About

Carl Rosen served as Head of the Department of Soil, Water, and Climate from 2011 to 2023. His research laboratory focuses on nutrient management for crop production, with an emphasis on identifying needs and establishing priorities in plant nutrition and improving fertilizer use efficiency in Minnesota. His primary research areas include contaminant hydrology and water quality, environmental chemistry, and nutrient management, particularly related to irrigated crops, fruit, and vegetable crops grown in Minnesota. His extension programs address water quality issues related to fertilizer use and the agricultural and horticultural use of municipal and industrial by-products as soil amendments. Rosen's work aims to optimize nutrient application, reduce environmental impacts such as nitrate leaching and nitrous oxide emissions, and improve crop yields and quality through sustainable nutrient management practices.

Research topics

• Biology
• Agronomy
• Chemistry
• Horticulture
• Environmental science
• Geography
• Machine Learning
• Computer Science
• Waste management
• Animal science
• Environmental engineering
• Soil science
• Remote sensing
• Mathematics
• Materials science
• Engineering
• Business
• Ecology

Selected publications

• Nitrogen and Sulphur Fertilization Effects on Maize Growth and Nutrient Uptake in Contrasting Soils

  Sarhad Journal of Agriculture · 2026-01-01

  articleOpen access
  PublisherDOI

• Postharvest Storage of Garlic (Allium sativum L.) Grown in Minnesota

  HortTechnology · 2026-01-02

  articleOpen accessSenior author

  Hardneck garlic varieties are the preferred types grown in cold climates, and they are typically planted in the fall, so that low winter temperatures promote bulb induction. Storage recommendations for garlic vary widely in the popular literature, and data-based storage recommendations are based on publications from the 1950s using softneck varieties. To learn how hardneck garlic shelf life is affected by storage temperature, on-farm and laboratory-controlled comparisons of ‘Chesnok Red’ and ‘Music’ bulb weight loss at 4 and 0 °C were done in studies conducted from 2022–24 and 2023–25. ‘Inchelium Red’, a softneck garlic, was also grown and stored in 2022–24 as a comparison with the hardneck types. In both years of the study, all garlic bulbs stored at 0 °C lost 5% to 7% of fresh weight, whereas bulbs stored at 4 °C or higher temperatures lost 35% to 40% fresh weight. Most bulbs stored at 4 °C, and none of those stored at 0 °C, started to sprout after 9 months in storage in 2023–24. In the following year of the study, only one ‘Music’ bulb stored at 4 °C sprouted. When transferred from 0 °C to room temperature after 9 months of storage from 2023–24, less than 10% of the ‘Music’ bulbs sprouted, whereas none of ‘Chesnok Red’ bulbs sprouted, even 2 months after transfer to room temperature. Fresh weight loss was greater after transfer to room temperature of bulbs stored previously at 4 °C than at 0 °C. Farmers who are selling hardneck garlic for consumption should store garlic at 0 to 4 °C. Farmers selling garlic for planting should store cured hardneck garlic at >4 °C, which can include room temperature (20 °C), as the time between curing and planting is usually about 3 months.

  PublisherDOI

• Organic amendments to potato soils inconsistently enrich yield-associated soil microbiota across growing regions of the continental US

  PeerJ · 2026-01-29

  articleOpen access

  Plant health is regulated by complex consortia of soil microbes with growth-promoting and pathogenic functions. In potato production, various soil management practices are undertaken to boost yields and suppress diseases, but connections between these practices, soil microbiomes, and tuber yields have not been characterized across diverse growing regions. To identify growing practices and microbes associated with increased yields, we established four-year field trials across eight US sites from Oregon to Maine that consisted of controls, fumigations, organic amendments, and mustard incorporations. Amplicon sequencing of 16S ribosomal RNA (rRNA) genes and intergenic transcribed spacer (ITS) regions was used to investigate bacterial and eukaryotic soil microbiomes, respectively. Fumigation and organic amendment treatments increased tuber yields in 23% and 29% of treatments relative to controls. While soil treatments influenced both microbiome types differently across all field sites, eukaryotes were more sensitive than bacteria to all treatments. Across field sites, soil treatments impacted relative abundances of amplicon sequence variants (ASVs) to varying degrees, even among ASVs belonging to the same genus. Associations between ASVs and tuber yields similarly varied within genera, highlighting the lack of consistent yield-associated taxa across US growing regions. Nevertheless, forty-five "target ASVs" across nine bacterial and three fungal phyla were identified as both treatment-impacted and yield-associated within any particular field site. Models identified three of thirteen organic amendment scenarios and one of thirteen fumigation scenarios where increased relative abundances of specific target ASVs accounted for up to a 23% increase in tuber yields compared to control treatments. These ASVs were largely site-specific and not influenced by treatment-associated changes in soil nutrients or organic matter, highlighting complex relationships within field sites that require further study to achieve the goal of implementing sustainable, microbiome-informed potato production techniques.

