Fusion von Sensordaten zur Detektion von C- und N-Gehalten im Oberboden

Ziel: Die Studie untersucht die Kombination von Sensordaten (scheinbare elektrische Leitfähigkeit ECa gemessen mit EM38 und EM38-MK2 (1) sowie mit vis-NIR-Spektrometer (passives Spektrometer (bis 1700 nm) und Activ Flash Spectrometer (AFS, bis 1000 nm) des PhenoTrac4 (2) , beide mit Bildung verschiedener Indizes) zur flächigen Vorhersage von Corg, Ccarb, Ct und Nt auf einem Acker im ehemaligen Überflutungsgebiet der Isar (Mergel- im Wechsel mit sehr humosen Schichten über kalkhaltigem Schotter: Oberboden 9,36 % Ct, Ccarb: 5,96 %, Corg: 3.4, Nt: 0,41%). Methode: Schleppergestützte Messung der Fläche mit den genannten Sensoren. Beprobung von 45 Punkten mit anschließender Analyse der genannten Zielvariablen. Neben den Sensorwerten wurden auch die Gauß-Krüger-Koordinaten sowie die Entfernung der Probenahmepunkte zur Feldgrenze als Prädiktoren eingeführt. Auf die Verwendung von topographischen Parametern wurde verzichtet, da die rd. 2 ha große Fläche nahezu eben ist. Zur statistischen Vorhersage wurde Support Vector Machine Regressionen gerechnet. Ergebnis: Die Zielvariablen lassen sich mit Bestimmtheitsmaßen von 0,79-0,81 und RMSE-Beträgen von 0,01- 0,28 % abbilden. Dabei sind die bestimmenden Prädiktorvariablen bei Ct und Corg hauptsächlich die Nord-Süd-Ausdehnung, die Entfernung zur Feldgrenze, ECa-h sowie Reflexionswerte bei Wellenlängen um 1000 nm (AFS). Bei Ccarb und Nt treten die Nord-Süd-Ausdehnung zurück und Reflexionswerte von 400-600 kommen hinzu. Schlussfolgerung: Diese und andere unserer Studien haben folgendes aufgezeigt: - Die beschriebene Sensorkombination erhöht die Genauigkeit und auch die Reproduzierbarkeit der Messungen. - Die Einbeziehung von stetigen Variablen wie Koordinaten und auch topographischen Beschreibungen steigern die Komplexität und stabilisieren gleichzeitig die Berechnungen. - Während die ECa-Messungen weitestgehend standardisiert sind, fehlen derartige standardisierte Vorgehensweisen bei Reflexionsmessungen

High-throughput estimation of crop traits: A review of ground and aerial phenotyping platforms

Crop yields need to be improved in a sustainable manner to meet the expected worldwide increase in population over the coming decades as well as the effects of anticipated climate change. Recently, genomics-assisted breeding has become a popular approach to food security; in this regard, the crop breeding community must better link the relationships between the phenotype and the genotype. While high-throughput genotyping is feasible at a low cost, highthroughput crop phenotyping methods and data analytical capacities need to be improved. High-throughput phenotyping offers a powerful way to assess particular phenotypes in large-scale experiments, using high-tech sensors, advanced robotics, and imageprocessing systems to monitor and quantify plants in breeding nurseries and field experiments at multiple scales. In addition, new bioinformatics platforms are able to embrace large-scale, multidimensional phenotypic datasets. Through the combined analysis of phenotyping and genotyping data, environmental responses and gene functions can now be dissected at unprecedented resolution. This will aid in finding solutions to currently limited and incremental improvements in crop yields

Regional Patterns of Late Medieval and Early Modern European Building Activity Revealed by Felling Dates

