#208Gypsum application to soil
208⸱AConcept
- Regulates soil pH
- Improves soil structure
- Fosters deeper root growth
- Improves the coffee plant’s tolerance to drought
- Improves plant nutrition
- Increases the coffee yield
Gypsum (calcium sulfate, CaSO4) serves as a soil conditioner. The one-off application of a large quantity of gypsum to the soil benefits the soil’s structure and chemical composition, and therefore the health and resistance of the coffee plant.
Gypsum is used in coffee as a calcium and sulfur soil amendment, it ameliorates sodic soils and reduces aluminum toxicity in acidic soils, and improves the soil structure, which facilitates water infiltration. Therefore, in certain types of soil, especially oxisols and other soils that are sodic, highly acidic or suffering from high levels of aluminium, application of gypsum has been found to improve yields of coffee and many other crops.
Unlike applications of lime (calcium carbonate + varying quantities of calcium oxide, magnesium oxide and magnesium carbonate) which have the effect to reduce soil acidity, Gypsum is far more soluble than lime and can penetrate deeper into many soils. Once dissolved, gypsum is mobile in the soil, promoting the aggregation of soil particles. This process counteracts soil crusting, allowing air, water, and nutrients to penetrate deeper into the soil profile.
The above factors all make it easier for coffee roots to grow downwards and penetrate deeper into the soil where they find increased moisture, especially in the dry season, and thereby better resist severe droughts.
208⸱BTo be considered
The amount of gypsum for perennial crops, such as coffee plants, can be calculated using this formula:
Gypsum Requirement (NG) in kg/ha = 75 x (% clay)
It is important to consider that the percentage of clay will vary upon the soil type and can be obtained from the results of the physical soil analysis.
Alternatively, gypsum can be applied at a rate equivalent to up to 25% of the required lime application.
Applying high doses of gypsum can significantly increase calcium in the soil and consequently promote an imbalance with other cationic nutrients, such as magnesium or potassium. Therefore, it may be necessary to supplement the soil with additional nutrients. A soil analysis helps to keep an eye on the soil’s nutrient balance. Annual leaf analyses might be recommended to observe the nutritional status of the coffee plants.
Due to the above-mentioned aspects, it is recommended to start with a small number of trees, observe the results, and scale according to budget availability if the results are positive.
In years of good rainfall, it might seem that there are no differences between fields with and without gypsum; the main effect will be expressed in years of drought. It is not advisable to apply gypsum on sandy soils and with a risk of high rainfall.
Timing:
Large amounts of gypsum should be applied just once. They are generally applied during the preparation for planting until the third year, when the plants’ root system is developing
Supplementary doses can be applied at any stage of the crop's development, but it is recommended to do so at the end of the dry season and beginning of the rainy season, so it can start working quickly.
208⸱CImplementation
Materials
For 1 ha
208⸱1Application
If preparing a fresh coffee field for the plantation of new seedlings:
The gypsum can be mixed with other fertilizers and organic matter.
208⸱2
If applying to existing coffee plants in a field:
It is recommended to perform a soil analysis at a depth of 0-20 cm annually, the first being 6 months after planting, to check the effect on the soil’s nutrient balance and to make the necessary corrections to avoid the crop’s nutritional imbalances.
Every two years, also carry out an analysis at a depth of 20-40 cm.
208⸱DEconomic benefits
Higher coffee yield
The effects of this tool can lead to a higher coffee yield and therefore a higher income.
208⸱EGreen benefits
Better soil life
This tool helps improve soil life (microbes, earthworms, etc.). This plays a vital role in plant nutrition and contributes to a healthy ecosystem.
208⸱FComments