Simulating Root Growth as a Function of Soil Strength and Yield With a Field-Scale Crop Model Coupled With a 3D Architectural Root Model

Accurate prediction of root growth and related resource uptake is crucial to accurately simulate crop growth especially under unfavorable environmental conditions. We coupled a 1D field-scale crop-soil model running in the SIMPLACE modeling framework with the 3D architectural root model CRootbox on a daily time step and implemented a stress function to simulate root elongation as a function of soil bulk density and matric potential. The model was tested with field data collected during two growing seasons of spring barley and winter wheat on Haplic Luvisol. In that experiment, mechanical strip-wise subsoil loosening (30–60 cm) (DL treatment) was tested, and effects on root and shoot growth at the melioration strip as well as in a control treatment were evaluated. At most soil depths, strip-wise deep loosening significantly enhanced observed root length densities (RLDs) of both crops as compared to the control. However, the enhanced root growth had a beneficial effect on crop productivity only in the very dry season in 2018 for spring barley where the observed grain yield at the strip was 18% higher as compared to the control. To understand the underlying processes that led to these yield effects, we simulated spring barley and winter wheat root and shoot growth using the described field data and the model. For comparison, we simulated the scenarios with the simpler 1D conceptual root model. The coupled model showed the ability to simulate the main effects of strip-wise subsoil loosening on root and shoot growth. It was able to simulate the adaptive plasticity of roots to local soil conditions (more and thinner roots in case of dry and loose soil). Additional scenario runs with varying weather conditions were simulated to evaluate the impact of deep loosening on yield under different conditions. The scenarios revealed that higher spring barley yields in DL than in the control occurred in about 50% of the growing seasons. This effect was more pronounced for spring barley than for winter wheat. Different virtual root phenotypes were tested to assess the potential of the coupled model to simulate the effect of varying root traits under different conditions.Peer Reviewe

Beet harvesting technology – current status and developments

Der Zuckerrübenanbau hat nicht an Bedeutung verloren. Dies zeigen sowohl die statistischen Zahlen als auch die Aktivitäten im Bereich der Zuckerrübenerntetechnik. Eine Konzentration auf wenige Hersteller ist festzustellen. Die Schwerpunkte bei diesen sind Detailverbesserungen zur Prozessüberwachung und Assistenzsysteme. Eine automatisierte und bestandsabhängige Einstellung der Köpf-Rodegruppe sowie durchsatzabhängige Rübenbehandlung sind hier zu nennen. Telematik und gesteigerter Bedienkomfort sind weitere Aspekte.Sugar beet cultivation has not lost any of its importance. This is shown by statistics, but also by the activities in the area of sugar beet harvesting technology. There is a concentration on just a few manufacturers. These focus on detailed improvements to process monitoring and assistance systems. Automated, crop-adapted adjustment of the harvesting group and throughput-dependent beet treatment are worth mentioning here. Telematic and increased ease of operation are further aspects

Beet harvesting technology - current status and developments

Der Zuckerrübenanbau hat weiterhin ein hohes Anbauvolumen. Bei der Erntetechnik haben Detailverbesserungen in allen Bereichen stattgefunden. Betriebssicherheit und Funktionsoptimierungen beim Roden und die Übersicht über relevante Prozessdaten, aber auch die Gestaltung eines komfortablen Arbeitsplatzes stehen im Fokus. Möglichkeiten der Betriebskostensenkung durch geringeren Verschleiß der Bauteile, aber auch Einsparungen beim Verbrauch von Betriebsmitteln bieten dem Landwirt die Möglichkeit Stückkosten weiter zu senken.The volume of sugar beet cultivation remains high. Detailed improvements have been made in all areas of sugar beet harvesting technology. The focus is on operational safety and functional optimization during harvesting, as well as the design of a comfortable workplace and an overview of all relevant process data. Opportunities to reduce operating costs by minimizing wear and tear on all components, but also by saving on the consumption of operating resources, offer the farmer the opportunity to reduce unit costs

