Managing Soil Salinity
Soil salinity, which affects a considerable part of cultivatable lands, is one of the factors that limit production of many agronomic and horticultural crops. Various methods have been used for a long time to reduce the impacts of soil salinity stress, but the definitive effectiveness of some of them has not been completely proved. Use of agricultural gypsum and sulfur compounds is among these methods. Agricultural gypsum is applied as an inexpensive and available technique for coping with soil salinity stress.
The results show that soil at the depth of 15-30 cm has stronger alkaline pH and higher electrical conductivity compared to the upper soil, and applying agricultural gypsum improves these two indices considerably. In addition, available sodium at this depth decreases substantially by applying gypsum or sulfur compounds and reaches a more suitable threshold with lower salinity stress levels. Soils are considered among the very important factors in plant growth. Each soil must contain the suitable nutrients for plant growth.
In many cases, soils lack these nutrients and hence they must be applied to soil. However, sometimes there are materials and salts in soil that are not only useless for plants but also harm them. Saline and sodic soils are among the soils that need to be amended to have the appropriate quality for plant growth. Calcareous soils are one of soil types. Agricultural gypsum can have a substantial role in hydraulic structures and in building them.
Soils can be considered calcareous when their calcium carbonate content exceeds 10%. When the pH of cell sap is higher than 7, especially in fruit trees, nutrients are deposited in the trunk and branches of trees and in the stems and branches of agronomic plants. Calcareous soils, excessive soil salinity, and presence of calcium bicarbonate are all factors that prepare the ground for the deposition of these nutrients. One of the techniques in amending calcareous soils is to use soil and water together with agricultural gypsum.