Although variations in building activity are a useful indicator of societal well-being and demographic development, historical datasets for larger regions and longer periods are still rare. Here, we present 54,045 annually precise dendrochronological felling dates from historical construction timber from across most of Europe between 1250 and 1699 CE to infer variations in building activity. We use geostatistical techniques to compare spatiotemporal dynamics in past European building activity against independent demographic, economic, social and climatic data. We show that the felling dates capture major geographical patterns of demographic trends, especially in regions with dense data coverage. A particularly strong negative association is found between grain prices and the number of felling dates. In addition, a significant positive association is found between the number of felling dates and mining activity. These strong associations, with well-known macro-economic indicators from pre-industrial Europe, corroborate the use of felling dates as an independent source for exploring large-scale fluctuations of societal well-being and demographic development. Three prominent examples are the building boom in the Hanseatic League region of northeastern Germany during the 13th century, the onset of the Late Medieval Crisis in much of Europec. 1300, and the cessation of building activity in large parts of central Europe during armed conflicts such as the Thirty Years’ War (1618–1648 CE). Despite new insights gained from our European-wide felling date inventory, further studies are needed to investigate changes in construction activity of high versus low status buildings, and of urban versus rural buildings, and to compare those results with a variety of historical documentary sources and natural proxy archives.</jats:p

Quantification of mycorrhizal water uptake via high-resolution on-line water content sensors.

The benefits of mycorrhizas for host plants are well known for a large number of species. However, experimental evaluations of the hyphal contribution to the total water uptake and the assessment of the bulk flow velocity in the hyphae are so far contradictory. Barley (Hordeum vulgaris L. Scarlet) with the inoculum Glomus intraradices was grown in a split plant-hyphal chamber with a 5 mm air gap. During the preparation of the chambers with a loamy-silt soil, water content sensors were inserted in each of the plant and the hyphal compartments. These sensors allow non-destructive measurements with high resolution. In total, 8 drying periods with a length of several days were applied with repeated watering following each drying period. A clear decline in water content in the hyphal compartment during each drying period supports the ability of hyphae to transfer water into the plant compartment. The difference between the decline in the hyphal compartment with and without arbuscular mycorrhyzal fungi is significant at the p &lt; 0.000001 level. The direct and indirect hyphal contribution to the total water uptake was estimated to be about 20%. The application of capacitance sensors for water content determination with a special geometry adapted to the plant-hyphal chambers allows the evaluation of the hyphal water flow with high accuracy

Turnover of Chicken Manure in Some Upland Soils of Asia: Agricultural and Environmental Perspectives

The International Workshop on Chicken Manure Treatment and Application (CHIMATRA), Hamburg, Germany, 19-20 January 2005Recycling of organic manure/waste is an important global issue to improve soil productivity for sustaining agricultural production as well as to preserve the environment. In Asia, rearing of poultry especially chicken is becoming one of the key industrial sectors and the wastes from clean-out operations may contribute largely to plant nutrients. Thus, some recent research works on the use of chicken manure (CM) in the uplands of tropical Asia are reviewed. Relative loss of the added CM-C was averaged 83% during a 90-day incubation and in-situ retention of labile organic-C was poor in 2 years, signifying long-term episodes to sequestrate its inherent low C. Ammonification of the added CM was rapid during 1-2 weeks followed by oxidation of NH4+. The high pH of CM remarkably influenced nitrification either after a lag phase or immediately after application, ensuing NO3- leaching to occur under favourable conditions. Net mineralization/ nitrification was greater with CM than with other wider C/N ratio organic residues. CM-N recovery was relatively low, indicating immobilization and other N loss processes. Likewise, a large N2O loss of added CM-N with or without other N sources under field (0.99%) and laboratory (6.66%) conditions was observed, along with presumable NH3 volatilization. Composted CM/litter could reduce the loss by limiting the transformation of organic N. Application of CM (fresh/composted) either alone or with inorganic fertilizers demonstrated crop yield benefits and reduced the use of the latter as well as a noticeable residual effect to the succeeding crops. Results suggest that strategic but agro-economically viable composting might have great advantages in synchronizing CM-N release with plant uptake and in reducing appreciable amounts of labile C and gaseous N loss under upland conditions and thus, in minimizing environmental risk.Peer-review status unspecifie