Nitrification inhibitors reduce N2O emissions induced by application of biogas digestate to oilseed rape

Winter oilseed rape (WOSR) is the major oil crop cultivated in Europe and the most important feedstock for biodiesel. Up to 90% of the greenhouse gas (GHG) emissions from biodiesel production can occur during oilseed rape cultivation. Therefore, mitigation strategies are required and need to focus on direct nitrous oxide (N2O) emission as one of the largest GHG contributors in biodiesel production. Earlier studies show that nitrification inhibitors (NIs) can reduce N2O emissions derived from N-fertilization. Since information on the effect of biogas digestates with or without NIs on N2O emissions from WOSR fields is scarce, the aim of this study was to evaluate their effects on N2O emissions, mineral N dynamics, and oil yield in WOSR production fertilized with digestate. The study was conducted at five sites across Germany over three years resulting in 15 full site-years data sets. Across all sites and years, N2O emission from WOSR fertilized with biogas digestate (180 kg NH4+-N ha−1yr−1) ranged between 0.2 and 3.5 kg N2O–N ha−1 yr−1. Due to the reduction of the nitrate concentrations following digestate application, application of NI significantly reduced annual N2O emission by 36%. Our results demonstrate that NI can be an effective measure for reducing N2O emissions from digestate application, but its effectiveness depends on soil and weather conditions, and ultimately on the site-specific potential for N2O production and release. There was no effect of NI application on grain and oil yield.Bundesministerium für Ernährung und Landwirtschaft (DE)Universität Hohenheim (3153)Peer Reviewe

Spot farming – an alternative for future plant production

Das Ziel der nachhaltigen Intensivierung der Landwirtschaft ist die Steigerung der weltweiten Nahrungsmittelproduktion bei gleichzeitiger Reduzierung des Inputs sowie der Vermeidung von negativen Umwelteinflüssen. Wachsende Kritik an den derzeitigen Produktionssystemen sowie der demografische Wandel, der mit einem zunehmenden Arbeitskräftemangel in den ländlichen Räumen einhergeht, stellen weltweit eine zunehmende Herausforderung für die Landwirtschaft dar. Im Rahmen dieses Problemfeldes bieten die Digitalisierung und auto­nome Maschinensysteme neue Möglichkeiten um die Landwirtschaft an diese Herausforderungen anzupassen. Bisher ist nicht bekannt, welche Veränderungen zur Errei­chung einer nachhaltigen Intensivierung im Gesamt­system Pflanzenproduktion notwendig sind und wie die Landwirtschaft der Zukunft unter Einbeziehung neuer technologischer Möglichkeiten aussehen könnte.Im Rahmen dieser Arbeit wurde ein Konzept für zukünf­tige Pflanzenbausysteme unter Berücksichtigung der Kulturpflanzenansprüche und des Landschaftskontextes entwickelt. Hierbei werden die Agrarflächen nach unterschiedlichen teilflächenspezifischen Eigenschaften bewertet und darauf aufbauend in unterschiedlichen Spots reorganisiert. Das daraus abgeleitete Konzept des Spot-Farmings basiert auf einer vollständigen Bewirtschaftung mit autonomen Robotiksystemen auf Einzelpflanzenebene. Durch höhere Präzision bei Aussaat, Düngungs- und Pflanzenschutzmaßnahmen können Ressour­cen gespart und Erträge gesteigert werden. Kleine Robotersysteme können zudem einen Beitrag zum Boden­schutz leisten. Das Spot-Farming-Konzept berücksichtigt darüber hinaus die natürlichen Landschafts­eigenschaften, um gesellschaftlich erwünschte Neben­aspekte, wie vielfältigere Kulturlandschaften, mehr Biodiversität und Struktur in der Landschaft, zu berücksichtigen.Die Bewertung des Konzepts nach pflanzenbaulichen, technischen und ökonomischen Aspekten zeigt, dass die Kombination von modernen Technologien und einer Reorga­nisierung der Kulturlandschaften zum Ziel der nachhaltigen Intensivierung beitragen kann.Sustainable intensification is described as the desirable goal for agricultural production to increase agricultural productivity while using less input and without adverse environmental impacts. Increasing criticism on current agricultural production systems as well as demographic changes related with labour shortages in rural areas pose major challenges to agriculture all over the world. In this context, digitalization and autonomous machinery provide new opportunities to adapt agriculture to future demands. However, it is unknown what changes are necessary for a sustainable intensification of cropping systems and how future agriculture could look like under consideration of new technologies.Here we developed a concept for future cropping systems with focus on the requirements of crops and landscapes. In this concept, the agricultural area is classified into individual spots according to their site-specific characteristics. The resulting spot farming approach is completely managed by an autonomous robot system on the level of individual plants. High precision sowing, fertilization and pesticide application could reduce agronomic input and could increase yields. In addition, small robots contribute to soil protection. Furthermore, the spot farming approach considers landscape properties and has the potential for a higher biodiversity and more structural ele­ments as well as an increased social acceptance.The evaluation of the concept according to agronomical, technical and economic aspects showed that the combination of modern technologies and a reorganisation of agricultural landscapes could contribute to the goal of sustainable intensification

