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The Science of Soil: Understanding its Composition and Importance

By May 27, 2023Land, Uncategorized

Understanding the composition of soil is crucial for optimizing agricultural practices, promoting sustainable land management, and addressing global food security challenges. Here, let’s briefly explore how soil texture, organic matter, pH, nutrients, and soil structure play a role in composition.

First, soil texture refers to the relative proportions of sand, silt, and clay particles in the soil. Texture influences the soil’s physical properties, such as water-holding capacity, drainage, and aeration. The USDA’s Natural Resources Conservation Service provides a comprehensive guide on soil texture classification (1). Knowledge of soil texture helps determine suitable crops, irrigation strategies, and soil management practices. For example, sandy soils with low water-holding capacity may require more frequent irrigation and organic amendments to enhance their fertility (2).

Next, organic matter is a critical component of soil composition, derived from decomposed plant and animal materials. Organic matter plays a vital role in soil fertility, structure, nutrient cycling, and microbial activity. The presence of organic matter improves soil water-holding capacity, nutrient retention, and resistance to erosion. Researchers (Lal, 2004) have highlighted the importance of maintaining and increasing organic matter content in soils to enhance productivity and sustainability (3). Practices such as cover cropping, composting, and reduced tillage promote organic matter accumulation in soils (4).

Soil pH is a measure of its acidity or alkalinity, which influences nutrient availability to plants. Different crops have specific pH requirements for optimal nutrient uptake. Adjusting soil pH through amendments can improve crop productivity. A study by Schachtman and Shin (2007) highlights the importance of understanding soil pH in nutrient management (5). Soil testing laboratories and extension services provide guidance on soil pH testing and recommended amendments for specific crops and regions. Soon I will be adding some Resources to this website that will include some Extension articles. As I always say, I am not an expert but merely a land advisor. Extension agents are an incredibly helpful resource. They are the experts, and I would encourage you to reach out to your county Extension office for specific questions and/or information.

Next, let me mention nutrient composition. Soil serves as a reservoir for essential nutrients required by plants. Macronutrients (nitrogen, phosphorus, and potassium) and micronutrients (iron, zinc, etc.) are essential for plant growth and development. Assessing nutrient composition through soil testing allows farmers to make informed decisions on fertilization strategies. Nutrient management plans based on soil testing help optimize nutrient application, reduce environmental impacts, and ensure sustainable agriculture. Research by Havlin et al. (2014) provides comprehensive insights into nutrient management principles (6).

Finally, soil structure refers to the arrangement and aggregation of soil particles, influencing root growth, water movement, and aeration. Well-structured soils promote root penetration, enhance water infiltration, and prevent erosion. Soil compaction, organic matter content, and biological activity significantly impact soil structure. Practices such as crop rotation, cover cropping, and conservation tillage help maintain or improve soil structure. Lal (2015) emphasizes the importance of soil structure in sustainable land management (7).

In the end, understanding the composition of soil is essential for sustainable land use and agricultural practices. By considering soil texture, organic matter content, pH level, nutrient composition, and soil structure, farmers and land managers can make informed decisions to improve soil quality, increase agricultural productivity, and preserve the environment. By applying scientific knowledge to soil composition, we can ensure the wise stewardship of this valuable resource, promoting a sustainable future for generations to come.

Invest. Grow. Conserve.


  1. USDA-NRCS. (n.d.). Soil Texture. Retrieved from
  2. Brady, N.C., Weil, R.R. (2016). The Nature and Properties of Soils. Pearson.
  3. Lal, R. (2004). Soil carbon sequestration to mitigate climate change. Geoderma, 123(1-2), 1-22.
  4. Blanco-Canqui, H., Lal, R. (2009). Crop residue removal impacts on soil productivity and environmental quality. Critical Reviews in Plant Sciences, 28(3), 139-163.
  5. Schachtman, D.P., Shin, R. (2007). Nutrient sensing and signaling: NPKS. Annual Review of Plant Biology, 58, 47-69.
  6. Havlin, J.L., et al. (2014). Soil Fertility and Fertilizers: An Introduction to Nutrient Management. Pearson.
  7. Lal, R. (2015). Soil health and carbon management. Food and Energy Security, 4(2), 117-126.

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