Plant Problems With Brown Crust on Soil

Identifiication

• Sodic soils are those that contain too much sodium. They are typically alkaline and may be clay or sand. They drain poorly and are usually hard and full of dirt clods. Over time, the soils develop a black or brown crust. This crust is usually one of the later signs of sodic soils. By the time it appears, plants have already sustained damage.

Plant Growth

• Plant growth is hindered in sodic soils in several ways. The excess sodium ties up calcium in the soil, making it unavailable to plants. The plants may also be experiencing iron deficiencies. These deficiencies may cause poor growth and yellow leaves. Poor drainage may lead to root rot or general decline, while the hard, crusty surface inhibits germination.

Treatment

• If you suspect sodic soils, take a soil sample to a university extension office or commercial lab for a soil test. Tell the test administrator that you suspect sodic soil and ask for recommendations. In general, if your soil contains lime or gypsum, based on a soil test, you'll add sulfur to the soil to dissolve it. If the soil does not contain lime or gypsum, add calcium. Follow recommendations for amendment amounts carefully.

Plant Care

• While waiting for the results of a soil test, continue to water and fertilize plants. Till compost or peat moss into the soil. These amendments won't alter the amount of sodium in the soil, but they improve drainage and soil texture, which alleviates problems associated with sodic soil.