Initial Effects of Differently Treated Biogas Residues from Municipal and Industrial Wastes on Spring Barley Yield Formation

Soil application of biogas residues (BGRs) is important for closing nutrient cycles. This study examined the efficiency and impact on yields and yield formation of solid-liquid separated residues from biodegradable municipal and industrial wastes (bio-waste) in comparison to complete BGRs, nitrification inhibitor, agricultural BGRs, mineral fertilizer and unfertilized plots as control. The experiment was set up as a randomized block design on silt loam Cambisol. Biogas residues from four biogas plants were evaluated. Plants per m², ears per plant, grains per ear and thousand grain weight (TGW) were measured at harvest. Fertilization with BGRs resulted in similar biomass yields compared with mineral fertilizer. Mineral fertilizer (71 dt/ha) and plots fertilized with liquid fraction (59–62 dt/ha) indicated a trend to higher yields than solid fraction or complete BGR due to its high ammonia content. Liquid fractions and fraction with nitrification inhibitor induced fewer plants per m² than corresponding solid and complete variants due to a potential phytotoxicity of high NH4-N concentration during germination. However, barley on plots fertilized with liquid fraction compensated the disadvantages at the beginning during the vegetation period and induced higher grain yields than solid fraction. This was attributable to a higher number of ears per plant and grains per ear. In conclusion, BGRs from biodegradable municipal and industrial wastes can be used for soil fertilization and replace considerable amounts of mineral fertilizer. Our study showed that direct application of the liquid fraction of BGR is the most suitable strategy to achieve highest grain yields. Nevertheless potential phytotoxicity of the high NH4-N concentration in the liquid fraction should be considered

A silver impregnation method for motor and sensory nerves and their endings in formalin-fixed mammalian muscles

A silver impregnation method is described which shows motor and sensory nerves and their endings in formalin-fixed mammalian muscles. The method works with the same reliability on flattened muscle pieces as well as on frozen sections. Large nerve bundles, myelinated and non-myelinated single axons, and terminals impregnated by this method stand out black against a light brown background

Nutrient recycling from sanitation and energy systems to the agroecosystem - Ecological research on case studies in Karagwe, Tanzania

Open cycles of organic carbon and nutrients cause soil degradation. Procedures such as ecological sanitation (EcoSan), bioenergy and Terra Preta practice (TPP) can contribute to closing nutrient cycles and may, in addition, sequester carbon. This paper introduces three projects in Karagwe, Tanzania, and their applied approach of integrated resource management to capture carbon and nutrients from different waste flows. Substrates derived from these case studies, biogas slurry, compost and CaSa-compost (containing biochar and sanitized human excreta), were assessed for their nutrient content by analysis of the total element composition. Evaluation focused on potential impacts of the tested amendments on the nutrient availability in the soil as well as on the local soil nutrient balance. Results revealed that all substrates show appropriate fertilizing potential compared to literature, especially for phosphorus (P). CaSa-compost was outstanding, with a total P concentration of 1.7 g dm-3 compared to 0.5 and 0.3 g dm-3 in compost and biogas slurry respectively. Furthermore, these soil amendments may reduce acidity of the soil, with a calculated liming effect of 3.4, 2.6 and 7.8 kg CaO for each kg of nitrogen added for biogas slurry, compost and CaSa-compost respectively. To offset negative P balances in Karagwe, about 8100, 6000 and 1600 dm3 ha-1 are required for biogas slurry, compost and CaSa-compost respectively. We conclude that especially CaSa-compost might offer immediate positive effects to crop production and nutrient availability in the soil

