Title: THE RELATIONSHIP OF EXCHANGE ACIDITY AND EXCHANGEABLE ALUMINUM IN LIMED AND UNLIMED PROFILE SAMPLES OF SOIL FROM WESTERN OREGON TO THE YIELD AND CHEMICAL COMPOSITION OF ALFALFA Abstract approved

Acidity distribution within any given soil profile is dependent on mineralogical make-up of the parent material as well as environ mental conditions prevalent during the weathering history of the soil. An experiment was designed to study the distribution pattern of ex change acidity, exchangeable aluminum, exchangeable manganese and pH of six acid soils of Western Oregon. IN KC1 extracts of four depths of each soil were obtained and the levels of the parameters mentioned above were measured. It was found that various soil serie; had different acidity distribution patterns within their profiles. Also, a highly significant linear correlation was observed between exchange acidity and exchangeable aluminum of each soil. Liming acid soils raises pH of the soil extract and improves its fertility status. The rise in pH is due to neutralization of acid groups or acid-producing species present in various forms and on various sites in the soil system. One group of these acid producin