#### 34990A soil scientist is analyzing three plots of land to compare soil organic matter content. Plot A has 2.4% organic matter by weight, Plot B has 3.1%, and Plot C has 1.9%. She collects a 500-gram soil sample from each plot and mixes them all into a composite sample. What is the percentage of organic matter in the composite sample?
["Title: How to Calculate Average Soil Organic Matter in a Composite Sample: A Case Study with Plots A, B, and C", "Understanding soil organic matter (SOM) content is crucial for assessing soil fertility, carbon sequestration, and long-term agricultural sustainability. When soil scientists collect samples from multiple plots, accurately calculating the weighted average organic matter content helps provide reliable insights. In this article, we explore how to determine the organic matter percentage in a composite sample drawn from three distinct plots—Plot A (2.4%), Plot B (3.1%), and Plot C (1.9%)—using a scientifically sound method.", "---", "### The Setup: Three Plots with Different Organic Matter Levels", "- Plot A: 2.4% organic matter by weight\n- Plot B: 3.1% organic matter by weight\n- Plot C: 1.9% organic matter by weight", "A 500-gram soil sample is taken from each plot, resulting in 1,500 grams (500g × 3) of composite material. To find the average organic matter content, a weighted average must be applied—because each plot contributes equally in volume despite differing organic matter concentrations.", "---", "### Step-by-Step Calculation", "1. Compute organic matter content per plot in grams:\n - Plot A: ( 500,\ ext{g} \ imes \frac{2.4}{100} = 12,\ ext{g} )\n - Plot B: ( 500,\ ext{g} \ imes \frac{3.1}{100} = 15.5,\ ext{g} )\n - Plot C: ( 500,\ ext{g} \ imes \frac{1.9}{100} = 9.5,\ ext{g} )", "2. Add the organic matter values:\n [ 12 + 15.5 + 9.5 = 37,\ ext{g} ]", "3. Divide total organic matter by total sample weight:\n [ \ ext{Composite organic matter%} = \frac{37}{1500} \ imes 100 = 2.466\overline{6} % ]", "---", "### Final Result", "The composite sample has approximately 2.47% organic matter by weight, reflecting the mean composition across the three plots.", "> ✅ Key Takeaway: This weighted average ensures that each plot’s contribution to the composite sample is proportionate—essential for accurate soil assessment in agronomic and environmental research.", "---", "### Why This Matters", "Accurate composite sampling supports better land management decisions, helps monitor soil health trends, and enables researchers to compare soil quality across varying practices or locations. Whether analyzing farmland, restoration sites, or carbon storage potential, understanding how to combine samples ensures reliable interpretation and actionable insights.", "---", "Keywords: soil organic matter, SOM analysis, compost sampling, soil science, composite soil sample, organic matter percentage, Plot A B C, soil health assessment.\nMeta Description: Learn how soil scientists calculate average organic matter content in a composite sample using three soil plots with different SOM levels—plot A (2.4%), B (3.1%), C (1.9%). Follow a step-by-step guide for accurate results.", "---", "By mastering these methods, scientists and land managers gain a powerful tool for sustainable soil monitoring and environmental stewardship."]
