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Potato production requires intensive nitrogen (N) fertilization. To maintain yield and profitability, potato farmers must satisfy the need of the crops for N by applying fertilizer during the growing season. Petiole nitrate analysis and whole leaf total N test have been studied before to guide in-season N application, and both have strengths and weaknesses. Whole vine total N test has been discussed by the US potato industry as another diagnostic tool to understand the overall N uptake of the plant, but little data are available. A 2-year field study was conducted at the University of Wisconsin Hancock Agricultural Research Station in 2018 and 2019 with the objective to compare three diagnostic tools, petiole nitrate analysis, whole leaf total N test and whole vine total N test, for identifying the nutrient status of two chipping potato cultivars subjected to five different N rates. It was found that petiole nitrate analysis is still the most responsive method to reflect supplemental N application during the growing season and is the most relevant to final tuber yield. Whole leaf total N test is less responsive, but it can reflect plant N uptake up to the date of testing. Comparatively, whole vine total N test is not acceptable because of the excessive amount of time needed to collect and process the samples, and the concern over whether or not the sample tested in the last step of analysis is representative. Future diagnostic tools using cutting-edge remote sensing and machine learning technologies that can detect spatial variability should be developed to further enhance the effectiveness of in-season N monitoring, which is critical for sustainable potato production.

Pellets from fen paludicultures (Typha ssp. and Phalaris arundinacea) were produced, analysed and combusted in a 15 kW pellet boiler at TFZ. Fuels comprised both of pure and kaolin additivated pellets as well as of paludiculture-wood-pellet blendings. Standard ENplus wood pellets (A1 quality) were used as a reference fuel. Gaseous and total particulate matter (TPM) emissions as well as slagging tendencies were measured. Typha ssp. showed high CO and particle emissions while Phalaris arundinacea showed an increased risk of slag formation. Additivation with kaolin did neither improve emission behaviour nor slagging tendencies at the applied additivation levels following the guidelines of the ERA-NET project "BIOFLEX!". Blending with wood pellets strongly reduced NOX, SOX and HCl emissions. Overall, combustion of fen paludicultures in small-scale boilers remains challenging and requires a dedicated boiler technology., Proceedings of the 30th European Biomass Conference and Exhibition, 9-12 May 2022, Online, pp. 653-656

Listening, the most efficient means of learning in the early grades, is replaced by reading as an efficient method for learning after the seventh grade. For an investigation of the effectiveness with which college students may be taught listening, lesson plans were developed from a programed instruction book --Principles of Selective Listening-- that was written in 1968 under the direction of John W. Blythe. A sample of 132 students at East Texas University was drawn from students who were enrolled in a Personality Foundations course. Each student was given a hearing test to determine his ability to hear, the Otis Quick-Scoring Mental Ability Tests, Form Fm to ascertain his intelligence quotient, and the Brown-Carlsen Listening Comprehension Test, Form Am as a pre- and post-test. Pre-test and mental ability scores made it possible to equate groups of students. From the total sample, 2 classes were designated as control, and 2 as experimental groups, and the 4 classes met 3 days a week for 1 hour and 20 minutes. It was concluded that listening ability can be measured objectively, but that a person's ability to listen cannot be increased regardless of his mental ability. The null hypothesis --that there was no significant difference between students who were taught effective listening habits and those who were not-- was accepted. The report contains recommendations for future research on the value of the teaching of listening. (WM)

Fuel quality and combustion behaviour of agricultural pellets from paludiculture straw were tested within the research project “MOORuse”. Pellets were produced from Typha ssp., Phragmites australis, Phalaris arundinacea and Carex ssp..Additivation of pellets with kaolin was applied to reduce particle emissions and slagging. Physical fuel properties of pellets met the requirements of ISO 17225-6. Chemical fuel properties(e.g.K and Na content) indicated high TPM emissions for Typha ssp. Distinct slagging for the other species were predicted (e.g. by Si/K-index). During combustion in a small-scale biomass boiler (30 kW), CO and TPM emissions were high for Typha ssp. (CO: 292 mg/m3, TPM: 115 mg/m3, STC) but were reduced by additivation with 2.3 w-% kaolin (CO: 143 mg/m3, TPM: 94 mg/m3, STC). Slagging was high for Phragmites australis, Phalaris arundinacea and Carex ssp. with >40 w-% of total ash consisting of particles >8 mm. Additivation had no positive effect on slagging. In conclusion, paludiculture pellets are challenging fuels that require sufficient fuel upgrading, e. g. by additivation or fuel blending, and a suitable boiler technique that fulfils the legal requirements for the combustion of agricultural fuels in Germany. These requirements are easier met by medium sized combustions plants >100 kW., Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 399-407

