Soil Chemistry

Aczel, M. R. "What Is the Nitrogen Cycle and Why Is It Key to Life?" https://kids.frontiersin.org/article/10.3389/frym.2019.00041, March 2019. This site discusses what the nitrogen cycle is and how it is necessary for soils and plants, which allow humans to live. It begins by explaining what nitrogen is and why it is so important to living things, as long as there is not an excess of nitrogen leading to eutrophication. The article then finishes by thoroughly explaining the nitrogen cycle as a whole, then each of the stages. In addition to being very reliable and accessible, the site has many references and sources sited, along with a well-credited author. Furthermore, the diagram aid in visualizing the nitrogen cycle and the glossary helps to simplify vocabulary, both making the website very understandable.

Bell, T. et al. "Understanding and Managing Soil Microbes" https://extension.psu.edu/understandingandmanagingsoilmicrobes#:~:text=Most%20soil%20microbes%20can%20be,to%20several%20billion%20bacteria%20alone, April 2021. 

This article discusses the variety of soil microbes, their function in maintaining healthy soils, and how farmers and other agriculturalists can best manage them for optimal plant health. Since the article is a basic overview of soil microbes, it is highly effective in educating the reader on the diverse functions of microbes, including nutrient cycling, nitrogen fixation, and decomposition. However, it lacks the specificity of a research paper. In addition, since the article is catered toward agriculturalists, the solutions provided for managing soil microbes are specific to farmers, such as soil steaming and tillage. The website lacks many visuals, a bibliography, and a point of contact, but does include links to sources from which the information is based. The article is written by a team of professors and graduate students of Penn State, meaning it most likely lacks any bias in its recommendations for how to care for plant health. Overall, this site receives a 7.5- on a scale of 1-10.

Binkley, D. et al. "Soil Chemistry in a Loblolly/Longleaf Pine Forest with Interval Burning.” https://www.jstor.org/stable/1941772?searchText=soil+chemistry&searchUri=%2Faction%2FdoBasicSearch%3FQuery%3Dsoil%2Bchemistry%26so%3Drel&ab_segments=0%2FSYC-6490%2Fcontrol&refreqid=fastly-default%3Adf99736bae6df257dc6ca4f9d67b7e32&seq=1, May 1992.

This article talks about a study that was done on soil. Scientists ran many tests for things such as PH, sulfur, magnesium, potassium levels, and more. The article goes into depth about how each chemical can affect the soil and test the differences in soil statistically. This article helps to bring an understanding of each of the chemicals that make the soil healthy and better for plant growth and is rated 7.6/10.

Biomed Central. “A golden period for environmental soil chemistry.”    https://geochemicaltransactions.biomedcentral.com/articles/10.1186/s12932-020-00068-6, April 2020.

This source offers a brief overview of soil chemistry as well as the intersection between soil health and climate change. The author highlights the importance of healthy soil to both the environment and the human population. The author also informs of some of the effects of climate change and environmental destruction on soil chemistry and soil health. This source is excellent for starting to understand the impact that soil chemistry has on things such as ecosystem diversity, food production, and environmental stability. This article contains a bibliography as well as the author's credentials which contributes to its reliability. 7.3+

Bojorquez-Quintal, E. et al. "Aluminum, a Friend or Foe of Higher Plants in Acid Soils" https://doi.org/10.3389/fpls.2017.01767, October 2017. 

This article discusses the role of aluminum in soil. It gives a brief explanation of aluminum and how the amount of aluminum present is dependent on the pH value of the soil. Soil with a lower pH will be more affected by aluminum, while soil with a higher pH value will be less affected. The site then talks about how aluminum can either aid or harm plant growth depending on how much aluminum is in the soil. It aids by boosting root growth in soils with low pH, but harms by inhibiting root growth in soils with a high pH. Overall, this site was very helpful in learning about how aluminum affects soil and plant growth. There were plenty of visuals and diagrams, and each credible author is listed at the top of the article. This site would get a 9- rating.

