How to Compare Different Topsoils

Topsoil is the uppermost layer of soil and contains a high amount of organic matter and insect life. Farmers make caring for topsoil a priority because it is the layer of soil that plants obtain the majority of their nutrients, water and stability from. Topsoil is usually between 2 to 10 inches in depth.

1. Determine the organic matter content of the topsoil. Topsoil is often compared based on organic matter content. Organic matter provides the essential nutrients that plant life requires to survive. Soils with higher organic matter contents are almost always seen as favorable.


2. Measure the soil moisture. The moisture of topsoil refers to the amount of water stored in the soil's pore space. Ideal topsoils have around 50% of their pores filled with water. This statistic is usually sufficient to sustain crops. Too much water in the soil will inhibit plant life because there is less space available for gas exchanges.


3. Assess the relative porosity of the topsoil. Pore space in soil refers to the amount of space left between the soil aggregates, or clumps, of soil. Favorable topsoils contain enough pore space to store the water necessary for plant life and still allow space for gas exchanges.


4. Determine the composition of the soil. Soil composition refers to a combination of the constituents that the soil is composed of. This includes organic matter, minerals, water and gases. Fertile topsoils contain high amounts of organic matter and essential minerals.


5. Analyze the texture of the topsoil. Soil texture is based on the proportions of sand, silt and clay found in the soil. Soils that contain relatively high amounts of silt and clay are favorable because they retain nutrients and moisture better than sandy soils.


6. Measure microorganism activity in the soil. Microorganisms play several vital roles in the fertility of topsoil. They break down compounds to make nutrients such as nitrogen, phosphorous and sulfur available to plants. They also perform the important service of expediting the decomposition of organic matter, such as dead plants and animals. Common microorganisms found in soil are bacteria and fungi.