A True-Color Sensor and Suitable Evaluation Algorithm for Plant Recognition

Plant-specific herbicide application requires sensor systems for plant recognition and differentiation. A literature review reveals a lack of sensor systems capable of recognizing small weeds in early stages of development (in the two- or four-leaf stage) and crop plants, of making spraying decisions in real time and, in addition, are that are inexpensive and ready for practical use in sprayers. The system described in this work is based on free cascadable and programmable true-color sensors for real-time recognition and identification of individual weed and crop plants. The application of this type of sensor is suitable for municipal areas and farmland with and without crops to perform the site-specific application of herbicides. Initially, databases with reflection properties of plants, natural and artificial backgrounds were created. Crop and weed plants should be recognized by the use of mathematical algorithms and decision models based on these data. They include the characteristic color spectrum, as well as the reflectance characteristics of unvegetated areas and areas with organic material. The CIE-Lab color-space was chosen for color matching because it contains information not only about coloration (a- and b-channel), but also about luminance (L-channel), thus increasing accuracy. Four different decision making algorithms based on different parameters are explained: (i) color similarity (ΔE); (ii) color similarity split in ΔL, Δa and Δb; (iii) a virtual channel ‘d’ and (iv) statistical distribution of the differences of reflection backgrounds and plants. Afterwards, the detection success of the recognition system is described. Furthermore, the minimum weed/plant coverage of the measuring spot was calculated by a mathematical model. Plants with a size of 1–5% of the spot can be recognized, and weeds in the two-leaf stage can be identified with a measuring spot size of 5 cm. By choosing a decision model previously, the detection quality can be increased. Depending on the characteristics of the background, different models are suitable. Finally, the results of field trials on municipal areas (with models of plants), winter wheat fields (with artificial plants) and grassland (with dock) are shown. In each experimental variant, objects and weeds could be recognized

Assessing Subsoil Conditions with an ASABE Conform Vertical Penetrometer—Development and Evaluation

Soil is the habitat for soil organisms and associated soil physical and chemical processes. The subsoil is a large reserve of water and nutrients. Soil and subsoil are thus significantly involved in the yield capacity of a site and its resilience in the case of unfavorable weather conditions. Subsoil can also retain water in drought phases and stores carbon. In times of climate change and scarcity of resources, many scientific activities involve subsoil and require sensors to assess subsoil conditions and properties. An electrically driven penetrometer with an integrated soil water content sensor could be an appropriate tool for such applications; however, such a subsoil measurement tool does not exist. One major reason for this is that, when penetrating compacted subsoil, high penetration forces (including friction) act on the penetrating thin rod (diameter 1 cm). The development of a tractor-mounted subsoil penetrometer for depths up to 2 m is described in this study. An ASABE standard cone is implemented, which can access heavy compacted layers. The rod, which includes wires for embedding an FDI moisture sensor in the cone tip, is covered by a protection tube. The penetration resistance measurement can be performed without being influenced by shaft friction. The rod, along with the sensor, is implemented in a tower that can be shifted laterally and can take probes in a single line without moving the tractor. To confirm the quality of the developed subsoil penetrometer, a suitable evaluation method is presented. Typical arable soil (loamy silt) was filled in boxes and compacted homogeneously using a hydraulic stamp so that different setups of the penetrometer could be compared and evaluated. The evaluation concludes that the distance between the free cone tip and the protection shaft should be at least 10 cm to measure the penetration resistance of soil without being influenced by the protection tube. Furthermore, the developed penetrometer has sufficient stability and precision for accessing subsoil. In field trials, the subsoil penetrometer was compared with a standard penetrometer and has proved its suitability

Assessing Subsoil Conditions with an ASABE Conform Vertical Penetrometer—Development and Evaluation

Soil is the habitat for soil organisms and associated soil physical and chemical processes. The subsoil is a large reserve of water and nutrients. Soil and subsoil are thus significantly involved in the yield capacity of a site and its resilience in the case of unfavorable weather conditions. Subsoil can also retain water in drought phases and stores carbon. In times of climate change and scarcity of resources, many scientific activities involve subsoil and require sensors to assess subsoil conditions and properties. An electrically driven penetrometer with an integrated soil water content sensor could be an appropriate tool for such applications; however, such a subsoil measurement tool does not exist. One major reason for this is that, when penetrating compacted subsoil, high penetration forces (including friction) act on the penetrating thin rod (diameter 1 cm). The development of a tractor-mounted subsoil penetrometer for depths up to 2 m is described in this study. An ASABE standard cone is implemented, which can access heavy compacted layers. The rod, which includes wires for embedding an FDI moisture sensor in the cone tip, is covered by a protection tube. The penetration resistance measurement can be performed without being influenced by shaft friction. The rod, along with the sensor, is implemented in a tower that can be shifted laterally and can take probes in a single line without moving the tractor. To confirm the quality of the developed subsoil penetrometer, a suitable evaluation method is presented. Typical arable soil (loamy silt) was filled in boxes and compacted homogeneously using a hydraulic stamp so that different setups of the penetrometer could be compared and evaluated. The evaluation concludes that the distance between the free cone tip and the protection shaft should be at least 10 cm to measure the penetration resistance of soil without being influenced by the protection tube. Furthermore, the developed penetrometer has sufficient stability and precision for accessing subsoil. In field trials, the subsoil penetrometer was compared with a standard penetrometer and has proved its suitability