Chapman, S. “Soil Chemistry” https://www.soils4teachers.org/chemistry/, n.d. 

This source discusses the fundamentals of soil chemistry. It breaks down the different components of soil chemistry as well as links to further explore touched on topics. Some of the discussed topics are: Soil pH, which measures how acidic or basic the soil is, Sorption, a process where one substance holds another, and Redox Reactions. I would rate this website a 8.1 out of 10 as it provides a lot of useful information and relevant and clear images for anyone interested in learning about the basic overview of soil chemistry. This article explains various aspects of soil chemistry making it very useful for more in-depth E.S.S.R.E. research.

Climate Woodlands. "Basic soil components" https://climate-woodlands.extension.org/basic-soil-components/, May 2019. 

This website covered the basic makeup of soil stated in a simple easy to follow format. Climate, Forests and Woodlands broke the basics of soil into five separate categories. Within these categories they provided a perfect introduction explaining how different factors contributed to the overall contents of soil. Although the website did lack in organization. The information was just on one long webpage only broken up by underlined titles. The introduction of the website tells the reader about how "soil is simply a porous medium consisting of minerals, water, gases, organic matter, and microorganisms", then the webpage goes more in-depth on all of those factors and the roles they play within the soil (Basic Soil Components). 8.2- is the score this website earned, while it is perfect to give you a basic understanding of soil chemistry, it is a generally basic definition.

Culman, S. et al. "Calculating Cation Exchange Capacity, Base Saturation, and Calcium Saturation" https://ohioline.osu.edu/factsheet/anr-81, August 2019. 

When discussing the field of soil chemistry this site was a helpful resource. The source reviews cation exchange capacity, base saturation, and calcium saturation as essential properties within soil. It begins by explaining how cation exchange capacity helps to measure how much nutrients are available within the soil. They go on to explain how both cation exchange capacity and base saturation work together to help people regulate soil fertility. The source had many helpful diagrams and pictures to help the reader understand the text. The work was seemingly written for this within the chemistry field making the text slightly confusing, but it does offer a short summary to give its readers a better idea. This site received an 8.9-/10.

Dobbs, C. et al. "Landscape and Urban Planning" https://www.fs.usda.gov/research/treesearch/39207, 2011. 

This document is part of a journal that is focused on urban landscaping. It was written by three authors, Dobbs, Escobedo, and Zipperer. It was created in 2010, which is kind of in the middle of recent and too old to consider a valuable source. This document was written to exemplify the importance of using indicators to study urban soil and understand how urban forests impact people near them. An experiment was performed to study the factors of biodiversity and morphology of urban forests. The experiment also hypothesized that socioeconomics can or cannot? play a factor in the health of these forests. The final outcome displayed that urbanization of the area that was experimented on, most affected the soil's pH and organic matter, as well as tree cover. Overall, this study presented an interesting view on how urban development can affect the soil in these areas, as well as how the usage of indicators is important in keeping urban forests healthy. This document scored an 8.66+ on a score of 1-10.

Environmental Protection Agency. “Indicators of Soil Chemistry” https://www.epa.gov/national-aquatic-resource-surveys/indicators-soil-chemistry, June 2024. 

This source gives an overview of what soil chemistry is, as well as the importance of it in relation to different ecological conditions. This article focuses on how wetland areas have different amounts of chemicals and nutrients compared to other biomes. While giving the background as to why soil chemistry is important, this source also answers the question of what soil chemistry can be used for in order to determine different aspects in our surrounding environments. As a source from the United States Environmental Protection Agency, this was a reliable and informational site earning an overall score of 8.2+.

Gashler, K. "Newly found bacteria fights climate change, soil pollutants" https://news.cornell.edu/stories/2020/02/newly-found-bacteria-fights-climate-change-soil-pollutants, February 2020. 

