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conservation practices. Soils are an important natural resource. They are a medium for 111 plant growth, a regulator for water supply, a recycler of raw materials, a habitat for soil 112 organisms, an engineering medium and an environmental interface. Overall, soils are a 113 very complex matrix including physical and living components that lead to ever-changing 114 compositions. 115 Variability in soils can be problematic. The physical and living components of soil 116 change with depth of the soil, leading to soil horizons in a single soil profile that have 117 different characteristics. With the different characteristics in mind, care must be 118 exercised when collecting samples to avoid mixing soil types. These horizons can have 119 different pH, organic content and clay minerals. Soils also vary seasonally and over time. 120 A collected soil sample is considered a catch sample and represents a snapshot in time of 121 that soil. Outside of the soil profile, soils change with distance such that 2 soil samples 122 collected only a few feet apart can have very different characteristics. When collecting 123 soil samples, reviewing soil maps and preparing to analyze the sample shortly after 124 collection is recommended in order to confirm the characteristics desired for the 125 experimental purpose. If planning on combining sub-samples of collected soil, field 126 texture methods and field soil pH kits are helpful in establishing similar characteristics 127 between the sub-samples. 131 can be divided into 3 main mineral groups: sand, silt and clay. Clay is the most active 132 component of soil, having the smallest size and therefore the largest surface area. Any 133 128 129 130 6.1 Soil Texture Soil consists of organic and non-organic components. The non-organic components

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