  PublisherDOI

• The economic performance of soil health practices in potato production systems – ADDENDUM

  Renewable Agriculture and Food Systems · 2025-01-01

  articleOpen access

  The authors would like to clarify that the USDA AMS potato prices used to calculate revenue and profit in their paper are in dollars per 50-lb units rather than dollars per hundredweight.Since the field trial yield data presented are in hundredweight, the prices used are effectively cut in half without explanation.However, dividing by two provides an approximation of grower returns.Potato cost and return studies typically scale shipping point prices to reflect returns to growers net of storage and packing costs paid to packing houses.(See https:

  PublisherOA PDFDOI

• Phosphorus management strategies for corn and soybean in the Upper US Midwest

  Agronomy Journal · 2025-03-01 · 2 citations

  articleOpen access

  Abstract It has been questioned whether the sufficient phosphorus (P)management approach could maximize potential grain yield in today's agricultural systems. The objective of this research was to establish six long‐term experiments across Minnesota to test phosphorus (P) management strategies on soils with a defined long‐term P history. Four soil test phosphorus (STP) interpretation classes were established as whole plots (low, medium, high, and very high). Split‐plots within each STP class consisted of one split‐plot that did not receive P (−P), and the second split‐plot received a broadcast application of P fertilizer (+P) at the rate of 73 (low), 44 (medium), 15 (high), and 15 (very high) kg P ha −1 . Grain yield, grain P concentration, and grain P removal were determined during corn ( Zea mays L.) (2015 and 2016) and soybean [ Glycine max (L) Merr.] (2017) growing seasons. Grain yield was increased by P fertilizer at 7 of 18 site‐years. Grain yields were similar between fertilized STP plots at the very low and low for corn and very low for soybean compared to nonfertilized or fertilized high and very high STP plots. No yield increase was noted for fertilized high or very high plots. Grain P removal was increased by applied P at 14 of 18 site‐years at the low and medium STP classes with no increase for the high and very high P testing soils. Results from this research indicate no greater yield potential for soils built to high or very high STP classes versus adequately fertilizing low‐ or medium‐testing soils.

  PublisherOA PDFDOI

• Phosphorus placement and microbial inoculation effects on potato yield and phosphorus recovery

  Agronomy Journal · 2025-05-01

  articleOpen accessSenior authorCorresponding

  Abstract Potatoes ( Solanum tuberosum L.) have been shown in previous studies to respond to P fertilizer on high‐P testing soils. Response to P under these conditions may be due in part to their shallow root systems and poor associations with mycorrhizal fungi due to the use of fumigation to control soilborne diseases. This study evaluated the effects of P placement and microbial inoculation on tuber yield and P recovery in high‐P soil. A field study with a split–split‐plot randomized complete block design was conducted over 2 years, with whole plots defined by fumigation treatment (no fumigant or metam sodium) and subplots defined by cultivar (Ivory Russet or Russet Burbank). Each subplot was divided into seven sub‐subplots by P treatment. Four treatments were used to evaluate banded versus broadcast P placement at 37 and 73 kg P ha −1 without inoculant. Four treatments were used to evaluate the effect of broadcast P at 0 and 73 kg P ha −1 with or without an inoculant. At equivalent P rates, banded P placement produced 4.8% greater tuber yield, 4.8% greater P uptake, and 5.0% greater P recovery efficiency (PRE) than broadcast placement. However, microbial inoculation had no effect on tuber yield, P uptake, or PRE with or without fumigation. High soil P or control of foliar fungi may have inhibited mycorrhizae. Overall, at equivalent P rates, banded P placement increased tuber yield even under high soil P conditions, but inoculation with arbuscular mycorrhizal fungi and other beneficial microbes had no effect.

