Gypsum is a common, naturally occurring sulfate mineral that is used agriculturally as a calcium source. It is a pretty versatile mineral. Commonly used for drywall, as a feed supplement for livestock, used in various medicinal applications, in art sculptures and much more: but for plants, it is an excellent source of calcium and sulphur. This mineral lowers the soils pH. So, if the soil is more alkaline and the plant prefers an acidic environment, gypsum will help achieve that. It helps with soil aeration and compaction issues and will occasionally help with turf pests. Regular use of gypsum is essential to the sustainability of most irrigated soils.
People commonly use gypsum to fix sodic soils and it also improves soil structure. Soils with high levels of exchangeable sodium (Na) and low levels of total salts are called sodic soils. These types of soils are poorly drained grow medium that get a crust or get hard layer. Also, they respond well to continued use of good irrigation water and irrigation methods. Â
Surprisingly, another one of gypsum’s amazing attributes is the ability to reduce aluminum toxicity which can sometimes came along with acidic soil, particularly in the subsoils. A more in-depth article on this can be found at Does gypsum improve soil health? (farmprogress.com)
- contains calcium 23% and sulphur 19%
- contains trace elements potassium and magnesium
- it reduces pH on alkaline soils
- assists with aeration and soil compaction
- improves water infiltration
- helps erosion and run off
Application
For trees, shrubs and flowers, add 2-4 cups spread around the plant base. In gardens, aprox. 50-1,00lbs per 1000 sq ft. Turf: New, 80-100lbs within the first 3 inches of soil prior to seeding. Heavy clay/compacted soil, apply up to 2 tons per acre to correct the soil. Compost: aprox. 4 cups per wheel barrel.
Extra Information
Info on sodic soils
 Managing Sodic Soils - 0.504 - Extension (colostate.edu)
http://www.gypsoil.com/soil-symposium/midwest-soil-improvement-symposium/2013-symposium