Dark brown or black color in soil indicates that the soil has a high organic matter content. Wet soil will appear darker than dry soil. However, the presence of water also affects soil color by affecting the oxidation rate. Soil that has a high water content will have less air in the soil, specifically less oxygen.Click to see full answer. In this way, why is Regur soil black?Black soil is dye to high content of organic matter or rich with iron and magnesium minerals and metals . It makes the color of soil dark sometimes black.Additionally, why is my soil turning yellow? The most common reason for a plant’s leaves turning yellow is moisture stress due to either under-watering or over-watering. If your soil feels dry and you haven’t been watering that often, you can assume you may be under-watering. Similarly, you may ask, can dirt be black? Why Soil Turns Black According to Cornell University, the darker the soil, the higher the level of organic matter. High levels of iron or magnesium can also cause soil to turn black. Similarly, clay-heavy soils are often more darkly colored lower in the soil structure than sand-heavy soils.Why is my soil Green?The green material on the soil surface could be moss or algae. If the layer appears as a somewhat thickened matt, it could be moss. If the layer is thin, then it may be algae. Both moss and algae grow in soil that is always moist.