Wood pellets typically consist of sprucebut also other wood species are added during pellet production. Moreover, additives such as binders and kaolin are added in small ratios to improve fuel quality and combustion behavior.In this study eight different wood species were used for pellet production as well as three binders and one type of kaolin were added to sprucewood without bark, using two additivation levels. All wood pellet assortments were extensively analyzed regarding their physical and chemical properties and combusted in a 6 kW pellet stove and a 15 kW pellet boiler. The results confirmed a significant impact of the wood species on emissions for the pellet stove ranging between 85 (douglas fir) and 4,189 mg/Nm³ (apple wood) for CO and 23 (pine wood) and 263 mg/Nm³ (apple wood)for total particulate matter(TPM)-emission. Similar combustion behaviour was observed for the pellet boiler test but at a lower emission level. For wood species with a high molar Si/K-ratio,lower emissions but also serious slagging was observed. Binders may affect emissions when high additivation levels are used depending on the kind of binder. Kaolin reduced CO and TPMemissions as well as slag formation, when the additivation level was according to appropriate stoichiometric calculations. When kaolin is overdosed it may have negative impact on TPM emissions due to entrainment or problems caused by the higher ash content. Additionally, slagging is increased by high additivation levels of kaolin. Generally,at the current state of the art the pellet stove technology shows larger susceptibility towards variable pellet qualities compared to automatic pellet boilers., Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 389-398

Careful operation during fuel production is essential to avoid highshares of mineral soil inwood chips leading to contamination of the biofuels. This can result in elevated gaseous and particulate emissions, corrosion or slag formation during combustion in the biomass boiler. To investigate this effect, stemwood and forest residue wood chip fuels were contaminated with mineral soil at two different ratios. Contamination was done using three typical forest soils from Bavaria (soil A, B and C). Total particulate matter (TPM) emissions increased for wood chips that when contaminated with soil A and C, compared to the reference fuel, but emissions for wood chips contaminated with soil B remained constant. Carbon monoxide (CO) and organic gaseous carbon (OGC) emissions decreased for contaminated wood chips. For NOX emissions, no clear effect was observed. Overall, the contamination of woody biomass had a noticeable effect on pollutant emissions and should be avoided., Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 662-667

Potato is the largest non-cereal food crop in the world. Timely estimation of end-of-season tuber production using in-season information can inform sustainable agricultural management decisions that increase productivity while reducing impacts on the environment. Recently, unmanned aerial vehicles (UAVs) have become increasingly popular in precision agriculture due to their flexibility in data acquisition and improved spatial and spectral resolutions. In addition, compared with natural color and multispectral imagery, hyperspectral data can provide higher spectral fidelity which is important for modelling crop traits. In this study, we conducted end-of-season potato tuber yield and tuber set predictions using in-season UAV-based hyperspectral images and machine learning. Specifically, six mainstream machine learning models, i.e., ordinary least square (OLS), ridge regression, partial least square regression (PLSR), support vector regression (SVR), random forest (RF), and adaptive boosting (AdaBoost), were developed and compared across potato research plots with different irrigation rates at the University of Wisconsin Hancock Agricultural Research Station. Our results showed that the tuber set could be better predicted than the tuber yield, and using the multi-temporal hyperspectral data improved the model performance. Ridge achieved the best performance for predicting tuber yield (R2 = 0.63) while Ridge and PLSR had similar performance for predicting tuber set (R2 = 0.69). Our study demonstrated that hyperspectral imagery and machine learning have good potential to help potato growers efficiently manage their irrigation practices.

