Nutrition
Gypsum supplies 23% calcium and 18% sulphate sulphur in a plant available form.
As a fertiliser, gypsum can be used to increase and maintain calcium and sulphur levels in the soil. Gypsum is often applied to orchard and tree crops prior to flowering and fruit set to supply additional calcium at this time. Gypsum can be used as a cost effective sulphate sulphur fertiliser for application in early crop establishment. Gypsum has little or no effect on soil pH.
Plants need Calcium
Luxury levels of calcium is required for a wide range of horticultural and arable crops. Fruit with a higher-than-average calcium status are less likely to suffer physiological and postharvest storage problems. Calcium is a structural part of every plant cell wall and cell membrane. It also affects the activity of many plant enzymes. Calcium is taken up passively in the transpiration flow and moves in the xylem sap to the leaves and, to a lesser extent, fruit.
Plants need Sulphur
Sulphur is necessary for amino acids, proteins, vitamins, the synthesis of some plant hormones as well as being part of the photosynthesis process. It is essential for the production of healthy, green leafy material. Without adequate sulphur, plants suffer from chlorosis (lack of chlorophyll). Like calcium, sulphur is not mobile within plant tissues, so a continuous supply is needed for growing plants.
New Zealand soils are commonly low in sulphur. Traditionally superphosphate has been applied to bring up levels of sulphur. Superphosphate applications raise the concentration of phosphorus in the soil which may cause leaching of phosphorus into waterways. Gypsum allows the application of sulphur only without any phosphorus additions.
Lime versus Gypsum
Lime is effective at raising the pH of an acid soil and is used as a source of calcium in the form of calcium carbonate.
An application of lime tends to raise soil pH and is used to correct soil pH. Lime has low water solubility so it is relatively immobile in the soil. It must react chemically with other soil components before it can gradually migrate downwards and penetrate the subsoil layers. This takes a very long time. Liming may reduce infiltration of surface-water runoff, reducing soil water re-charge after rain.
Gypsum is partially water soluble with more soil mobility, delivering calcium down through the soil profile below the cultivation area. Gypsum offers it's benefits more rapidly and at greater soil depth than lime. Gypsum has little effect on soil pH. Gypsum can be applied on its own or blended with lime in a ratio of 40:60 or a 50:50 blend.
Gypsum Product Range
Claybreaker™ Finely ground gypsum for use on clay soils and home garden. Pack sizes include 8kg and 25Kg bags.
Soil Life® Finely ground gypsum for use in horticultural and agricultural situations. Pack sizes include 25 Kg bags and 1000 Kg sling bags.
Natural Screened Gypsum Screened gypsum for use in horticultural and agricultural situations. Available in 25Kg bags, 1000Kg singbags, bulk truck and trailer deliveries.
Where to buy Gypsum
View all distributors here.