About

Robert Meinen is the Director of the Pennsylvania Nutrient Management Education Program and a State Extension Specialist in Nutrient & Manure Management. He holds a Soil Science PhD, an Animal Science MS, and an Agricultural Systems Management BS. These degrees are from different disciplines and departments within the Penn State College of Agriculture, and he currently resides in the Department of Plant Sciences. Robb strives to simultaneously advance agricultural production and the environment. His expertise includes nutrient and manure management, manure hauler certification, agricultural air quality, agricultural odors, the swine industry, and pork quality assurance. He has spearheaded educational efforts for the Pennsylvania Commercial Manure Hauler and Broker Certification program. His work focuses on managing soil nutrients amid fertilizer price volatility, environmental safety considerations in manure application, manure gas safety, and importing manure practices. Robb's contributions aim to improve agricultural practices while protecting environmental quality.

Research topics

• Ecology
• Agronomy
• Biology
• Environmental science
• Business
• Agricultural science
• Economics
• Environmental resource management
• Agroforestry
• Natural resource economics
• Marketing
• Geography
• Agricultural economics
• Environmental planning

Selected publications

• Spatiotemporal trends and driving forces of pig production in China and the United States

  Earth Critical Zone · 2025-01-01 · 1 citations

  articleOpen access

  Pig production plays a crucial role in meeting global nutritional needs, but its uneven spatial distribution results in localized increases in a series of nitrogen related pollution risks to water and air quality issues. This study examines the factors influencing the spatial distribution of pig production in China and the United States, the two largest pig producers globally, using provincial and county-level data from 2000 to 2021. Our findings reveal distinct patterns in both countries. In China, between 1990 and 2017, high pig production density areas shifted from the southern regions to the north, aligning with population and economic distribution but showing no significant relationship with feed supply. Conversely, in the United States, high pig production density areas expanded near the ‘Corn Belt,’ corresponding closely with feed supply distribution, with less influence from population or economic factors. In China, the spatial distribution of pig production is positively correlated with market demand and transportation infrastructures, but not with feed supply. In the United States, pig production distribution is significantly positively correlated with feed supply but not with regional market demand. This study concludes that distribution of pig production in China is more influenced by consumer demand and policies, whereas in the United States, feed supply capacity is the predominant driver force. China needs to develop appropriate policies to avoid concentrating pig farming in densely populated and ecologically fragile areas, to recoupling the crop and livestock production, without sacrificing the human- and ecosystem-health. • Analyzed the spatiotemporal trends of pig production in China and the United States from 1990 to 2017. • Identified China’s pig production expanding north, while the United States’ production stayed concentrated in the Corn Belt. • Revealed China’s pig production driven by demand and policy, while the United States’ production shaped by feed. • Provided region-specific strategies for sustainable pig production to secure pork supply and minimize environmental impacts.

  PublisherDOI

• Manure handling certification programs in manuresheds across the United States

  Cleaner Waste Systems · 2025-02-27

  articleOpen access

  Livestock waste can serve as a vital nutrient resource in agricultural production, but manure sources and potential users are often geographically separated due enduring economic forces. The challenges associated with the disconnection has resulted in a need for reform, inspiring the concept of the ‘manureshed.’ Successful manureshed management - optimally reconnecting those with manure surplus with those who can use it sustainably - requires effective education, outreach, and training, yet to date there has been no systematic evaluation of these programs. Our objectives were to enumerate and summarize the manure handling certification programs found throughout the United States (US), investigate relationships between state programs and major manure source locations, and present a case study focused on the efficacy of a market-based and voluntary statewide certification program. Twenty-six of fifty states have manure handling certification programs, the implementation of which are state-specific and highly variable (e.g., who requires training, whether certification is voluntary/mandatory). Certification is prevalent in regions with substantial manure hauling needs. Based on a case study in Wisconsin, providing state-level incentives for obtaining a manure handling certification had lower incidences of manure spills. Therefore, multi-state cooperation and standardization of manure handling certifications would be beneficial to the improvement of regional nutrient imbalances. • Exploration of current manure handling certification programs. • 26 out of the 50 US states have working programs. • Comparison among programs suggests implementation of programs is highly variable. • Based on a case study in Wisconsin, incentives may lead to a decrease of manure spills. • Adoption in other states could be considered to benefit from documented positive outcomes.

