Two common features of degraded land are acidic and
saline soils. Soils become acidic (low pH) through the
leaching of bases by percolating water. Over time,
application of most ammonia-based fertilizers will also
lower pH. Lime, from limestone and dolomite, is frequently
applied to raise soil pH. By improving the conditions
for plant growth, liming increases nutrient
removal and enhances organic matter decomposition.
Concurrent application of lime and balanced nutrient
replenishment is usually necessary to ensure continued
long-term soil fertility.
Saline soils (high soluble salt content), sodic soils
(high sodium content), saline-sodic soils (high soluble
salt, high sodium), and high-lime soils are all
types of alkaline soils. Drainage and nutrient application
are usually sufficient to mitigate the effect of
high-lime soils. Saline, sodic, and saline-sodic soils
can usually be reclaimed over time through leaching.
Low soil permeability and large amendment
requirements make sodic soil reclamation a slow
and expensive process.