Deep Reinforcement Learning for Heat Pump Control

Heating in private households is a major contributor to the emissions generated today. Heat pumps are a promising alternative for heat generation and are a key technology in achieving our goals of the German energy transformation and to become less dependent on fossil fuels. Today, the majority of heat pumps in the field are controlled by a simple heating curve, which is a naive mapping of the current outdoor temperature to a control action. A more advanced control approach is model predictive control (MPC) which was applied in multiple research works to heat pump control. However, MPC is heavily dependent on the building model, which has several disadvantages. Motivated by this and by recent breakthroughs in the field, this work applies deep reinforcement learning (DRL) to heat pump control in a simulated environment. Through a comparison to MPC, it could be shown that it is possible to apply DRL in a model-free manner to achieve MPC-like performance. This work extends other works which have already applied DRL to building heating operation by performing an in-depth analysis of the learned control strategies and by giving a detailed comparison of the two state-of-the-art control methods

Bodenerosion durch Energiemais – Evaluierung von Erosionsschutzkonzepten mit Erosion-3D

Durch zunehmenden Maisanbau zur Bioenergiegewinnung in Hanglagen erhöht sich die Erosionsgefährdung landwirtschaftlicher Böden. Ziel dieser Studie war deshalb die vergleichende Untersuchung von Erosionsschutzmaßnahmen im Maisanbau unter Verwendung des physikalisch basierten Modells Erosion-3D. Konservierende Bodenbearbeitung (Mulchsaat ohne bzw. mit pflugloser Bodenbearbeitung) zeigte das stärkste Erosionsminderungspotenzial. Kaum Erosionsminderung konnte durch die Anlage von Grünstreifen bzw. durch Begrünung der Abflussrinnen simuliert werden. Eine mittlere Erosionsminderung konnte durch die Unterteilung des Feldes in kleinere Parzellen oder Streifen (abwechselnd Mais- und Wintergetreideanbau) gezeigt werden

Contrasting effects of biochar on N2O emission and N uptake at different N fertilizer levels on a temperate sandy loam

Biochar has been frequently suggested as an amendment to improve soil quality and mitigate climate change. To investigate the optimal management of nitrogen (N) fertilization, we examined the combined effect of biochar and N fertilizer on plant N uptake and N2O emissions in a cereal rotation system in a randomized two-factorial field experiment on a sandy loam soil in Brandenburg, Germany. The biochar treatment received 10 Mg ha− 1 wood-derived biochar in September 2012. Four levels of N fertilizer, corresponding to 0, 50%, 100%, 130% of the recommended fertilizer level, were applied in winter wheat (Triticum aestivum L.)) and winter rye (Secale cereal L.) in 2013 and 2014 followed by the catch crop oil radish (Raphanus sativus L. var. oleiformis). Biomass and N uptake of winter wheat and winter rye were significantly affected by the level of N fertilizer but not by biochar. For N uptake of oil radish an interaction effect was observed for biochar and N fertilizer. Without applied fertilizer, 39% higher N uptake was found in the presence of biochar, accompanied by higher soil NH4+ content and elevated cumulative CO2 emissions. At 130% of the recommended fertilizer level, 16% lower N uptake and lower cumulative N2O emissions were found in the biochar-mediated treatment. No significant change in abundance of microbial groups and nosZ gene were observed. Our results highlight that biochar can have a greenhouse gas mitigation effect at high levels of N supply and may stimulate nutrient uptake when no N is supplied

Contrasting effects of biochar on N2O emission and N uptake at different N fertilizer levels on a temperate sandy loam