A critical step in profitable post-harvest potato storage management is to cure tubers at appropriate temperatures long enough for rapid wound-healing to prevent disease and defect development, but not too long to jeopardize storage quality. A two-year storage study was conducted in macro-storage totes at the University of Wisconsin Hancock storage research facility to evaluate the effects of higher wound-healing temperatures (15.6 &deg, C, 18.3 &deg, C) imposed for different durations, and compare them to the U.S. potato industry&rsquo, s standard practice (12.8 &deg, C), on weight loss and frying quality of multiple processing potato varieties during long-term storage. It was found that in the experimental setting of this study, warmer wound-healing temperatures resulted in (1) less weight loss, particularly during the early storage season across varieties, (2) ameliorated senescent sweetening of the Snowden variety, (3) improved fry quality of the Russet Burbank variety, (4) and no apparent disease spread during long-term storage if tubers were harvested healthy out of fields. Overall, no significant difference was found between 15.6 &deg, C and 18.3 &deg, C regarding their treatment effects. Our conclusion is that compared to the current standard practice, higher wound-healing temperatures may have the potential benefits of improving potato storage quality while reducing the economic penalty associated with weight loss for specific varieties, but tubers should be healthy at harvest in order to gain the benefits. Further research is needed to test if those benefits of higher wound-healing temperatures hold true in large-scale commercial storage facilities.

Uncertainty exists regarding the depth and extent to which agricultural practices affect soil properties, in particular soil organic C (SOC). In this study we examined the impact of 53 yr of continuous corn (Zea mays L.) receiving varying rates of inorganic N fertilizer with complete stover return on soil properties including SOC, total N, and bulk density (BD) to a depth of 1 m. In the treatment receiving virtually no applied N there was a significant reduction in soil N content at 0 to 30 cm over the study period, while the treatment receiving N in excess of recommended application levels was similar to the treatment receiving recommended rates of N fertilizer. Trends in SOC content were similar to those for total N, but a significant treatment effect was detectable throughout the entire 1-m soil profile sampled. Over the course of the study, all experimental fields appeared to have lost approximately 6 cm of topsoil through erosion, with the lowest N rate plots subsiding a further 2 cm due to compaction. Despite using disruptive management practices (moldboard plowing and application of anhydrous ammonia), declines in soil C and N content were not apparent for this soil type under conditions of low slope and the linear gains in productivity realized under the two higher N rate treatments. Thus N fertilizer was a benefit to this cropping system, rather than a detriment, and was sufficient to allow maintenance—but not building—of SOC.

Firewood stoves may cause high particulate matter (PM) and gaseous emissions, and user behaviour is an important influence, although to date only rarely quantified. Therefore, a manually operated modern firewood stove (7 kW) was selected and tested on a combustion test stand in a comprehensive experimental plan where in total 5 stove ignition variants (cold starts at natural draught) and 9 stove operational variants were investigated, each in 3 replications. Ignition variants differed in the position of starter blocks igniters as well in the orientation and position of wood logs and kindling used, including the “top down” and “bottom up” ignition modes, which both were additionally tested in a setup with controlled chimney draught at -12 Pa. Operational variants comprised a refilling according to the stove user manual (a), different primary air settings (b), overload of fuel (c), different moisture contents between 7 and 30 w-% (d), too long logs (e), delayed recharging (f) a "quasi-continuous" charging of individual logs (g). The ignition from the bottom caused lower CO-, OGC, and PM-emissions compared to the ignition from the top, but highest concentrations were observed when using crumped newspaper as igniter from the bottom in an "inaccurate" fuel arrangement. In subsequent batches the firewood stove performed very well when operated according to the user manual (CO: 1,687 mg/m3; OGC: 212 mg/m3; PM: 22 mg/m3, related to 13 % O2-conc.). Highest emissions were released when the primary air flap remained open after the ignition batch (CO: 9,379 mg/m3; OGC: 1,283 mg/m3; PM: 142 mg/m3). Such maloperation would be avoided if the stove was equipped with a relatively simple automatic combustion air control. High emissions also occurred when the stove was recharged after the flames were already extinguished or when the fuel was too wet. By throttling the combustion air flow, the CO emissions were increased by the factor 1.7 compared to the proper stove operation. Similarly, an overfilling of the combustion chamber also led to increased gaseous emissions. The use of too long wood logs, too dry wood or the continuous refilling with single logs led to similar or slightly lower gaseous and particulate matter emissions compared an orderly stove operation as defined as reference case., Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 409-418

