ABSTRACT

 A study was conducted at Michael Okpara University of Agriculture, Urnudike to determine the effect of carbon and nitrogen content of the organic waste combinations on soil chemical and structural indices. The amendments were Sawdust (SD), Poultry manure (PM) and admixture of Sawdust and poultry manure, applied at the rates of Ot/ha, 2t/ha, 4t/ha and 8t/ha. The treatments were replicated three times. The physico-chemical properties analysed for include Soil pH, Organic carbon, total nitrogen, aggregate stability, moisture content, bulk density and porosity, Exchangeable acidity, TEB, ECEC and % base saturation. Data collected were subjected to analysis of variance using 4 x 3 factorial in a RCBD; significant means were detected using F — LSD at 5% probability level. Results indicate that the organic amendments significantly (P < 0.05) improved the micro-aggregate stability, bulk density and total porosity of the amended soils. Similar trend was observed for soil pH, while exchangeable acidity decreased relative with application of amendments. There were improvements in organic matter, TEB, % BS and ECEC of the amended soils. The linear correlation between organic carbon and structural stability indices show that increase in organic carbon result to a decrease in structural stability (DR, CFI, CDI, ASC) indices but an increase in MWD <0.06mm at micro-level.