Optimized seed patterns in cereals

Ein optimiertes Aussaatmuster mit gleichmäßigen Abständen zwischen den Pflanzen erhöht den nutzbaren Stand­raum je Einzelpflanze und reduziert intraspezifische Konkurrenzeffekte. Neben höheren und stabileren Erträgen sind auch Vorteile hinsichtlich Ressourcennutzungseffizienz, Stresstoleranz und Unkrautunterdrückungsvermögen zu erwarten. Aktuell wird Getreide vorwiegend in Drillsaat ausgebracht, was nicht dem pflanzenbaulichen Optimum entspricht, jedoch eine hohe Flächenleistung ermöglicht. Alternativ ist für die Getreideaussaat reihenabhängige Einzelkornsätechnik verfügbar, welche bereits deutliche Vorteile hinsichtlich eines gleichmäßigeren Saatbilds zeigt. Den gleichmäßigsten Standraum je Einzelpflanze erreicht man mit einer Gleichstandsaat im Dreieckverband, welche bei Getreide technisch noch nicht realisierbar ist. Um die erwarteten Vorteile der Gleichstandsaat bei Getreide zu überprüfen, werden am Julius Kühn-Institut Versuche zur Gleichstandsaat bei Winterweizen durchgeführt, um Fragestellungen hinsichtlich Ertrag, Ressourcennutzungseffizienz, Stresstoleranz etc. zu beantworten. Parallel dazu sind die Anpassung einer Einzelkornsämaschine sowie die Entwicklung eines mobilen autonomen Systems geplant, die eine Aussaat im Dreieckverband ermöglichen.An optimized seed pattern with even distances increases the utilizable space of individual plants and reduces intraspecific competition. In addition to higher and more stable yields, benefits in terms of resource use efficiency, stress tolerance and weed suppression are expected. Currently, cereals are mainly sown in rows, which does not corres­pond to the crops’ optimum, but allows a fast sowing. Alternatively, precision seeding is available for cereals, which already allows a more uniform seed pattern. The most even spacing per single plant can be achieved with a uniform seed pattern in a triangular lattice, which is technically not yet feasible in cereals. In order to test the expected benefits of a uniform seed pattern in cereals, field trials are conducted at the JKI with winter wheat to answer questions regarding yield, resource use efficiency and stress tolerance. At the same time, the adaptation of a precision seeding and the development of an autonomous sowing system are planned in order to enable a uniform seed pattern

Nitrous oxide emissions from winter oilseed rape cultivation

Winter oilseed rape (Brassica napus L., WOSR) is the major oil crop cultivated in Europe. Rapeseed oil is predominantly used for production of biodiesel. The framework of the European Renewable Energy Directive requires that use of biofuels achieves GHG savings of at least 50% compared to use of fossil fuel starting in 2018. However, N2O field emissions are estimated using emission factors that are not specific for the crop and associated with strong uncertainty. N2O field emissions are controlled by N fertilization and dominate the GHG balance of WOSR cropping due to the high global warming potential of N2O. Thus, field experiments were conducted to increase the data basis and subsequently derive a new WOSR-specific emission factor. N2O emissions and crop yields were monitored for three years over a range of N fertilization intensities at five study sites representative of German WOSR production. N2O fluxes exhibited the typical high spatial and temporal variability in dependence on soil texture, weather and nitrogen availability. The annual N2O emissions ranged between 0.24 kg and 5.48 kg N2O-N ha−1 a−1. N fertilization increased N2O emissions, particularly with the highest N treatment (240 kg N ha−1). Oil yield increased up to a fertilizer amount of 120 kg N ha−1, higher N-doses increased grain yield but decreased oil concentrations in the seeds. Consequently oil yield remained constant at higher N fertilization. Since, yield-related emission also increased exponentially with N surpluses, there is potential for reduction of the N fertilizer rate, which offers perspectives for the mitigation of GHG emissions. Our measurements double the published data basis of annual N2O flux measurements in WOSR. Based on this extended dataset we modeled the relationship between N2O emissions and fertilizer N input using an exponential model. The corresponding new N2O emission factor was 0.6% of applied fertilizer N for a common N fertilizer amount under best management practice in WOSR production (200 kg N ha−1 a−1). This factor is substantially lower than the linear IPCC Tier 1 factor (EF1) of 1.0% and other models that have been proposed. © 201