Fig. 1. Changes of sorption of NH₄⁺ in Kennebec and Haynie soils with time. The two soils were exposed to the liquid swine waste (closed symbols) and the (NH₄)₂SO₄ solutions (open symbols) at a soil/solution ratio of 1:10. The measured pH values of the liquid swine waste–soil mixture were 8.0 and 8.2 for Kennebec and Haynie soils, respectively. The pHs of the (NH₄)₂SO₄–soil mixtures were adjusted to the same values as that of the corresponding waste-soil mixtures. Both solutions initially contained 495 mg NH₄⁺–N L^–1.