This article discusses the findings and functions of a newly discovered soil bacteria. Information in the article is split between the background of the scientist who discovered the bacteria, Gene Madsen, and the function of the new microbe in soil. The article does not go into much detail but does explain that the new microbe, madseniana, plays a key role in the decomposition of a pollutant known as polycyclic aromatic hydrocarbons. While there is no bibliography, there are links to the initial research paper about the discovery of madseniana, as well as links to the other researchers on the team. This resource would be best for an outsider to learn about the importance of bacteria in soil or any reader to learn about the process of discovering madseniana. Though the article lacks many visuals, its content is concise and provides a good balance of specificity for more intermediate readers while maintaining simplicity. This article receives a 7.4+ on a scale of 1-10.

Guiser, S. “Don’t Guess… Soil Test” ​​https://extension.psu.edu/dont-guess-soil-test, March 2023. 

This material was produced by a former educator in Pennsylvania State University. In this website it explains the importance of testing your soil, the elements you may find within the soil & the things you can measure in the process of testing your soil. This website also provides a list of procedures of how to complete a soil test. As well as providing their own results from the students of Pennsylvania State University. This website is useful because it links several sources for the things you need to learn about soil testing. 9/10.

Heckman, J. "Sulfur Nutrition and Soil Fertility Management for New Jersey Crops." https://njaes.rutgers.edu/e365/, February 2021. 

This article is a valuable source when researching soil chemistry. It gives beneficial information on sulfur as a necessity for soil life and plant health. The site discusses how the presence of sulfur in soil positively affects plant disease resistance and crop quality. It also explains how the sulfur supply can vary depending on soil properties because of how the different soils retain sulfate. The article presented helpful charts, pictures, and simplified summaries to better help the reader when understanding the text. The work was given with an educational tone, so if needed for research this source would be an excellent choice. This site received an 8.5+/10.

Jayapalan, C. “Soil Protozoa, a Microbial Indicator of Soil Health: A Review” https://juniperpublishers.com/aibm/pdf/AIBM.MS.ID.555700.pdf, October 2017. 

This article covers the role of protozoa in maintaining ecological diversity and indicating soil health. The article begins by discussing how protozoa are influenced by different external factors, and later shifts to discuss where different classifications of protozoa are most dominant due to their needs. In addition, the article discusses the importance of protozoa in maintaining soil moisture, acidity and other indicators of well-being. The article lacks visuals, but is a good resource for intermediate to moderately advanced readers seeking to learn more about the prevalence of different kinds of protozoa in specific environments. In addition, the source includes a bibliography for further research. Overall, this article receives an 8.0+ on a scale of 1-10.

Jenkins, A. “Soil Fungi” https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0020/41645/Soil_fungi.pdf, 2005. 

This article covers the types of soil fungi, their functions, their habitats, and how to promote the growth of soil fungi. The article goes into more depth than a basic overview by providing information on the physical structure of various types of soil fungi, including the scientific names of organisms. This resource is beneficial in educating the reader on where fungi grow and how to protect it, so it would be most beneficial for farmers and beginner biologists. Though the article is written by an unbiased source, it does encourage the reader to reduce fungicide and herbicide use. While the writing could stand to be improved, it is generally a helpful source for beginner to intermediate readers. The article provides links to additional information for the reader to further their knowledge of soil biology, but does not include a bibliography. Overall, this article receives a 7.17- on a scale of 1-10.

Knoepp, J. D., DeBano, L. F., & Neary, D. G. (2022). “Chapter 3: Soil Chemistry”. In: Neary, Daniel G.; Ryan, Kevin C.; DeBano, Leonard F., Eds. 2005. Wildland Fire in Ecosystems: Effects of Fire on Soils and Water. Gen. Tech. Rep. RMRS-GTR-42-Vol.4. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 53-71., 42, 53-71. Retrieved July 14, 2025, from https://research.fs.usda.gov/treesearch/45941

This article aims to educate people on how fire affects the soil’s chemical characteristics. The article effectively explains the complex concept of soil’s chemical changes post-fire, stating,  "The soil chemical characteristics are most commonly affected by fire," and talking mostly about the specific chemical reactions that the soil undergoes. This article clearly explains what chemical changes occur and how these transformations take place between fire’s and soil chemistry. The concise nature of the article’s explanation, as well as a deliberate absence of unnecessary jargon, leaves this website to be an exceptionally easy and user-friendly resource, ensuring that those without any prior knowledge can learn the basics of how fire affects soil chemistry. This article gets an 8- on a scale of 1-10.

