a) If the silty clay loam soil profile is 1 meter deep, how much plant available water (cm) can potentially be held in the upper meter of soil?
b) If the silty clay loam profile is 40 inches deep, how many inches of plant available water can potentially be held in the upper 40 inches of soil?
To determine the plant available water in the given soil profiles, we need to understand the concept of Available Water Holding Capacity (AWHC) and its calculation. AWHC represents the amount of water that can be stored in the soil and is available for plants to use. It is measured in units of depth, such as centimeters or inches.
The AWHC can vary depending on the soil type and its characteristic properties. In your case, the soil profile is described as a silty clay loam. Soil texture influences the water holding capacity because different textures have varying amounts of pore spaces that can hold water.
To estimate the AWHC for the given soil profiles:
a) For a silty clay loam soil profile that is 1 meter deep:
1. Determine the texture class of silty clay loam using a soil texture triangle or laboratory analysis.
2. Consult a soil water characteristic curve or database specific to your soil texture.
3. Look up or calculate the volumetric water content at field capacity and at wilting point for a silty clay loam soil.
4. Subtract the volumetric water content at wilting point from the volumetric water content at field capacity.
5. Multiply the difference obtained in step 4 by the depth of the soil profile (1 meter) to convert it into centimeters.
b) For a silty clay loam soil profile that is 40 inches deep:
1. Convert the depth from inches to centimeters by multiplying by a conversion factor (2.54 cm/inch).
2. Follow the same steps as in Part a to calculate the plant available water in centimeters.
Please note that the specific values needed to calculate AWHC will vary based on the soil texture and region. It is recommended to refer to soil surveys, local agricultural extension services, or consult soil experts for accurate information related to your specific soil profile and region.