Alkaline soil is a type of soil with a high pH level, typically above 7, and a soil structure that can hinder the growth of many garden plants. Alkaline soil is also referred to as "sweet soil" and usually contains a great deal of sodium, calcium, and magnesium. The causes of soil alkalinity can be natural or man-made. The natural cause is the presence of soil minerals producing sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) upon weathering. Soil can also become more alkaline if it is watered with hard water that contains lime. Alkaline soils are difficult to take into agricultural production. Due to the low infiltration capacity, rainwater stagnates on the soil easily and, in dry periods, cultivation is hardly possible without copious irrigated water and good drainage.
To fix alkaline soil, one of the best ways is to increase acidity in soil by adding sulfur. Adding 1 to 3 ounces (28-85 g.) of ground rock sulfur per 1 square yard (0.8 sq. m.) of soil will lower pH levels. If the soil is sandy or has a lot of clay, less should be used, and it needs to be mixed in very well before using. Organic matter such as peat moss, composted wood chips, and sawdust can also be added to bring down the pH. However, it is important to note that altering soil pH is not always practical or possible, and it may be better to look for plants that are more efficient at taking up micronutrients from alkaline soils.