Kressy, M. "Down to Earth Talk About Soil Chemistry" https://www.nytimes.com/1976/04/18/archives/down-to-earth-talk-about-soil-chemistry-down-to-earth-talk-about.html?searchResultPositionno=1, April 1976.

In the article it discusses the levels of pH and other chemicals such as iron, hydrogen, and oxygen in the soil. It describes the relationship between the soil and the chemicals. Certain levels of each chemical are needed to provide healthy soil for plant growth. In the article it talks about something called pores or spaces within the soil. The pores allow for things such as hydrogen and oxygen to travel throughout the soil and be able to reach root systems so that they can take it in. This is essential to plant growth so that each plant can get the nutrients and chemicals they need to photosynthesize. This is helpful to better understand the relationship between the soil, root systems, and chemicals and is rated 7/10.

KSKL “Teacher Guide | Soil Chemistry Overview.” (n.d.). https://www.soils4teachers.org/files/s4t/In-Service%20Materials/soil-chemistry-overview.pdf

This PDF document serves as an exceptional guide for teachers to follow, offering a comprehensive and accessible overview of soil chemistry. Its primary goal is to equip teachers with the tools to effectively teach a class on the fundamentals of soil chemistry,  creating a broad overview and introduction to the chemicals that make up soil. This guide is split into many key subtopics, including "Ion Exchanges"and "Soil pH", and many more topics. What sets this resource out is the amount of relevant images that vividly illustrate complex topics of soil chemistry, making the intricate details much easier for students to grasp. It is clearly designed with the teacher in mind, creating a source that simplifies the material without sacrificing the overall depth. This site gets a 9+ on a scale of 1-10.

Kumaragamage, D. et al. "Soil Chemistry." https://geo.libretexts.org/Bookshelves/Soil_Science/Digging_into_Canadian_Soils%3A_An_Introduction_to_Soil_Science/01%3A_Digging_In/1.05%3A_Soil_Chemistry, n.d. 

This article is an in-depth explanation on soil chemistry and how it involves multiple different areas of study, such as chemical composition, chemical properties, and chemical reactions. Chemical reactions involve soil solids, liquids, and gases, and how it interacts with plants and organisms in the soil. I would rate this website a 7.9 out of 10 as it is very helpful for people who have previous knowledge of soil chemistry the article has reputable authors, however it is very lengthy and has complex vocabulary, which can make it difficult to understand. The comprehensive research in this source is very useful when interning at E.S.S.R.E.

Leeper, G. W. & Uren, N. C. “What Is Soil?” https://agriculture.vic.gov.au/farm-management/soil/what-is-soil, March 2024. 

This website discusses several focusing points within Soil Chemistry. Which consists of Physical Characteristics of Soil, Soil Texture, Soil Structure, Soil Colour, Organic Components etc. This material goes way in depth about each focusing point and explains what it means. It also provides measurement units and indicators for each topic. Overall, the reliability of this article is very strong and dependable. 8/10

Lerner, B. W. & Lerner, K. L. "Soil Chemistry” The Gale encyclopedia of science by K. Lee Lerner | Open Library , 2009. 

This article covers the nutrients present in the soil such as humus which provides minerals for the microbial community. The particle size of the soil can vary depending on the soil's ability to accumulate water. Although weathering can produce soil through the underlying rocks, this process takes a very long time and soil erosion happens quicker than the soil is being created, leaving eroded soil as sentiment and creating issues for nearby aquatic systems. This site includes over 10 links to related topics mentioned in the article allowing for further research to be seamlessly conducted. Although published in 2009, the information seems to remain relevant and accurate to today's understanding of soil. The author, Brenda Wilmoth, is well-versed in the community as she attended Harvard University and achieved many impressive accomplishments. The information within the article is at a level of complexity, but not incomprehensible. Overall, this article has valuable and useful information.

