The addition of pig slurry to soils of arid and semi-arid areas could result in an increase in salinity of those soils when considering the electrical conductivity of pig slurry. Experiments were done to verify the changes in soil salinity and the results showed that after manure application done at a rate of 400 m3/ha per year or more for a two year period presented a salinity risk as the electrical conductivity and soluble salt concentration had increased. An increase in the soil water-holding capacity, resulted in higher salinity risks. The water soluble potassium concentrations increased the most as potassium is present in manure and was applied at high rates. The composition of the clay fraction in the soil and its cation exchange capacity were determinant factor in the proportion of the potassium proportion in the soil.

The application of manure should be restricted to less than 200m3/ha in arid and semi-arid areas as the risks of salinity increase because of cation exchanges occurring with the sodium salts and manure components in the soil.