Effect of organic amendment on properties and nutrient loss of soils of selected parent material

Abstract

Soils of Southeastern Nigeria like those of other humid tropical countries are prone to leaching due to high rainfall resulting in low fertility, nutrient status, and crop yield. Evaluating the effects of selected organic amendments on retention of nutrients in soils is of major concern and formed the purpose of the study. Soil samples were collected from Asu River Group, (ARG), Bende Ameki Group (BAG), Coastal Plain Sand (CPS) and Falsebedded Sand Stone (FBS) which were the four respective parent materials studied. Three replicates of 10 kg of prepared samples from each parent material were bagged and thereafter applied with 10 tons ha-1 each of poultry (PD) and goat droppings (PD, GD). The thoroughly mixed combinations laid in a completely randomized design (CRD) were allowed to blend for three months after which, samples were collected from each bag and analyzed. The remaining amended soils were subjected to a rainfall simulation which enabled the collection of sediment yield which was also analyzed to determine the nutrients in them. Generated soil data were analyzed with analyses of variance (ANOVA). Means were separated using the least significant difference (LSD) at 5% probability level. The result showed that soil organic carbon increased from 15.80 – 17.70, 6.90 - 14.20, 7.10 – 13.90 and 11.39 - 17.50 gkg-1 in ARG, BAG, CPS and FBS respectively before and after amendment and later decreased to 10.8, 11.30, 6.70, and 8.30 g kg-1 in the sediment yield following simulation. Similarly, there were significant losses of about 23.52, 60.85; 60.00 and 47.20 % of total nitrogen to detached soils in the respective lithologies. Total nitrogen and available phosphorus losses in the soils followed the order: CPS > FBS > BAG > ARG and FBS > CPS > BAG > ARG respectively.