Margenot, A. "What is soil chemistry and what does that mean to me?" https://soilsmatter.wordpress.com/2016/05/01/what-is-soil-chemistry-and-what-does-that-mean-to-me/, May 2016. 

Soils Matter gave a fantastic definition and explanation of what soil chemistry is and how it is used. Even though this website was written slightly informally it still has valuable information about soil chemistry. Informitive visuals can be seen throughout this article. They do a great job breaking down the information in an easy-to-understand format. Not only is a basic overview of soil chemistry provided, but this website gives detailed information about soil chemistry. It explains the different properties and the reactions that occur within soil. Altogether, this website was an excellent source of information. Soils Matter earned 8- for its straightforward writing format and descriptive visuals.

Melillo, J. & Gribkoff, E. "Soil-Based Carbon Sequestration." https://climate.mit.edu/explainers/soil-based-carbon-sequestration, April 2021. 

When researching different qualities of soils chemistry this source would be of significant help.. The article presents intriguing insights into how soil's impressive carbon retention can be a detriment to climate change as farmland unsettles soil forcing it to release its stored carbon into the atmosphere. It states that fighting against this addition to climate change would be near impossible as it challenges farmers to change the way they have been working for years. They would have to find a completely new way to farm. The article also discussed how soil could be used in the fight against climate change by utilizing the same qualities that once contributed to that issue. This source posed both a problem and a solution using the same quality within soils chemistry, bringing awareness to an issue that most people may not be aware about. This site received an 8.2+/10.

Minnesota Pollution Control Agency. "Soil chemical properties and processes" https://stormwater.pca.state.mn.us/index.php?title=Soil_chemical_properties_and_processes, December 2022. 

This website has in-depth information on soil chemistry and soil chemical properties. The site first briefly discusses different soil chemical properties, such as specific concentrations of chemicals and elements, salinity, base saturation, and enzymes. These properties can affect many different soil processes as well, such as nutrient cycling, soil formation, and erosion. The site goes on to individually list many different soil chemical properties and how they specifically affect soil processes. Elements such as nitrogen, phosphorus, and sulfur are listed and described. For example, the site describes how phosphorus is often a limiting nutrient in the soil and contributes to about 0.2 percent of a plant’s dry weight. The website continues to similarly describe different individual soil chemical properties. This website is helpful for finding how specific chemicals and other properties affect soil chemistry and processes. This has a rating of 9+.

NCRS East National Technology Support Center, et al. "Nutrient Cycling" http://soilquality.org/functions/nutrient_cycling.html#:~:text=Soil%20stores%2C%20moderates%20the%20release,lost%20to%20air%20or%20water, September 2011. 

The website begins by describing how soil processes nutrients through nutrient cycling. Soil stores, releases, and cycles nutrients and elements to either be held by the soil, made available to plants, or released into air or water. The site lists and briefly explains indicators for measuring and assessing nutrient cycling. The site mentions three different indicators, soil fertility, soil reaction, such as soil pH, and organic matter. The final paragraph describes the relationship between carbon dioxide and soil. Soil carbon is in the form of organic compounds created in photosynthesis, such as carbohydrates and proteins, that enter the soil when plants and animals die. Soil organisms immediately begin consuming the organic matter, releasing heat energy, water, and CO2 into the atmosphere. The site does an eloquent and simple job of explaining the information. It also displays it in an easy-to-read way along with a helpful diagram. This has a rating of 8.5+.

Nutrient Economics. "The Chemistry of Soil pH" www.nutrien-ekonomics.com/news/the-chemistry-of-soil-ph/, n.d. 

This source goes into detail about the different types and effects of pH in soil, specifically its effect on soil productivity and nutrient absorption. While diving into pH this article also talks about nitrogen as well as different pools of soil acidity. It also touches on how harvesting crops can affect a soils’ pH and even chemical composition within the soil. Although this source does not contain many citations or information about the authors and editors, the content of this article is thorough and easy to navigate. Overall this is a great resource for researching soil pH, with a score of 8.6-.