  PublisherDOI

• Recalibrating the Pennsylvania pre‐sidedress soil nitrate test recommendations for modern corn production

  Agronomy Journal · 2023-07-19 · 7 citations

  articleOpen access

  Abstract The pre‐sidedress soil nitrate test (PSNT) was developed over 30 years ago to determine sidedress nitrogen (N) fertilizer recommendations for corn ( Zea mays L.). Since the original PSNT calibrations were developed, changes in production practices such as no‐till and cover cropping and increases in corn yields and N use efficiency could affect the accuracy of PSNT recommendations. To update the PSNT recommendations in Pennsylvania and demonstrate the test's efficacy, we compiled a dataset of 32 calibration sites and 13 demonstration sites where the PSNT was conducted, and the economically optimum N rate (EONR) for corn was determined from an N fertilizer yield response curve. We recalibrated the PSNT recommendation algorithm and compared its accuracy to the original calibration. The new calibration resulted in a single long‐term manure history factor that interacted with the PSNT result to adjust the sidedress N recommendation (−5.7 kg N ha −1 [mg NO 3 ‐N kg −1 ] −1 ). The new calibration also included a term for a mixed species cover crop, which increased the sidedress N recommendation 56.2 kg N ha −1 . Finally, the coefficient that scales the N fertilizer recommendation based on yield goal decreased by 29% from the original calibration to 12.9 kg N Mg −1 grain. The new algorithm for predicting EONR reduced the error of the sidedress N recommendation by one‐half compared to the original calibration. The new PSNT calibration will allow users to accurately determine sidedress N recommendations in sites with a long‐term manure history and underscores the importance of updating soil fertility recommendation algorithms with modern data.

  PublisherOA PDFDOI

• Correction to “Discrepancies and Uncertainties in Bottom-up Gridded Inventories of Livestock Methane Emissions for the Contiguous United States”

  Environmental Science & Technology · 2023-02-15

  erratum

  ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionCorrection to "Discrepancies and Uncertainties in Bottom-up Gridded Inventories of Livestock Methane Emissions for the Contiguous United States"Alexander N. Hristov*Alexander N. Hristov*[email protected]More by Alexander N. Hristovhttps://orcid.org/0000-0002-0884-4203, Michael HarperMichael HarperMore by Michael Harper, Robert MeinenRobert MeinenMore by Robert Meinen, Rick DayRick DayMore by Rick Day, Juliana LopesJuliana LopesMore by Juliana Lopes, Troy OttTroy OttMore by Troy Ott, Aranya VenkateshAranya VenkateshMore by Aranya Venkatesh, and Cynthia A. RandlesCynthia A. RandlesMore by Cynthia A. RandlesCite this: Environ. Sci. Technol. 2023, 57, 8, 3455Publication Date (Web):February 15, 2023Publication History Received3 February 2023Published online15 February 2023Published inissue 28 February 2023https://doi.org/10.1021/acs.est.3c00941Copyright © 2023 American Chemical Society. This publication is licensed under these Terms of Use. Request reuse permissions This publication is Open Access under the license indicated. Learn MoreArticle Views390Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (950 KB) Get e-Alertsclose Get e-Alerts

  PublisherDOI

• Opportunities to implement manureshed management in the Iowa, North Carolina, and Pennsylvania swine industry

  Journal of Environmental Quality · 2022-03-03 · 19 citations

  articleOpen access1st authorCorresponding

  The U.S. swine industry is diverse, but opportunities exist to strategically improve manure management, especially given much of the industry's vertical integration. We investigate opportunities for improving manureshed management, using swine production examples in Iowa, North Carolina, and Pennsylvania as a lens into historical trends and the current range of management conditions. Manure management reflects regional differences and the specialized nature of hog farms, resulting in a large range of land bases required to assimilate manure generated by these operations. Selected representative farm scenarios were evaluated on an annual basis; farm-level manuresheds were largest for Pennsylvania sow farms and smallest for North Carolina nursery farms. Compared with nitrogen-based manuresheds, phosphorus-based manuresheds were up to 12.5 times larger. Technology advancements are needed to promote export of concentrated nutrients, especially phosphorus, from existing "source" manuresheds to suitable croplands. The industry is dynamic, as revealed by historical analysis of the siting of hog barns in Pennsylvania, which are currently trending toward the north and west where there is greater isolation to prevent the spread of disease and a larger land base to assimilate manure. Industry expansion should focus on locating animals in nutrient "sink" areas.

