Generally, the color of acid soil is dark, mostly dark brown, while the color of alkaline soil is white, yellow and other light colors. In some saline and alkaline areas, there is often a layer of white powdery alkaline substance on the soil surface.
Generally, the humus soil collected from mountains and rivers and gullies is mostly dark brown, relatively loose, fertile, with good permeability, so it is an ideal acid humus soil. Such as: pine needle humus, peat humus, etc.
Acid soil has loose texture, strong permeability; alkaline soil has hard texture, easy to agglomerate, poor permeability.
When digging flower soil in the field, we can observe the plants growing on the ground. Generally, the soil for Rhododendron, pine and fir plants is mostly acid soil, while the soil for Tamarix, millet and sorghum is mostly alkaline soil.
After the acid soil is watered, the infiltration is fast, without white bubble, and the water surface is muddy; after the alkaline soil is watered, the infiltration is slow, and the water surface is white bubble, white foam, sometimes there is a layer of white alkaline material around the flowerpot.
There is a kind of "soft" feeling in the hands of acid soil. When the hands are released, the soil is easy to disperse and not easy to agglomerate; when the hands of alkaline soil are released, it is easy to agglomerate but not disperse.
The pH test paper is used to measure the pH value of soil. The method is as follows: take some soil samples and soak them in cold boiled water, immerse some of the test paper in the soaking solution, take them out, observe the color change, and then compare the test paper with the colorimetric card. If the pH value is 7, the soil is neutral; if the pH value is less than 7, it is acid; if the pH value is more than 7, it is alkaline.