Ontl, T. A. & Schulte, L. A. "Soil Carbon Storage" https://www.nature.com/scitable/knowledge/library/soil-carbon-storage-84223790/, 2012. 

This site discusses what the carbon cycle is and its importance in the role of carbon storing withing the soil. It begins by explaining how soil organic carbon and carbon dioxide contribute to ecosystems as a whole. Then it goes into more detail about how they play a large role within climate change and sequestration. This website includes visuals, charts, and diagrams with sources sited and references at the bottom, making the website very accessible. While each of the sections are very dense with material, it helps to thoroughly explain with details to make the content easier to comprehend.

Oregon State University. "Discuss the major elements needed for good soil fertility and plant growth.” https://forages.oregonstate.edu/nfgc/eo/onlineforagecurriculum/instructormaterials/availabletopics/fertilization/elements, n.d.

This site provides information on the importance of different chemical elements in soil fertility and plant growth. It has summaries on the effects of nitrogen, phosphorus, potassium, and sulfur, and also explains how to test soil for these nutrients. It describes nitrogen as “the most critical element for grass plants” because it aids in soil fertility and plant growth. This site is very helpful for understanding the major elements in soil and how they help the growth of plants. The website has clear and concise information but lacks visuals and graphics. Overall this website would be rated an 8+.

Prasad, R. & Chakraborty, D. "Phosphorus Basics: Understanding Phosphorus Forms and Their Cycling in Soil.” https://www.aces.edu/blog/topics/crop-production/understanding-phosphorus-forms-and-their-cycling-in-the-soil/?cn-reloaded=1, April 2019. Score: 8.9-. 

This is an article published by Auburn University and Alabama A&M University on Phosphorus. The article details specifically the molecular forms of phosphorus that can be found in soil. It goes into depth about the phosphorus cycle, and how phosphorus becomes available to plants or unavailable to plants depending on whether they are inorganic or organic. The types of processes involved in the phosphorus cycle are explained, as well as the factors that contribute to loss or availability of phosphorus. Finally, the article ends with several paragraphs explaining the components of phosphorus that are in soil and how they relate to one another.

Robbins, P. "Soil Science" https://go.gale.com/ps/i.dop=GRNR&u=balt23720&id=GALE|CX2660701020&v=2.1&it=r&sid=bookmark-GRNR&asid=18dbb3c7, 2007. 

This article discussed the organic chemical reactions that occur in the soil and their effect on soil systems. They defined soil biology as addressing topics such as soil organic matter, nitrogen fixation, organism populations, habitat, and pesticides. The green revolution allowed for advancements in soil science because agricultural productivity increased allowing for these advancements to occur. Despite being written in 2007, the information remains viable and the institution which published this work continues to uphold its reputation of reliable research. This website was easily navigated with many links and headings making each section and subsection clear. The author is well renowned as he has written a popular educational textbook Political Ecology, and contributed to numerous research expeditions.

Royal Horticultural Society. "pH and Testing Soil" www.rhs.org.uk/soil-composts-mulches/ph-and-testing-soil, n.d. 

In this source, researchers share their data regarding soil pH and soil testing. This ranges from why it is important to test soil pH to stating the different types of soil and their average pH and chemical levels. This article gives an introduction to soil and pH testing as well offering information to understand why testing pH is so important for the environment. Understanding pH levels within soil allows for researchers to identify different types of soil and the ranging amounts of nutrients and bacteria present. Although lacking author credentials and a bibliography, an 8.3+ is the overall score for this source.

Schulte, E. E. "Soil and Applied Chlorine" http://corn.agronomy.wisc.edu/management/pdfs/a3556.Pdf, 1999. Score: 8—. 

