Browsing by Subject "Potato"

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Agrivoltaic system impacts on microclimate and yield of different crops within an organic crop rotation in a temperate climate
(2021) Weselek, Axel; Bauerle, Andrea; Hartung, Jens; Zikeli, Sabine; Lewandowski, Iris; Högy, Petra
Agrivoltaic (AV) systems integrate the production of agricultural crops and electric power on the same land area through the installation of solar panels several meters above the soil surface. It has been demonstrated that AV can increase land productivity and contribute to the expansion of renewable energy production. Its utilization is expected to affect crop production by altering microclimatic conditions but has so far hardly been investigated. The present study aimed to determine for the first time how changes in microclimatic conditions through AV affect selected agricultural crops within an organic crop rotation. For this purpose, an AV research plant was installed near Lake Constance in south-west Germany in 2016. A field experiment was established with four crops (celeriac, winter wheat, potato and grass-clover) cultivated both underneath the AV system and on an adjacent reference site without solar panels. Microclimatic parameters, crop development and harvestable yields were monitored in 2017 and 2018. Overall, an alteration in microclimatic conditions and crop production under AV was confirmed. Photosynthetic active radiation was on average reduced by about 30% under AV. During summertime, soil temperature was decreased under AV in both years. Furthermore, reduced soil moisture and air temperatures as well as an altered rain distribution have been found under AV. In both years, plant height of all crops was increased under AV. In 2017 and 2018, yield ranges of the crops cultivated under AV compared to the reference site were −19 to +3% for winter wheat, −20 to +11% for potato and −8 to −5% for grass-clover. In the hot, dry summer 2018, crop yields of winter wheat and potato were increased by AV by 2.7% and 11%, respectively. These findings show that yield reductions under AV are likely, but under hot and dry weather conditions, growing conditions can become favorable.
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.
Microbial consortia versus single-strain inoculants as drought stress protectants in potato affected by the form of N supply
(2024) Mamun, Abdullah Al; Neumann, Günter; Moradtalab, Narges; Ahmed, Aneesh; Dupuis, Brice; Darbon, Geoffrey; Nawaz, Fahim; Declerck, Stephane; Mai, Karin; Vogt, Wolfgang; Ludewig, Uwe; Weinmann, Markus
This study investigated the drought protection effects of six fungal and bacterial inoculants and ten consortia thereof on vegetative growth, nutritional status, and tuberization of potato under controlled and field conditions. It was hypothesized that microbial consortia offer improved drought protection as compared with single strains, due to complementary or synergistic effects, with differential impacts also of N fertilization management. Under NO3− fertilization, a 70% reduction in water supply over six weeks reduced shoot and tuber biomass of non-inoculated plants by 30% and 50%, respectively, and induced phosphate (P) limitation compared to the well-watered control. The P nutritional status was significantly increased above the deficiency threshold by three single-strain inoculants and eight consortia. This was associated with the presence of the arbuscular mycorrhizal fungus (AMF) inoculant Rhizophagus irregularis MUCL41833 (five cases) and stimulation of root growth (five cases). Additionally, Bacillus amyloliquefaciens FZB42 and AMF + Pseudomonas brassicacearum 3Re2-7 significantly reduced irreversible drought-induced leaf damage after recovery to well-watered conditions. However, the microbial inoculants did not mitigate drought-induced reductions in tuber biomass, neither in greenhouse nor in field experiments. By contrast, NH4+-dominated fertilization significantly increased tuber biomass under drought stress (534%), which was further increased by additional AMF inoculation (951%). This coincided with (i) improved enzymatic detoxification of drought-induced reactive oxygen species (ROS), (ii) improved osmotic adjustment in the shoot tissue (glycine betaine accumulation), (iii) increased shoot concentrations of ABA, jasmonic acid, and indole acetic acid, involved in drought stress signaling and tuberization, and (iv) reduced irreversible drought-induced leaf damage. Additional application of bacterial inoculants further improved ROS detoxification by increasing the production of antioxidants but stimulated biomass allocation towards shoot growth at the expense of tuber development. The results demonstrated that microbial consortia could increase the probability of drought protection effects influenced by the form of N supply. However, protective effects on vegetative growth do not necessarily translate into yield benefits, which can be achieved by adequate combination of inoculants and fertilizers.