Strip-till seeder for sugar beets

Strip-till save costs by reducing tillage on the area of sugar beet rows only. The seeding system is characterized by a deep loosening of soil with a tine combined with a share and by following tools generating fine-grained soil as seed bed. In cooperation with the Kverneland company group Soest/Germany a strip tiller combined with precision seeder was designed and tested in field experiments. Tilling and seeding was performed in one path on fields with straw and mustard mulch. Even the plant development was slower as compared to conventional sawn sugar beets the yield was on equivalent level. Further field experiments are planned to attest constant yield, cost and energy efficiency of the seeding system

Subsoil Melioration with Organic Material—Principle, Technology and Yield Effects

An increasing challenge for agriculture in times of climate change is to sustainably ensure or increase the yield capacity of crop production. Low-yielding sites are particularly at risk in this respect. One strategy to counteract is to promote the use of the subsoil. This article describes the technical procedure and development of an implement for stripe-wise subsoil melioration with application of compost in a layer of 30–60 cm. These stripes are each 30 cm wide and 70 cm apart. A technology has been developed for process, which allows the described procedure to be used over a large area. The melioration is carried out in one pass by an implement in an arrangement of 3 rows resulting in a working width of 3 m. A hopper on top of the implements frame includes an embedded hydraulic system to feed compost into the injection coulter. Results from 4-year field trials with standard crop rotations verify yield increases of up to 20% still 5 years after melioration. An overview of these trials and results will also be presented

Capability of the TrueColor Sensor Array for Determining the Nitrogen Supply in Winter Barley (Hordeum vulgare L.)

In agriculture, efforts are being made to reduce pesticides and fertilizers because of the possible negative environmental impacts, high costs, political requirements, and declining social acceptance. With precision farming, significant savings can be achieved by the site-specific application of fertilizers. In contrast to currently available single sensors and camera-based systems, arrays or line sensors provide a suitable spatial resolution without requiring complex signal processing and promise significant potential regarding price and precision. Such systems comprise a cost-effective and compact unit that can be extended to any working width by cascading into arrays. In this study, experiments were performed to evaluate the applicability of a TrueColor sensor array in monitoring the nitrogen supply of winter barley during its growth. This sensor is based on recording the reflectance values in various channels of the CIELab color space: luminosity, green–red, and blue–yellow. The unique selling point of this sensor is the detection of luminosity because only the CIELab color space provides this opportunity. Strong correlations were found between the different reflection channels and the nitrogen level (R² = 0.959), plant coverage (R² = 0.907), and fresh mass yield (R² = 0.866). The fast signal processing allows this sensor to meet stringent demands for the operating speed, spatial resolution, and price structure

Fruchtfolgen für optimierte Nutzung der Bodenressourcen: Mischanbau allorhizer und homorhizer Arten zur komplementären Durchwurzelung des Ober- und Unterbodens (Verbundvorhaben)