Due to careless operation during fuel production, considerable shares of mineral soil might be added to wood chips and wood pellets leading to contamination of the biofuels. This can result in high gaseous and particle emissions, corrosion or slag formation during combustion. To investigate this effect, four pellet fuels were produced at TFZ using coniferous wood of Norwegian spruce, i. e. a pure sample as reference and three pellets that were contaminated with different mineral soils (2 w-%). The contaminated pellets had significantly higher ash contents (2.47 to 2.63 w-%, d.b.) compared to the reference fuel (0.83 w-%, d.b.). The reference sample fulfilled the specifications for A2 according to DIN EN ISO 17225-2, while the contaminated pellets only met the I3 quality criteria. A visual differentiation between contaminated and uncontaminated fuels was not possible. The pellets were combusted in a pellet boiler with a nominal heat output of 15 kW. During combustion of the contaminated pellets, the boiler shut down because of to severe slag and ash formation after 118, 120 and 278 minutes of full load operation. Particle emissions and NOX decreased for the soil contaminated pellets compared to the reference fuel while SOX increased. Carbon monoxide was on a very low level for all fuel assortments. A final interpretation of the correlation between soil contamination of wood pellets and their respective emission behaviour is not possible yet as analysis of chemical element concentration is still ongoing. Overall, the contamination of woody biomass had a noticeable effect on emissions and on the continuous, undisturbed operation of the pellet boiler and should be avoided., Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 673-680

The use of wood pellets is steadily increasing in the European Union. The majority of wood pellets on the German market carry the label ENplus indicating a consistent fuel quality. In order to prove this assumption 42 different pellet samples in bags were collected and extensively analyzed. This included combustion properties, physical properties as well as their chemical composition. Eight of the 42 samples did not fulfil the requirements for the standard DIN EN ISO 17225-2. But overall a positive result for wood pellets quality on the German and European market was confirmed. Interestingly, large differences in potassium content (between 280 and 900 mg/kg) which can influence the amount of particle emission were observed. During the combustion of 12 selected pellet samples, no clear dependency between flue gas emission and ash content, potassium content, bulk density or pellet length were found. Therefore, the selection of the fuel can lead to big uncertainties during the combustion in pellet stoves. This has to be further investigated in order to maybe fine the yet unknown pellet parameter influencing the emission behavior in a pellet stove., Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 667-672

Anaerobic storage of wood chips from forest residues and from short rotation coppice was investigated regarding dry matter losses and fuel quality changes using three approaches, i.e. small storage container (including greenhouse gas (GHG) measurements), small-scale silos of 2 m3 volume and a small wood chip pile (12 m3). After storage, selected wood chip samples were combusted in a 30 kW wood chip boiler and relevant emissions (CO, NOX, particles) were measured. Container trials allowed for best anaerobic conditions reducing dry matter losses to a minimum of 2 w-% after 5 months of storage. Silos proved not to be completely air tight as moisture content increased by 4.2 to 10.4 w-% due to precipitation and distinct dry matter losses were recorded. Still, dry matter losses were lower in silo trials compared to storage in a pile. During combustion, CO and particle emissions increased in naturally stored materials compared to technically dried fuels, probably due to changes in their woody structure but also due to an increase in chemical elements such as potassium. In conclusion, anaerobic storage seems to be an interesting option to reduce dry matter losses. Future studies should focus on the applicability of this technique under practical conditions (e.g. in large driving silos) and on further combustion trials., Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 630-636

Imaging spectroscopy provides the opportunity to monitor nutrient status of vegetation. In crops, prior studies have generally been limited in scope, either to a small wavelength range (e.g., 400–1300 nm), a small number of crop cultivars, a single growth stage or single growing season. Methods that are not time- or site-specific are needed to use imaging spectroscopy for routine monitoring of crop status. Using data from four cultivars of potatoes (Solanum tuberosum L.), three growth stages and two growing seasons, we demonstrate the capacity of full-range (400–2350 nm) imaging spectroscopy to quantify nutrient status (petiole nitrate, whole leaf and vine total nitrogen) and predict tuber yield in potatoes across cultivars, growth stages and growing seasons. We specifically tested the capabilities of: (1) ordinary least-squares regression (OLSR) using traditional hyperspectral vegetation indices (VIs); (2) partial least-squares regression (PLSR) using full spectrum (400–2350 nm), VNIR- (visible-to-near infrared: 400–1300 nm) or SWIR-only (shortwave infrared: 1400–2350 nm) wavelengths; (3) predictive models developed for one potato type or planting season on withheld data from a different type or season. Our results show that OLSR models produced poor predictions with data from all dates pooled together (validation R2