This pdf was published by the University of Wisconsin in 1999. The author refers to the fact that some things concerning chlorine are unknown, and this may no longer be true at the time a reader is reading this article, though it may have been true in 1999. The article explains the forms of chlorine in soil and its function in plants, but mainly describes how it is available to plants and in what circumstances a chlorine deficiency may take place. The article takes a few sentences every so often to explain how this information applies to Wisconsin, but it also takes a few sentences to explain how an area near a coastline may see different levels of chlorine in their soil. As Baltimore borders the Chesapeake bay and is split by the Atlantic Coastal Plains, this is relevant information for E.S.S.R.E..

Schultheis, L. et al. "Soil Chemical Properties" https://soilhealthnexus.org/resources/soil-properties/soil-chemical-properties/, March 2020. 

Soil Health Nexus was an extremely helpful website. It started off with a brief explanation explaining how different factors can affect "the release of specific nutrients" within the soil (Soil chemical properties). Then, the website broke down into separate links. Each of these links lead to information that gave detailed information regarding different aspects of soil chemistry. For the most part, the explanations made sense; Although, at times it was a little overcomplicated. Within this site were many fantastic images and diagrams. This truly was a fantastic site. It contained an incredible organized list of links that lead to information about different topics about the chemistry of soil. Overall, this was an incredible site and Soil Health Nexus earned a 8.8+ because of its extremely well-organized information.

Science. “Soil and human security in the 21st century.” https://www.science.org/doi/10.1126/science.1261071, May 2015.

This article offers insight into some of the challenges that soil faces today and its effects on human stability . The source comments on the importance of healthy soil for things such as food security and environmental security as well as the direct correlation between soil health and population health. It also offers an overview of the stress that human destruction has placed on global soil. The article is well referenced and contains many figures to assist the reader in comprehending the subject matter. 8.0-

Soil Science Society of America. "Soil Fertility" https://www.soils4teachers.org/fertility, n.d. 

This site discusses how plants require difference nutrients to survive and how different nutrients are often managed within the soil in order to try to create a positive outcome and allow the fertility of the soil to increase. This can also be accomplished by giving the plants chemicals that can alter the pH levels. The site continues to show the relationship between pH and nutrient availability with a graph and describe the essential nutrients to plants with a chart that explains how to tell when a plant needs more of this nutrient. The site then discusses factors that one must reflect on before starting to grow plants and factors that affect the sustainability of producing plants. While there are no references or authors credited within this page, the site is very accessible because the charts and visuals help to explain and visualize the material within the article, making it overall easier to comprehend.

Sparks, D. L. “A Golden Period for Environmental Soil Chemistry” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7114811/, April 2020. 

This website more so focuses on the history of Soil Chemistry and how it has changed over the years. It is mentioned in the article that Soil Chemistry has impacted the environment in various ways. In some ways such as climate change, weather events and even food supply. So many people were given recognition for studying Soil chemistry because it can sometimes be such a challenge to learn. This website provides easy access to other references that fall under the category of Soil Chemistry. 7/10.

Sparks, D. L. "Fundamentals of Soil Chemistry" https://doi.org/10.1002/9781119300762.wsts0025, October 2019. 

This article discusses soil chemistry which tackles the chemical composition and chemical reactions of plants and soil nutrients. The ideal environment for soil is important in soil growth as if carbon dioxide is present in the air and comes in contact with the soil it will prohibit the soil's ability to thrive and grow. The inorganic components in the soil can consist of primary and secondary minerals. This can include quartz or feldspar. This database was published in 2019 and therefore it is relevant. It is credible because this article is from the book, Encyclopedia of Water, which was published by distinguished author Donald Sparks. The book and article have many references and a long list of other research databases that were used during the writing process.

Texas A&M University. "Soil chemistry & Fertility" https://soilcrop.tamu.edu/program/soil-chemistry-fertility/, n.d. 

This website contains a wonderful overview of what soil chemistry is and how it is used. A definition of soil chemistry and how "traditional soil chemistry (soil fertility) focuses on chemical and biochemical reactions in soils that influence nutrient availability for plant growth" was provided and very useful ("Soil chemistry & fertility"). The chemistry of soil is not only related to what is already in it, but how it has been changed through fertilizers added by humans. Through the study of soil chemistry, a "more fundamental understanding of chemical and biochemical reactions in soils" is learned and used to help the overall sustainability and environmental quality of communities. All in all, this was a helpful website; even though it was fairly short it contained quality information provided in an easy to comprehend format. Overall, this website earned a 7.7- as its score out of 10. For the most part, it was a quality source although it lacked visuals and in-depth information regarding soil chemistry.

