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Depth Matters: Unveiling the Impact of Soil Sampling Depth on Test Results

The soil data which includes various parameters collected from 6 unique soil samples at two different depths: 6 inches and 12 inches. The samples are from Abohar, Punjab, and were all collected on January 10, 2024. The collection was supervised by Saumya from Ekosight.

The dataset contains a wide range of soil properties, such as pH, Electric Conductivity (EC), and levels of various nutrients including Nitrogen (N), Phosphorus (P), Potassium (K), Sulfur (S), Zinc (Zn), Iron (Fe), Manganese (Mn), and Copper (Cu). Each parameter is accompanied by an interpretation, categorizing the levels as low, medium, or high based on standard ranges.


Punjab Abohar 12 Soil samples Test - Google Sheets
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Our analysis reveals some interesting patterns and variations in soil properties. Here's a summary of the key findings:

  • Nitrogen (N): The average nitrogen levels are slightly higher in the 6-inch depth samples (163.91) compared to the 12-inch depth samples (161.49), suggesting that nitrogen might be more available in the upper layers of the soil.

  • Phosphorus (P): A significant difference is observed in phosphorus levels, with the 6-inch samples having much higher average values (78.18) than the 12-inch samples (44.82). This indicates that phosphorus is more abundant in the surface soil.

  • Potassium (K): Potassium levels are somewhat similar between the two depths, with the 6-inch samples having a slightly lower average (383.16) compared to the 12-inch samples (412.29).

  • Organic Carbon (OC): Organic carbon shows higher average values in the 6-inch samples (0.22) compared to the 12-inch samples (0.18), reflecting perhaps more organic matter presence at shallower depths.

  • Sulfur (S): The sulfur content is significantly higher in the 12-inch samples (27.49) compared to the 6-inch samples (18.43), suggesting sulfur might be leaching to lower depths.

  • Calcium (Ca) and Magnesium (Mg): Calcium and magnesium both show higher averages in the 6-inch depth samples (Ca: 581.33, Mg: 187.9) compared to the 12-inch depth samples (Ca: 528, Mg: 216.8), indicating a possible depletion or different distribution pattern as depth increases.

  • pH and Electric Conductivity (EC): The pH levels are almost identical between the two depths, suggesting a stable acidic-alkaline balance across the soil profile. However, electric conductivity, which indicates salinity, is slightly higher on average in the 12-inch samples (0.19) than in the 6-inch samples (0.15).

  • Micronutrients (Mn, Zn, Fe, Cu): Manganese and iron levels are higher in the 12-inch samples (Mn: 0.013, Fe: 0.057) than in the 6-inch samples (Mn: 0.025, Fe: 0.005), while zinc and copper show a mixed pattern. Zinc is significantly higher in the 6-inch samples (1.1) compared to the 12-inch samples (0.22), and copper is also higher in the 6-inch samples (0.68) compared to the 12-inch samples (0.48).


The depth at which soil samples are collected plays a critical role in understanding soil health and fertility, as clearly demonstrated by the variations observed between the 6-inch and 12-inch depth samples in the provided data. This difference in soil properties with depth has significant implications for agricultural practices, environmental management, and the understanding of soil ecosystems. Here are some key points highlighting the importance of considering soil sample depth:

1. Nutrient Availability and Root Zone:

The availability of essential nutrients like nitrogen, phosphorus, and potassium varies with depth. Most plant roots, especially those of agricultural crops, are concentrated in the topsoil layer, typically within the first few inches. Therefore, nutrient levels in the topsoil are critical for plant growth and development. The report indicates higher levels of phosphorus and organic carbon in the 6-inch samples, which is beneficial for the initial growth stages of crops that rely heavily on surface soil nutrients.

2. Soil Health and Structure:

Soil health, including its structure, organic matter content, and microbial activity, often varies significantly with depth. The top layer is usually richer in organic matter due to the decomposition of plant and animal residues. This is supported by the data, which shows higher organic carbon content at the 6-inch depth. A healthy topsoil structure supports water infiltration and retention, which are crucial for crop resilience against drought.

3. Leaching and Nutrient Distribution:

Leaching can cause nutrients and minerals to move downwards through the soil profile. This is evident in the sulfur content being higher in the 12-inch samples in the report, suggesting that some nutrients may be more available at lower depths, depending on the soil type and environmental conditions. Understanding this movement is essential for managing nutrient applications to ensure they are accessible to plant roots and to prevent groundwater contamination.

4. Soil Salinity and pH:

Soil salinity and pH can affect plant growth, nutrient availability, and microbial activity in the soil. The similar pH levels observed at both depths in the report suggest a uniform soil acidity-alkalinity balance, which is good for maintaining a stable growing environment. However, variations in electric conductivity indicate differences in salinity, which can have implications for crop selection and irrigation practices.

5. Micronutrients and Trace Elements:

Micronutrients, though required in smaller amounts, are essential for plant health. The variation in micronutrient levels, such as zinc and copper, between the two depths as seen in the report, highlights the need for depth-specific soil testing to ensure adequate micronutrient management.

6. Environmental and Climatic Impacts:

Environmental factors such as rainfall, temperature, and wind can affect the soil's surface layer more than its deeper layers. Soil sampling at different depths can provide insights into how these factors influence soil composition and structure over time, aiding in the development of more effective soil conservation and management strategies.

7. Tailored Agricultural Practices:

Understanding the variation in soil properties with depth allows for more precise and efficient agricultural practices, including tillage, irrigation, and fertilization. It enables farmers to apply inputs where they are most needed, reducing waste and environmental impact while maximizing crop yields.

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