  PublisherOA PDFDOI

• Compost amendments to potato soils enrich yield-associated members of soil microbiomes across the continental US

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-02-26 · 2 citations

  preprintOpen access

  Abstract Plant health is regulated by complex consortia of soil microbes with growth-promoting and pathogenic functions. In potato production, various soil management practices are undertaken to boost yields and suppress diseases, but connections between these practices, soil microbiomes, and tuber yields have not been characterized across diverse growing regions. To identify growing practices and microbes associated with increased yields, we established four-year field trials across eight US sites from Oregon to Maine that consisted of controls, fumigations, organic amendments, and mustard incorporations. Soil microbiomes consisted of 16S and ITS amplicon sequences from bacteria and microeukaryotes, respectively. While soil treatments influenced microbiomes differently across all field sites, eukaryotes were more sensitive than bacteria to all treatments. Soil treatments impacted proportions of distinct amplicon sequence variants (ASVs), and associations between ASVs and tuber yields varied within genus-level taxonomy and across field sites. Forty-five ASVs were identified as both treatment-impacted and yield-associated within any field site. Models identified three of thirteen compost amendment scenarios and one of thirteen fumigation scenarios that increased tuber yields by increasing proportions of these taxa within soil microbiomes. These ASVs were not influenced by treatment-associated changes in soil nutrients or organic matter, highlighting complex relationships within specific field sites that require further study to achieve the goal of implementing sustainable, microbiome-informed potato production techniques. Importance Soil microbes play diverse and interconnected roles in mediating plant health, growth, and disease, but understanding the specifics of how they work and applying them across different agricultural systems remains a challenge. To address this, we amassed a dataset from eight potato field sites across major US growing regions consisting of nearly two thousand soil bacterial and fungal microbiomes paired with soil chemical and tuber yield data. We describe how soil microbiomes are impacted by different soil treatments (compost amendments, chemical fumigation, and mustard incorporation), and identify treatments that boosted yields by up to 23% by increasing proportions of certain bacterial or fungal sequences. Compost amendments affected yield-associated taxa more often than other soil treatments, but these effects varied by rotation length and growing region. Changes to soil chemistry resulting from specific soil treatments did not influence abundances of yield-associated taxa, suggesting that the ways in which they may act to maintain plant vigor are field-specific and complex, calling for further study.

  PublisherOA PDFDOI

• Evaluating the Potential of Improving In-Season Potato Nitrogen Status Diagnosis using Leaf Fluorescence Sensor as Compared with the SPAD Meter

  Preprints.org · 2025-05-20 · 1 citations

  preprintOpen accessSenior author

  In-season nitrogen (N) status diagnosis is an effective way to guide split N applications for improved profitability and minimized negative environmental impacts. Petiole nitrate-N concentration (PNNC) has been an industry standard indicator for in-season potato (Solanum tuberosum L.) N status diagnosis but is limited because of destructive sampling and chemical processing needs. Leaf sensors can be used to predict PNNC and other N status indicators and overcome these challenges. The SPAD meter is a sensor commonly used to estimate leaf chlorophyll (Chl) based on transmittance, while Dualex is a newer leaf sensor that can also measure leaf flavanol (Flav) and anthocyanin (Anth) through Chl fluorescence. Limited research has been conducted to compare the two leaf sensors for potato N status assessment, despite their respective success in N status diagnosis for other crops. Therefore, the objectives of this study were to 1) compare the performance of the Dualex sensor relative to the SPAD meter for predicting potato N status indicators when only sensor data are used, 2) evaluate the potential of improving potato N status prediction using multi-source data fusion compared with only using leaf sensor data, and 3) develop practical strategies for leaf-sensor-based in-season potato N status diagnosis. The plot-scale experiments were conducted in Becker, Minnesota, USA in 2018, 2019, 2021, and 2023 involving different cultivars, N treatments, and irrigation treatments in a split plot design with three replications. Leaf sensor data and plant samples were simultaneously collected and processed multiple times at key growth stages each year. Daily weather data were also collected at the on-site weather station. Different in-season potato N status indicators including PNNC and N nutrition index (NNI) were derived from plant samples, while weather- and management-related parameters were calculated using the weather data and management records. Dualex’s N balance index (NBI; Chl/Flav) always outperformed Dualex Chl but did not consistently perform better than the SPAD meter. All N status indicators were predicted with significantly higher accuracy with multi-source data fusion using machine learning models. A practical in-season potato N status diagnostic strategy was developed using linear support vector regression model with SPAD, cultivar information, accumulated growing degree days (GDDs), accumulated total moisture, and as-applied N rate to predict vine or whole plant NNI, achieving an R² of 0.80 - 0.82, accuracy of 0.75 - 0.77, and a Kappa statistic of 0.57 - 0.58 (near-substantial). Further research is also required to determine the critical N dilution curve and sufficiency ranges of NNI for potatoes based on different genetic, environmental, and management conditions to better support decision-making.

