Changes in Soil pH and Exchangeable Acidity of Selected Parent Materials as Influenced by Amendments in South East of Nigeria

Abstract

Soil chemical degradation caused by acidity is a serious constraint to food production in most parts of the Tropics. It was in the bid to proffer solution to this that the present study was con-ceived. Anincubation study was conducted at the laboratory of Soil Science and Meteorology De-partment of Michael Okpara University of Agriculture Umudike. The aim was to ascertain the ef-fect of amendments namely: Control (no amendment), Biochar, Ash, Lime, Biochar + Poultry Ma-nure, Ash + Poultry Manure and Lime + Poultry Manure, on soil pH and exchangeable acidity of Sandstone, Shale and Alluvium. The rate of application was 1.43 g for the sole amendments and 0.72 g each for the combined amendments to give an equivalent of 2 t/ha. They were applied to 100 g of the soil and replicated three times in a Completely Randomized Design. The incubation study lasted for eighty-four days, the pH and exchangeable acidity were determined at fourteen days intervals. The result obtained revealed that all the treatments increased the soil pH and de-creased the exchangeable acidity over the control. In all parent materials, applied Lime and Lime + Pm significantly (p < 0.05) gave the highest pH of 6.6, 6.9 and 7.2 for Shale, Sandstone and Allu-vium respectively on the 28 th day of incubation which, was the time, the maximum pH value was attained. Biochar and Biochar + Pm were considered the appropriate amendments because the pH values they gave were towards neutral, unlike that of Lime and Lime + Pm that were towards alka-line. It is recommended that field trial of this work is conducted.