  PublisherDOI

• Monolith soil core sampling to develop nitrate testing protocol for manure injection

  Soil Science Society of America Journal · 2022-12-02 · 5 citations

  article1st authorCorresponding

  Abstract Injecting manure and commercial fertilizer beneath the soil surface is an important nutrient management practice that conserves ammonia‐nitrogen (N) but creates distinct bands of N below the soil surface. To date, no widely accepted soil nitrate sampling protocol has been developed to account for the extreme heterogeneity created by injection. To develop sampling recommendations for Pre‐Sidedress Nitrate Test (PSNT), we quantified patterns of NO 3 − ‐N concentrations in soil of corn ( Zea mays L.) plots injected with liquid dairy cattle ( Bos taurus L.) manure at 76 cm spacing over 2 years. Soil monoliths were collected to allow precise sampling of 30 cm deep by 2.5 cm soil cores from which a mid‐season PSNT was determined. Monte Carlo simulation was conducted to simulate the effects of alternative soil sampling protocols on bias and error. Results from the simulation support the following equispaced sampling protocol: five, 30‐cm deep soil cores are spaced 15 cm apart and oriented in a line perpendicular to the injected manure bands, collected at four locations in the field, to produce a single composite of 20 samples for NO 3 − analysis. It is not necessary to know manure band location. As spatially discrete manure application patterns become more prevalent with the expansion of manure injection, we believe this PSNT sampling protocol balances risk of error with practical concerns needed to promote adoption.

  PublisherDOI

• Manureshed management to overcome longstanding nutrient imbalances in US agriculture

  Resources Conservation and Recycling · 2022 · 27 citations

  • Environmental science
  • Business
  • Agroforestry

  The uncoupling of animal and crop production has resulted in long-term accumulation of manure nutrients in many areas, contributing to nutrient pollution. Prudent recycling of manure's nutrient resources requires reconnecting operations that produce manure with agricultural lands in need of nutrients. Thus the need to frame manure management via “manuresheds": the land (i.e. cropland, rangeland) surrounding livestock production operations where nutrients can be recycled on agricultural lands while balancing goals for production, environmental quality, and quality of life. We explore manureshed management as an evolution of national, regional, and local trends in nutrient sources and sinks. Results of our temporal assessments highlight not only system inertia, but the dynamic nature of nutrient flows and the potential for manureshed management to reverse nutrient imbalances at various scales. As a tool for a circular economy, manureshed management requires coordination beyond the farmgate, engaging specialists, industries, and other stakeholders.

  PublisherDOI

• Monolith Soil Core Sampling to Develop Nitrate Testing Protocol for Manure Injection

  2022-09-21

  preprintOpen access1st authorCorresponding

  Injecting manure and commercial fertilizer beneath the soil surface is an important nutrient management practice that conserves ammonia-nitrogen (N) but creates distinct bands of N below the soil surface. To date, no widely accepted soil nitrate sampling protocol has been developed to account for the extreme heterogeneity created by injection. To develop sampling recommendations for Pre-Sidedress Nitrate Test (PSNT), we quantified patterns of NO3–N concentrations in soil from of corn (Zea mays L) plots injected with liquid dairy cattle (Bos taurus L) manure at 76 cm spacing over two years. Soil monoliths were collected to allow precise sampling of 30 cm deep by 2.5 cm soil cores from which a mid-season PSNT was determined. Monte Carlo simulation was conducted to simulate the effects of alternative soil sampling protocols on bias and error. Results from the simulation support the following equispaced sampling protocol: five, 30-cm deep soil cores are spaced 15 cm apart and oriented in a line perpendicular to the injected manure bands, collected at four locations in the field, to produce a single composite of 20 samples for NO3- analysis. It is not necessary to know manure band location. As spatially discrete manure application patterns become more prevalent with the expansion of manure injection, we believe this PSNT sampling protocol balances risk of error with practical concerns needed to promote adoption.