Das hier beschriebene Verbundvorhaben umfasst folgende Teilprojekte: FKZ 18OE024, FKZ 18OE045, FKZ 18OE046, FKZ 18OE047, FKZ 18OE048, FKZ 18OE142 Um Ertragslücken im ökologischen Ackerbau zu schließen, sollen durch die Ausbildung ausgedehnter Wurzelsysteme und die durch Pflanzenwurzeln verbesserte Bodenstruktur die Mobilisierung von Nährstoffen aus der Festphase des Bodens optimiert, sowie bisher nicht vollständig genutzte Wasser- reserven im Unterboden erschlossen werden. Dazu ist ein vertieftes Verständnis der Wurzel-Boden-Interaktion sowie des Wurzelwachstums im Gemenge im Vergleich zu Reinsaaten wichtig. Hier setzte das Forschungsprojekt MIKODU (Fruchtfolgen für optimierte Nutzung der Bodenressourcen: Mischanbau allorhizer und homorhizer Arten zur komplementären Durchwurzelung des Ober- und Unterbodens) an. Es beschäftige sich mit der Durchwurzelung von Futterpflanzen und Zwischenfrüchten und deren Wirkung auf Nachfrüchte, Bodenstruktur, Bodenwasserhaushalt, Stickstoffdynamik sowie Humusbildung. Dabei stand der Vergleich von Zwischenfrucht- und Futterpflanzen-Mischungen mit Reinsaaten im Fokus. In einem Feldversuch am Sand-Standort Hofgut Oberfeld in Darmstadt wurden zweijährig Mischungen und Reinsaaten allorhizer und homorhizer Futterpflanzen sowie eine Kontroll-Variante ohne Futter- pflanzen angebaut. Anschließend erfolgte der Anbau der Nachfrüchte Sommerweizen und Winterroggen. Am Auenlehm-Standort Wiesengut in Hennef an der Sieg wurden in zwei Jahren Feldversuche mit Zwischenfruchtreinsaaten und -mischungen angelegt. Die Mischungen wurden aus allorhiz und homorhiz wurzelnden Zwischenfruchtarten zusammengesetzt. Zur Bewertung der Vorfruchtwirkung wurde Sommerweizen angebaut. In einem dritten Versuch, ebenfalls am Wiesengut, wurde die meliorative Wirkung pfahlwurzelnder Kulturpflanzen in einem verdichteten Vorgewende untersucht. Dazu wurden verschiedene Varianten von Zwischenfrüchten und Futterpflanzen angebaut und anschließend der Ertrag und die Durchwurzelung der Nachfrüchte Sommerweizen und Winterroggen untersucht. Zur Erfassung der Wurzelmerkmale wurden die Profilwandmethode und die Monolithmethode angewendet. Die Bioporendichte wurde mittels Fotographie und digitaler Bildauswertung erfasst. Die Fourier-Transform-Infrarot Spektroskopie wurde zur Wurzelartentrennung der Mischungen genutzt. Messungen mit einem Penetrometer wurden zur Erhebung der Eindringwiderstände verwendet. Stechzylinder wurden für die Analyse der bodenphysikalischen Parameter entnommen. Darüber hinaus wurden Modellierungen mit SIMPLACE zur Quantifizierung der Stickstoff-Dynamik im Zwischenfruchtanbau, mit HYDRUS-1D zur Simulation des Bodenwasserhaushalts sowie mit HUMOD zur Quantifizierung der Humusbildung durchgeführt. Im Futterpflanzen-Versuch am Hofgut Oberfeld erreichten Luzerne und Luzerne-Rohrschwingel-Mischungen die höchsten Spross- und Wurzeltrockenmassen. Eine intensive Durchwurzelung des Unterbodens erreichte die Luzerne, eine intensive Durchwurzelung des Oberbodens die Gräser. Zudem zeigte Luzerne das höchste Potential zur Erhöhung der Bioporendichte. Im Zwischenfruchtversuch am Wiesengut zeigte das Screening mit der Profilwandmethode unterschiedliche Wurzeltypen. Mischungseffekte für Spross- und Wurzeltrockenmasse der Zwischenfruchtmischungen waren gering oder nicht vorhanden. Hingegen zeigten sich, insbesondere in Mischungen mit Ölrettich, hohe Mischungseffekte für die Durchwurzelungsintensität im Unterboden. Winterharte Zwischenfrüchte wiesen geringe Stickstoffverluste über Winter und niedrige C/N-Verhältnisse auf. Die Unterschiede in den Kornerträgen der Nachfrucht Sommerweizen waren gering, mit höchsten Erträgen nach legumen Zwischenfrüchten. Im Vorgewende-Versuch am Wiesengut zeigte der Anbau von pfahlwurzelnden Futterpflanzen, insbesondere von Wegwarte, ein höheres Bioporengenesepotential im verdichtenden Unterboden im Vergleich zu Zwischenfrüchten. Jedoch konnte bisher kein signifikanter Ertragsvorteil in den Getreide- Nachfrüchten nach diesen Pflanzen festgestellt werden. Die Wegwarte und die Wegwarte-Rohrschwingel-Mischung zeigten Tendenzen zur Bodenlockerung und Erhöhung der Luftkapazität. Die Modellierung ergab, dass Leguminosen und ihre Mischungen positiv zur Humusbilanz beitrugen, wobei der Humusaufbau durch Futterpflanzen höher war als durch Zwischenfrüchte. Insgesamt sind die Ergebnisse des gesamten Projektes ein wichtiger Schritt zu einem tieferen Verständnis von Dynamiken in Mischungen von Kulturpflanzen sowie der Wurzel-Boden-Interaktion