Testing Soil Texture!

RHS Sustainable Agriculture Blog 10/9/15

This week during Sustainable Agriculture we were on the farm on Wednesday for a short thirty-five minutes, and again on Friday for a full block period. Our main focus of the week was working on our soil reports from our beds.

One of the most important things that we have been doing for the past week is testing the texture of our soil. The texture of soil is very important when it comes to farming and growing plants sustainably. Soil texture is determined by the percent composition of sand, silt and clay. Too much sand results in too much water percolating down into the ground, and too much clay results in too much water pooling up at the surface. The optimal type of soil is loam, which is a mixture of sand, silt and clay.

Last Friday we tested the texture of our soil using the first method: shake test / soil triangle. First we determined the percent composition of sand, clay, and silt in our soil, using the graduated cylinder with a soil solution from our bed. My group's soil sample was composed of 87.5% sand, 12.5% silt and 0% clay. This results in the soil type of loamy sand. In addition, we had 12 mL of organic matter in our soil.

On Wednesday, we used a second method (feel/squeeze) to determine the texture and type of our soil. First we grabbed a handful of soil from our bed and wet it with a little bit of water. First we had to determine if our soil could remain in a ball if we squeezed it. Our soil remained. Then we had to create ribbons out of our soil, which were short ribbons. Then we added water to determine if our soil was smooth or gritty. Ours was gritty. With all of the observations, we determined that our soil is sand loam. Ideally, our soil should have a little more clay and silt to have a soil texture.

-- Maddy Peng