  PublisherOA PDFDOI

• Precipitation influences pre‐sidedress soil nitrate thresholds for corn production

  Soil Science Society of America Journal · 2025-05-01

  articleOpen access

  Abstract Minnesota is a leading corn ( Zea mays L.) producer in the United States, requiring substantial nitrogen (N) inputs for optimal yields. Using an in‐season critical soil nitrate (NO 3 − ‐N) concentration threshold to adjust fertilization rates can improve N management and reduce environmental impacts. This study assessed corn grain yield response to in‐season (i.e., V4–V6 corn development stage) soil NO 3 − ‐N concentration to establish a critical pre‐sidedress soil NO 3 − ‐N test (PSNT) under Minnesota conditions. Data included were obtained from 34 field experiments conducted from 2012 to 2019 across the major corn production regions of Minnesota. Relationships between PSNT and relative corn grain yield were analyzed using a quadratic‐plateau regression model. Across the entire dataset, a PSNT of 20 ± 2.5 mg NO 3 − ‐N kg −1 soil was the critical level to reach 97% of maximum corn grain yield. To increase suboptimum PSNT concentrations up to the critical threshold, application of 13.8 ± 2.4 kg N ha −1 is needed per 1 mg kg −1 increase in soil NO 3 − ‐N concentration based on pre‐/at planting N application, but validation is needed for actual sidedress applications. When precipitation was lower or greater than the 30‐year mean, the critical PSNT value was 21.5 or 17.4 mg kg⁻¹, respectively. Nonetheless, the 20 ± 2.5 mg NO 3 − ‐N kg −1 PSNT critical value is applicable across the state as limited model improvements were achieved when the data were segregated according to soil characteristics, location, corn material, and/or previous crop.

  PublisherOA PDFDOI

• Evaluating the Potential of Improving In-Season Potato Nitrogen Status Diagnosis Using Leaf Fluorescence Sensor as Compared with SPAD Meter

  Remote Sensing · 2025-07-05 · 4 citations

  articleOpen accessSenior author

  The petiole nitrate–nitrogen concentration (PNNC) has been an industry standard indicator for in-season potato (Solanum tuberosum L.) nitrogen (N) status diagnosis. Leaf sensors can be used to predict the PNNC and other N status indicators non-destructively. The SPAD meter is a common leaf chlorophyll (Chl) meter, while the Dualex is a newer leaf fluorescence sensor. Limited research has been conducted to compare the two leaf sensors for potato N status assessment. Therefore, the objectives of this study were to (1) compare SPAD and Dualex for predicting potato N status indicators, and (2) evaluate the potential prediction improvement using multi-source data fusion. The plot-scale experiments were conducted in Becker, Minnesota, USA, in 2018, 2019, 2021, and 2023, involving different cultivars, N treatments, and irrigation rates. The results indicated that Dualex’s N balance index (NBI; Chl/Flav) always outperformed Dualex Chl but did not consistently perform better than the SPAD meter. All N status indicators were predicted with significantly higher accuracy with multi-source data fusion using machine learning models. A practical strategy was developed using a linear support vector regression model with SPAD, cultivar information, accumulated growing degree days, accumulated total moisture, and an as-applied N rate to predict the vine or whole-plant N nutrition index (NNI), achieving an R2 of 0.80–0.82, accuracy of 0.75–0.77, and Kappa statistic of 0.57–0.58 (near-substantial). Further research is needed to develop an easy-to-use application and corresponding in-season N recommendation strategy to facilitate practical on-farm applications.

  PublisherOA PDFDOI

Frequent coauthors

• Michael J. Sadowsky

  23 shared

• Peter M. Bierman

  University of Minnesota

  18 shared

• John F. Moncrief

  18 shared

• Satish C. Gupta

  17 shared

• Rodney T. Venterea

  16 shared

• Michael P. Russelle

  University of Minnesota

  15 shared

• Gary W. Feyereisen

  15 shared

• James J. Luby

  University of Minnesota

  14 shared

Labs

• Soil, Water, and ClimatePI

Education

• Ph. D. , Land, Air and Water Resources; Soil Science

  University of California, Davis

  1983

• Master of Science, Horticulture

  Pennsylvania State University

  1978