Bulk soil

<h2 id="chemistry-of-bulk-soil">Chemistry of bulk soil</h2>
<p>Soil is made up of layers called <a href="/facts/Soil_horizon/GcXhdams">soil horizons</a>, these make up a vertical soil profile. There are five master horizons O, A, E, B, and C. The O horizon contains <a href="/facts/Organic_matter/t17tVCvk">organic matter</a>, A is considered the <a href="/facts/Topsoil/BDClBQrs">topsoil</a>, E is present or absent depending on the type of soil and conditions, B is the <a href="/facts/Subsoil/URWLX60v">subsoil</a>, and C is unconsolidated <a href="/facts/Rock_(geology)/FXCJkmop">rock</a>. There are many chemical interactions and properties that are in all the soil. Chemical properties of the bulk soil are <a href="/facts/Organic_matter/t17tVCvk">organic matter</a>, <a href="/facts/Carbon/ukrgQexo">carbon</a>, nutrient content, <a href="/facts/Cation-exchange_capacity/4DoXx9Jk">cation-exchange capacity</a> (CEC), free ions (cations or anions), <a href="/facts/PH/RnSv8D7y">pH</a>, and base saturation and <a href="/facts/Organism/j8JkL09u">organisms</a>. These can impact many chemical processes such as <a href="/facts/Nutrient_cycling/S57nuGbQ">nutrient cycling</a>, <a href="/facts/Soil_formation/sJty93z9">soil formation</a>, biological activity, and <a href="/facts/Erosion/gaGJXy0W">erosion</a>.
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<h2 id="microbial-communities">Microbial communities</h2>
<p>Soil is composed of a diverse community of microbes such as: <a href="/facts/Fungi/BHo5DP59">fungi</a>, <a href="/facts/Bacteria/wC8xSCsU">bacteria</a>, <a href="/facts/Archaea/Adxh0aHw">archaea</a>, <a href="/facts/Virus/mf88Bcbl">viruses</a> and <a href="/facts/Microfauna/C6whJqKQ">microfauna</a>. There are microbes in the bulk soil and the rhizosphere, the variation of microbes increases in the bulk soil and the abundance of microbes increases in the rhizosphere. Some microbes can form <a href="/facts/Symbiosis/MrBArRGa">symbioses</a> with plants that are beneficial or <a href="/facts/Pathogen/axMXtV1M">pathogenic</a>. All these microbes have a special role in many soil processes such as soil formation, organic matter decomposition, nutrient cycling.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> For example, there are microbes in the rhizosphere (on the plant) that can break down <a href="/facts/Nitrogen/Nf1QpGDz">nitrogen</a>, and microbes out in the bulk can break down nitrogen as well. Both have different factors that affect this process. 
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<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Stotsky, G. (2000). Soil Biochemistry. CRC Press. p. 207. ISBN 978-0-8247-9441-5. Volume 9. <a href="978-0-8247-9441-5" target="_blank">978-0-8247-9441-5</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Stotsky, G. (1996). Soil Biochemistry. CRC Press. p. 234. ISBN 978-0-8247-8834-6. Volume 10. <a href="978-0-8247-8834-6" target="_blank">978-0-8247-8834-6</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Liu, Zhuxiu; Gu, Haidong; Yao, Qin; Jiao, Feng; Liu, Junjie; Jin, Jian; Liu, Xiaobing; Wang, Guanghua (2022-09-01). "Microbial communities in the diagnostic horizons of agricultural Isohumosols in northeast China reflect their soil classification". CATENA. 216: 106430. Bibcode:2022Caten.21606430L. doi:10.1016/j.catena.2022.106430. ISSN 0341-8162. S2CID 249596682. <a href="https://www.sciencedirect.com/science/article/pii/S0341816222004167" target="_blank">https://www.sciencedirect.com/science/article/pii/S0341816222004167</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
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Bulk soil open-in-new

Bulk soil