Neutralizing Soil Acidity under Bermudagrass Sod

Abstract

AbstractThe effectiveness of surface‐applied lime in preventing subsoil acidification from residually acid N sources used on Coastal bermudagrass (Cynodon dactylon L. Pers.) was influenced by (i) soil type, (ii) lime rate, (iii) N source, and (iv) N rate. Lime applied at a rate equivalent to acidity of the N source maintained both pH and exchangeable bases in a loamy sand but not in a clay loam soil. Lime applied at three times the N fertilizer equivalent acidity was more effective in correcting subsoil acidity than were lower rates, and the effect was more pronounced in the coarse‐ than in the fine‐textured soil.Calcium gluconate was highly effective in increasing subsoil pH and exchangeable base level under Coastal bermudagrass but caused an undesirable fungal bloom. Surface‐applied NaNO3 was effective in correcting subsoil acidity in both a coarse‐ and a fine‐textured soil without accumulation of Na, and the effect was relatively uniform throughout the depth of profile sampled (45 cm). Calcium nitrate was also effective in increasing subsoil pH and exchangeable Ca in medium textured soil to a depth of 45 cm, with less pronounced effects down to 75 cm. Residual basicity of Ca(NO3)2, as measured by increase in exchangeable Ca in the soil profile, ranged from 1.7 to 2.5 kg CaCO3 per kg N, depending upon rate of application.