Biochar has been frequently suggested as an amendment to improve soil quality and mitigate climate change. To investigate the optimal management of nitrogen (N) fertilization, we examined the combined effect of biochar and N fertilizer on plant N uptake and N2O emissions in a cereal rotation system in a randomized two-factorial field experiment on a sandy loam soil in Brandenburg, Germany. The biochar treatment received 10 Mg ha− 1 wood-derived biochar in September 2012. Four levels of N fertilizer, corresponding to 0, 50%, 100%, 130% of the recommended fertilizer level, were applied in winter wheat (Triticum aestivum L.)) and winter rye (Secale cereal L.) in 2013 and 2014 followed by the catch crop oil radish (Raphanus sativus L. var. oleiformis). Biomass and N uptake of winter wheat and winter rye were significantly affected by the level of N fertilizer but not by biochar. For N uptake of oil radish an interaction effect was observed for biochar and N fertilizer. Without applied fertilizer, 39% higher N uptake was found in the presence of biochar, accompanied by higher soil NH4+ content and elevated cumulative CO2 emissions. At 130% of the recommended fertilizer level, 16% lower N uptake and lower cumulative N2O emissions were found in the biochar-mediated treatment. No significant change in abundance of microbial groups and nosZ gene were observed. Our results highlight that biochar can have a greenhouse gas mitigation effect at high levels of N supply and may stimulate nutrient uptake when no N is supplied

Environmental Effects over the First 2 1/2 Rotation Periods of a Fertilised Poplar Short Rotation Coppice

A short rotation coppice (SRC) with poplar was established in a randomised fertilisation experiment on sandy loam soil in Potsdam (Northeast Germany). The main objective of this study was to assess if negative environmental effects as nitrogen leaching and greenhouse gas emissions are enhanced by mineral nitrogen (N) fertiliser applied to poplar at rates of 0, 50 and 75 kg N ha−1 year−1 and how these effects are influenced by tree age with increasing number of rotation periods and cycles of organic matter decomposition and tree growth after each harvesting event. Between 2008 and 2012, the leaching of nitrate (NO3 −) was monitored with self-integrating accumulators over 6-month periods and the emissions of the greenhouse gases (GHG) nitrous oxide (N2O) and carbon dioxide (CO2) were determined in closed gas chambers. During the first 4 years of the poplar SRC, most nitrogen was lost through NO3 − leaching from the main root zone; however, there was no significant relationship to the rate of N fertilisation. On average, 5.8 kg N ha−1 year−1 (13.0 kg CO2equ) was leached from the root zone. Nitrogen leaching rates decreased in the course of the 4-year study parallel to an increase of the fine root biomass and the degree of mycorrhization. In contrast to N leaching, the loss of nitrogen by N2O emissions from the soil was very low with an average of 0.61 kg N ha−1 year−1 (182 kg CO2equ) and were also not affected by N fertilisation over the whole study period. Real CO2 emissions from the poplar soil were two orders of magnitude higher ranging between 15,122 and 19,091 kg CO2 ha−1 year−1 and followed the rotation period with enhanced emission rates in the years of harvest. As key-factors for NO3 − leaching and N2O emissions, the time after planting and after harvest and the rotation period have been identified by a mixed effects model

Einfluss pyrogener Kohle auf den Stoffhaushalt tropischer Böden in Mosambik

Die Einarbeitung von pyrogener Kohle in Verbindung mit organischem Dünger in nährstoffarme tropische Böden birgt ein Potenzial zur Ertragsteigerung in der Landwirtschaft. In einem zweimonatigen Parzellenversuch auf einer Jatropha-Plantage in Zentral Mosambik wurde der Einfluss von Biokohle und Grasschnitt auf den Nährstoffhaushalt zweier Böden, die sich deutlich in Ton- und C-Gehalt unterscheiden, getestet: Ein sandiger, C-ärmerer Stagnosol und ein lehmiger C reicherer Luvisol. Auf dem Stagnosol wurde eine deutliche Verbesserung der P- und K-Verfügbarkeit im Boden, eine Erhöhung des pH-Wertes und eine Steigerung der Jatropha-Blattgehalte an P, K, Mg, N und S erreicht, allerdings noch keine Ertragssteigerung. Auf dem bereits fruchtbaren lehmigen Luvisol war die Biokohle Zugabe dort nicht lohnenswert Aufgrund des höheren Ton- und C-Gehalts gab es nur geringe Effekte. Für nährstoffarme, sandige Böden bleibt eine längerfristige, nachhaltige Wirkung der Biokohle-Effekte zu prüfen