Browsing by Subject "Short rotation coppice"

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Agrarökonomische Analyse von Verfahren zur Erzeugung lignozellulosehaltiger Biomasse und deren Akzeptanz in der Landwirtschaft Baden-Württembergs
(2018) Gillich, Caroline Sophie-Theresia; Lippert, Christian
In a future bio-based economy, agricultural production of renewable raw materials for the production of plant biomass is supposed to play a central role. This also includes the perennial crops short rotation coppice (SRC) and miscanthus. A material utilization, particularly of the produced lignocellulose, in chemical industry can contribute to a bio-based economic activity. However, the cultivation of SRC and miscanthus is not yet widespread. For a variety of reasons, such as lack of knowledge or low profitability, farmers have not strongly implemented these crops so far. To find out, which factors do have an impact on the cultivation of SRC and miscanthus, farmer workshops with surveys were conducted in selected regions of Baden-Wuerttemberg. Additionally, by means of a choice experiment, the preferences of the farmers for the cultivation of SRC and miscanthus were elicited. As the introduction of new production methods is often linked to increased risks, in addition the risk attitude of the farmers was determined by means of a “Holt and Laury” lottery. The surveys took place in the Vergleichsgebietsgruppen (VGG) „Unterland / Gaeue“, „Rhine / Lake Constance“ and „Bauland / Hohenlohe“ in Baden-Wuerttemberg. For all VGG site specific profitability and risk analyses were performed. The mentioned VGG were identified as most suitable for SRC and miscanthus. In total, 117 farmers participated in nine organized workshops. In the surveyed sample more farmers are cultivating SRC than in the entire farmer population. For the analysis of the choice experiment Random Parameter Logit Models were used. The following results are to be interpreted under ceteris paribus conditions. Generally, the part-worth utility of the cultivation of SRC and miscanthus is negative. Additionally to the opportunity costs of land, the expected average compensation payments amount to € 460 and € 400 per hectare and year for SRC and miscanthus. However, in this context farmers do not significantly distinguish between the two perennial crops. As expected an increasing profitability of these production activities increases the utility, whereas an increasing variability of contribution margins and increasing investment costs reduce the utility. It should be noted that a guaranteed purchase contract for the harvested crop over the whole cultivation period increases the utility of the permanent crops at a significant level. Through this the negative part-worth utility of SRC or miscanthus could be compensated almost completely. If colleagues in the near surrounding already cultivate these crops, this also increases the utility. Among the respondents a significant preference heterogeneity exists for both production activities and all attributes considered in the choice experiment. Further model estimations with interaction terms to explain part of the heterogeneity show that, among other things, an increasing farm size has a negative impact on the probability of cultivating SRC. An increasing age of the farm manager also reduces the utility of the cultivation of SRC and miscanthus. An increasing work experience has a positive effect on the probability of choosing SRC. Moreover, an increase of the initial investment cost reduces the utility of the participants the more, the more risk averse they are. In this context, the implicitly assumed interest rates, deduced from the model and assuming a farmer with average risk attitude, are in a realistic range between 2.3 % and 4.1 %. Based on the estimated part-worth utility distribution parameters of the model without interaction terms, finally supply functions were derived by means of Monte Carlo simulations, to illustrate cultivation potentials of SRC and miscanthus at various wood chip prices and for different scenarios. The potentials of SRC and miscanthus estimated this way are more realistic than former GIS-based potentials as not only location factors but also empirically found preferences of the farmers and opportunity costs of farmland were taken into account. Under the assumptions made, the maximum expectable potential of SRC and miscanthus on arable land in the surveyed region amounts in each case to 30,000 hectares. It should be noticed, that this cultivation potential is relatively low. The results of the choice experiment show that - as long as this is considered to be justified from an economic point of view - either a direct subsidy by the government, the cultivation in clusters or purchase guarantees for the farmers by the processing industry can strongly promote the cultivation of perennial lignocellulose containing crops.
Managing trees on arable land
(2020) Schulz, Vanessa Sarah; Graeff-Hönninger, Simone
The cultivation of several plant species on the same area of land, at the same time, is called Agroforestry (AFS). In the less developed countries and the countries of the tropics and subtropics, AFS are the main form of land management. Reasons can be found in the low degree of mechanization and the low costs of labor. AFS used to be widespread in the industrial nations, too. Over the years, however, these traditional forms have been converted into highly efficient agricultural sites. Agricultural and forest production has been separated spatially. In Germany, this was mainly due to land consolidation, which resulted in large, uniform, and easy-to-farm fields. In recent years, however, this situation has been reconsidered. The positive environmental benefits and the aspect of biodiversity protection of agroforestry systems have been recognized. There are numerous ecological, economic, and social aspects, which make agroforestry attractive again. However, a competitive situation always arises when plants are cultivated together. In addition, there are multiple forms of AFS. Special attention must be paid to the planting of the woody, perennial component, as it remains on the field for several years. Against this background, this thesis deals with the possibilities of establishing the wood component in an AFS as a short rotation strip. Combinations of different tillage and weed management practices on willow growth and yield were tested. Furthermore, the influence of shade, which is listed as one of the three main influencing factors in AFS, is discussed. Agricultural crops behave differently, on shade casts by the woody component on the understory crop, depending on their need for light. To test this, maize was used as a shade-intolerant C4 plant, which reaches its light saturation close to maximum solar irradiance. In contrast, potato was tested as a more shade-tolerant C3 plant. Observations on growth, yield and quality should provide information on their suitability for cultivation under shady conditions in AFS. Various hypotheses were developed and examined for the purpose of testing. In the following, the most central research results will be briefly outlined. When establishing a short rotation coppice with willows, an adequate combination of soil tillage and weed management showed to be important for high yields, whereas the necessary weed management depends on the used soil tillage. Until today, there are no other recommendations for the establishment of a willow short-rotation coppice except ploughing in autumn, harrowing in spring and broad herbicide application. In the current discourse on biodiversity improvement and climate change, forms of reduced tillage (chisel plough + ley crop, no-till) with adapted herbicide-saving weed control (e.g. chemical treatment within the rows and mechanical treatment between the rows, or only mechanical weed control), were tested as alternatives that ensure successful SRC growth and, as a result, high yields while saving pesticides and fossil energy. When grown together, trees will shade the under-story agricultural crops. Some crops can deal better with this light reduction than others. Maize (Zea mays L.), as a plant with a high light saturation point, is already negatively influenced in its growth, the biomass, biogas, and methane yield, as well as the quality determining compounds (dry matter content, crude protein, crude ash) by low amounts of shade. While potatoes (Solanum tuberosum L.), known as shade-tolerant plants, can produce yields and qualities comparable to those of unshaded plants with lower levels of solar irradiance (caused by shading). It could be shown that it is possible to make a valuable contribution to biodiversity with AFS. By using adapted combinations of soil tillage and weed management systems, fossil fuels can be saved through reduced tillage. The use of chemical plant protection in the tree strips can be reduced by the sole application within the SRC strips or avoided altogether by mechanical weed control. In high-valuable timber systems there is usually no weed management necessary. Additionally, the trees strips offer a habitat and food basis for small vertebrates and some arthropods (hymenoptera, coleoptera, lepidoptera and diptera). The permanent planting of the strips reduces greenhouse gases and thus counteracts climate change. Influences of shade on crop yield and quality was only proven for plant-specific shade levels. In such AFS, the influence of shade usually only occurs in later tree ages (and crown thickness). Therefore, AFS are a valuable form of land management to reduce current environmental problems on a national and global scale, while adequate yields can be achieved at the same time.