The University of Adelaide, The Mosaic Company. “Technical Bulletin: Sulfur in Soils” https://sciences.adelaide.edu.au/fertiliser/system/files/media/documents/2020-01/factsheet-sulfur-in-soils.pdf, n.d. Score: 9.6 +. 

This pdf from the Adelaide University in Australia explains how sulfur ends up in soil, behaves in soil, is essential for plants, and what factors including leeching can contribute to sulfur deficiency. Though the last few paragraphs were dedicated specifically to care for crops that may be sulfur deficient, the earlier paragraphs held important information about sulfur in soil and in plants.

US EPA, O.Indicators: Soil Chemistry. (2014, January 10).  www.epa.gov. https://www.epa.gov/national-aquatic-resource-surveys/indicators-soil-chemistry 

The goal of the article is to give students and other people interested in soil chemistry a brief analysis of its intricacies, as well as experiments that the Virginia Department of Conservation and Recreation has conducted. The site starts by providing a brief definition of what soil chemistry is, as well as why it is important to evaluate soil chemistry.  The short definitions at the beginning of the paper are helpful for giving an easy-to-understand source of context. While the few images on the website don't necessarily explain the text further, they still connect to the topic and help break up the text to make it less overwhelming. It also provides an insight into what will be happening on the later website pages. Overall, this website gets a 9- on a scale of one to 10.

Virginia Department of Conservation and Recreation. “Basic Soil Chemistry Soil Science.” (n.d.). Retrieved July 14, 2025, from https://www.dcr.virginia.gov/soil-and-water/document/nmagscbsc.pdf

The goal of the PDF document is to educate people about soil chemistry, covering various topics related to the chemicals that comprise soil. Some of these topics include "How does CEC Affect Nutrient Availability?" ("Basic Soil Chemistry" 26), "How does Nutrient Uptake Occur?" ("Basic Soil Chemistry"19), and "How Nutrients are Held." ("Basic Soil Chemistry" 14). This PDF is split into many subtopics, each one covering a different aspect of soil chemistry, including Basic Soil Chemistry, Properties of Colloids, types, distribution, and sources of Charge, Organic Matter, Nutrients, cellular make-up, and many more topics. This PDF seems to be made to be either a packet/handout or a slide show to take a class through a unit of learning about soil chemistry. The abundance of relevant images makes the material easy to understand. This PDF gets a 8.5- on a scale of 1-10.

Waring et al. “Pervasive and strong effects of plants on soil chemistry: a meta-analysis of individual plant 'Zinke' effects.” https://doi.org/10.1098/rspb.2015.1001, 2015. 

This source goes in depth into the research surrounding plant-soil interactions. It discusses the biogeochemical effects of these interactions on both a large and small scale. This is a dense source with an incredible amount of information on both the general science of these interactions and the individual research that is being conducted. While it does provide excellent information, it also is very detailed and may require assistance to ensure full comprehension. 7.6-

Yesilonis, I. "Changes in Soil Chemistry After 17 Years in Urban and Rural Forest Patches" https://www.frontiersin.org/articles/10.3389/fevo.2022.786809/full, February 2022. 

This is a great resource for understanding the differences in chemical makeup between urban and non-urban forest soils. It is a long-term study that chose to specifically highlight the different amounts of chemicals that make urban soil healthy in comparison to other soil. This study displayed results in an orderly manner and clarified each meaning. The organization in charge of this website specializes in ecology legitimizing their argument. This study was well done and notable. getting its point across, and it is a great resource for anyone studying urban soil. This study was done in Baltimore, adding to its benefit as a source for E.S.S.R.E. research. This article gets a 9.3+ on a 1-10 scale.