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Abstract Soil health can differ across cropping systems because of variation in edaphic and management factors. We evaluated how biological indicators of soil health (soil organic matter [SOM], permanganate oxidizable carbon [POXC], mineralizable carbon [MinC], autoclaved‐citrate‐extractable [ACE] protein, and potentially mineralizable nitrogen [PMN]) compared across four common Wisconsin cropping systems: grazed cool‐season pastures, forage‐based rotations that included perennial legumes or grasses, annual rotations receiving manure, and annual rotations receiving synthetic fertilizers. Biological indicators of soil health were up to 195% greater in pastures than other cropping systems. MinC, POXC and PMN were 10%–90% greater in forage‐based rotations than annual cropping systems, but only MinC and POXC were greater in annual systems with manure compared to those without manure by 35% and 7%, respectively. Perennial vegetation and livestock integration offer the greatest potential to increase biological indicators of soil health in agricultural lands.

Abstract The accumulation of soil organic matter (SOM) is vital to the agronomic and environmental functioning of agroecosystems, yet the relative influence of inherent soil properties and agricultural management practices on SOM dynamics are not often addressed in individual studies. Using a network of 218 operating farm fields across Wisconsin and southern Minnesota, USA, this research employs single variable analysis (ANOVA and regression) and regression tree analysis to assess the effects of soil properties (texture, drainage class, and pH) and management variables related to crop rotation, tillage, cover cropping, and manure application on SOM, as well as total organic carbon (TOC) and total nitrogen (TN) in the upper 15 cm. Single variable analysis revealed that greater SOM, TOC, and TN were associated with poorly drained soil, tile‐drained fields, high clay content soil, and high biomass crop rotations. SOM and TOC were strongly related (R2 = 0.71), but different regression trees were produced; SOM was most influenced by clay content, while TOC was most influenced by drainage class. Future assessment for the building of SOM or TOC should be conducted with drainage and texture class categories and on a regional basis, given that these factors influence the practices that occur within landscapes. A rapid building of datasets through unstructured sampling, including an abundance of metadata, should be a research priority in agricultural science to identify practices to build SOM on a regional basis.

For higher-efficiency solar cell structures, such as the Passivated Emitter Rear Contact (PERC) cells, to be fabricated in a manufacturing environment, potentially low-cost techniques such as inkjet printing and metal plating are desirable. A common problem that is experienced when fabricating PERC cells is low fill factors due to high series resistance. This paper identifies and attempts to quantify sources of series resistance in inkjet-patterned PERC cells that employ electroless or light-induced nickel-plating techniques followed by copper light-induced plating. Photoluminescence imaging is used to determine locations of series resistance losses in these inkjet-patterned and plated PERC cells.

The amount of soil organic matter (SOM) is considered a key indicator of soil properties associated with higher fertility. Despite the ubiquity of assumptions surrounding SOM's contributions to soil functioning, we lack quantitative relationships between SOM and yield outcomes on working farms. We quantified the relationship between SOM and yields of corn (Zea mays L.) and silage for a dataset of 170 fields arrayed across 49 farms in a network of growers based in Wisconsin and Minnesota, USA. As SOM concentrations increase so do yields, though gains start to level off around 4% SOM. When examining the relationship between yield and soil health indicators representative of biologically active C pools, we found that mineralizable C has a stronger relationship with yield than permanganate oxidizable C. Mineral fertilizer, manure, and SOM had relationships of similar magnitude with yield, highlighting that SOM in combination with exogenous inputs likely plays an important role in driving agricultural productivity in this region. An interaction between SOM and crop rotation indicated that the impact of SOM on crop yields varied depending on rotation (continuous corn vs. corn in rotation). That is, continuous corn had lower yields than corn in rotation despite higher SOM concentrations. Our findings provide insight into the relationship between indicators of soil health, farm management, and crop yields for a set of working farms and lend support to the goals of soil health initiatives that rest on building SOM in agricultural soils to improve agricultural outcomes. Core Ideas: Higher SOM is associated with greater yields of corn and silage.Crop yields start to level off at around 4% SOM.The yield–SOM relationship varied depending on crop rotation.Min‐C maps closely with the relationship between SOM and yield. [ABSTRACT FROM AUTHOR]

Thin-film Cu(In,Ga)Se2 modules are investigated by electro-modulated luminescence with bias illumination. The large signal analysis enables the determination of the average current density/voltage (J/V) characteristics of individual cell-stripes in a module, without contacting each individual cell. It was found that the characteristics determined from electro-modulated photo-luminescence measurements differ from the characteristics determined without bias illumination via electro-luminescence. As a reason for this, we found the non-linear relation of the local current to the local voltage which makes the determination of the cell voltage via an average of the local voltages determined from electro-luminescence images incorrect especially at high injection currents. A second analysis method using the small signal response of electro-modulated photo-luminescence was also analyzed. Recently, a method based on such a small signal analysis was demonstrated that yields the local photocurrent collection efficiency. This contribution presents the first application of this method to solar modules with series connected cells rather than the previously shown analysis of single cells. We compare two ways to evaluate the photocurrent collection efficiency from the small signal analysis and discuss how applicable these measurements are to modules. We find that the photocurrent collection efficiency of modules gives valuable information about how defective cells act within a module and which parts of the module limit the overall current through the module. [ABSTRACT FROM AUTHOR]

Photoluminescence imaging has widely been used as a characterisation tool for the development of silicon solar cells. However, photoluminescence images typically only give qualitative information due to the presence of an unknown calibration constant. In this work, quasi-steady-state photoconductance measurements on partially processed solar cells and I-V measurements on finished solar cells are used to determine the calibration constants to yield spatially resolved implied open circuit voltage images. This technique is then applied to determine the implied open circuit voltage of laser doped selective emitter solar cells at various stages of cell fabrication after the formation of the full area aluminium back surface field when other characterisation techniques such as photoconductance cannot be used. [ABSTRACT FROM AUTHOR]