  PublisherOA PDFDOI

• Poultry manureshed management: Opportunities and challenges for a vertically integrated industry

  Journal of Environmental Quality · 2021 · 42 citations

  • Business
  • Environmental planning
  • Agricultural economics

  Manureshed management seeks to address systemic imbalances in nutrient distributions at scales beyond the farmgate and potentially across county and state boundaries. The U.S. poultry industry, which includes broilers, layers, pullets, and turkeys, has many characteristics that are compatible with achieving a vision of manureshed management, including a history of engaging in local and regional programs to better distribute manure resources. Despite widespread vertical integration that supports large-scale strategic decision making and dry manures that favor off-farm transport, there are still many challenges to poultry manureshed management that require engaging stakeholders other than just the poultry industry. Analysis of county-level nutrient budgets highlights the industry's "mega-manureshed," extending from the Mid-Atlantic, across the southeast, and into northwest Arkansas, Oklahoma, and Texas. The analysis also identifies areas with legacy nutrient build-up that are still present today. Implementing manureshed management in the U.S. poultry industry requires comprehensive consideration of manure treatment technologies, alternative uses such as bioenergy production, market development for treated manure products, transport of manure nutrients from source to sink areas, and manure brokering programs that promote manure nutrient distribution. Fortunately, past and present evolution and innovation within the industry places it as a likely leader of the manureshed vision.

  PublisherDOI

• Manuresheds: Advancing nutrient recycling in US agriculture

  Agricultural Systems · 2020 · 143 citations

  • Environmental science
  • Agronomy
  • Agricultural science

  Nutrient recycling is fundamental to sustainable agricultural systems, but few mechanisms exist to ensure that surplus manure nutrients from animal feeding operations are transported for use on nutrient-deficient croplands. As a result, manure nutrients concentrate in locations where they can threaten environmental health and devalue manure as a fertilizer resource. This study advances the concept of the “manureshed” – the lands surrounding animal feeding operations onto which manure nutrients can be redistributed to meet environmental, production, and economic goals. Manuresheds can be managed at multiple scales, for example, on farms with both animals and crops, among animal farms and crop farms within a county, or even among animal farms and crop farms in distant counties. With a focus on redistribution among counties, we classified the 3109 counties of the contiguous United States by their capacity to either supply manure phosphorus (P) and nitrogen (N) from confined livestock production (“sources”) or to assimilate and remove excess P and N via crops (“sinks”). Manure nutrient source counties were identified in 40 of the 48 states, with a substantial concentration in the southern US. Source counties for manure P greatly outnumbered source counties for manure N (390 vs. 100), and 99 of the 100 manure N source counties were also source counties for manure P. Conversely, sink counties for manure N outnumbered sink counties for manure P (2766 vs. 2317). We used the P balances of the source and sink counties to delineate four manuresheds dominated by various combinations of confined hog, poultry, dairy, and beef industries. The four manuresheds differed in the transport distances needed to assimilate excess manure P from their respective source areas (from 147 ± 51 km for a beef dominated manureshed to 368 ± 140 km for a poultry dominated manureshed), highlighting the need for systems-level strategies to promote manure nutrient recycling that operate across local, county, regional, and national scales.

  PublisherDOI

Frequent coauthors

• Peter J. A. Kleinman

  Agricultural Research Service

  8 shared

• A.N. Hristov

  Pennsylvania State University

  6 shared

• John T. Spargo

  Pennsylvania State University

  6 shared

• Curtis J. Dell

  Waters (United States)

  5 shared

• Sheri Spiegal

  5 shared

• Troy Ott

  Pennsylvania State University

  5 shared

• G. C. Waghorn

  Massey University

  4 shared

• Felipe Montes

  Consejo Superior de Investigaciones Científicas

  4 shared

Education

• Ph.D., Agricultural and Biological Engineering

  Pennsylvania State University

  2006

• M.S., Agricultural and Biological Engineering

  Pennsylvania State University

  2002

• B.S., Agricultural and Biological Engineering

  Pennsylvania State University

  2000