The general effect of swine effuent application on soil pH is a decrease in pH with increasing application rates. In 1977 and 1978, large differences were found between treatments but large variations among replicates of the same treatment resulted in a few significant differences. The decline in pH with increasing application rate is consistent with the loss of Ca2+ and Mg2+ from the surface layer due to effluent additions of Na+, K+ and NH4+. The pH decline and the loss of Ca2+ and Mg2+ stress the need for periodic additions of dolomitic limestone.
"Swine Lagoon Effluent Applied to 'Coastal Bermudagrass: II. Effects on Soil"
King, Westerman, Cummings, Overcash and Burns
J. Environ Qual., Vol. 14, no. 1, 1985