ER - TY - THES A1 - He, Rushan T1 - Degradation of the herbicide glyphosate in the presence of a second herbicide MCPA as a chemical stressor in agricultural soil N2 - Due to the common agricultural practice of mixing herbicides as well as the long persistence of certain herbicide residues, combinations of herbicides and their residues are often found in soil. These chemicals exert stress on soil microorganisms, affecting the biodegradation of herbicides. There has been little research examining herbicide degradation in the presence of another herbicide from the perspective of stress response using carbon-use efficiency (CUE) to quantify the modified metabolic processes. We investigated, in a 25-day incubation experiment, the effects of the herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA), as an additional chemical stressor for soil microbes, on the degradation of glyphosate, by determining the 13C-labelled glyphosate-derived CO2 (G-derived CO2), 13C-labelled glyphosate incorporated into microbial biomass (G-derived Cmic), and finally the CUE. We observed statistically higher G-derived CO2 in the combined herbicide treatment compared to the treatment with only glyphosate. The G-derived Cmic was lower in the combined treatment than in the glyphosate only treatment, but the difference was not statistically significant. The CUE of soil microorganisms was lower in the combined treatment, but the results were not significant. Despite the statistical insignificance, a clear trend exists that suggests a more catabolic microbial metabolism under stress induced by the presence of a second herbicide MCPA. KW - Pesticide mixtures KW - Glyphosate KW - MCPA KW - Soil microbes KW - Chemical stress and Carbon-use efficiency Y1 - 2021 ER - TY - THES A1 - Gogoi, Nayan jyoti T1 - Combined effects of microplastics and heavy metals: implications for soil microbial ecology N2 - There is substantial evidence that microplastic pollution and heavy metal contamination pose a significant threat to the health of soils and the functioning of ecosystems. However, little is known about the interactions between heavy metals and microplastics, as well as possible biological effects when the two are combined. It is possible that MPs and heavy metals can interact in soil, causing changes in their environmental behaviour, bioavailability, and potentially toxic properties, further posing ecological risks. Therefore, the objective of this study was to evaluate the individual and combined impacts of microplastics and heavy metals on soil chemical properties, microbial biomass, microbial activity, and microbial communities in soil treated with varying concentrations of these pollutants. In an incubation experiment, soil was amended with low-density polyethylene (LDPE) and a mixture of heavy metals (Zn, Cu, and Ni) in two concentrations (Low and High). Seven treatments (Control; MP-L; MP-H; HM-L; HM-H; MP+HM-L and MP+HM-H) were analysed in seven replications. The rate of microbial respiration was determined during incubation. Following incubation, soil pH, microbial biomass carbon (C), nitrogen (N), soil fluorescein diacetate hydrolytic activity, and the abundance of archaea, bacteria, and fungi were measured as well as the effects on inorganic nitrogen (NO3-, NH4+) were determined. It was found that no significant difference existed between the control treatment and LDPE treatment in terms of soil pH, FDAse activity, microbial biomass, microbial respiration, inorganic nitrogen, and abundance of archaea, bacteria, or fungi, regardless of the concentration of LDPE (0.6%, 1.2%). Heavy metal treatment did, however, result in a significant decrease in soil pH, NO3, and microbial respiration particularly at high concentrations (2.68 mg kg-1), compared with treatments with LDPE and a control, suggesting that HMs suppressed microbial activity. Additionally, HMs also reduced MBN and MBC, indicating their negative effect on microbial biomass. As a result of the combination of microplastics and heavy metals, microbial biomass, and microbial respiration decreased significantly when compared to either the control treatments or the microplastics alone treatment. Additionally, the combined treatment reduces NO3- and soil pH significantly compared to the control and sole microplastic treatment There was no significant effect observed in any treatment on the abundance of archaea or fungi, indicating that the presence of MP and/or HMs had no impact on their abundance. However, the MP+HM treatment resulted in a reduction in the number of bacteria. Using a two-factor statistical analysis, the effect of two concentrations (low and high) of microplastics and/or heavy metals on these soil parameters was further evaluated. According to these results, the concentrations of added microplastics and/or heavy metals (low and high) had no significant effect (p > 0.05) on any soil parameter except for soil pH (p < 0.05). Overall, the results indicate that the presence of heavy metals, either alone or combined with microplastics, had a detrimental effect on soil ecosystem. However, this study was limited to examining the short-term effects of these pollutants on soil microorganisms and their functioning. Additional research will be necessary to determine the long-term effects of these pollutants. Y1 - 2023 ER -