In a laboratory study, the potential use of the organic wastes, poultry manure (PM), compost (CM), sawdust (SD), brewers’ spent grains (BG), rice (Oryza sativa) shavings (RS), gmelina (Gmelina arborea) leaves (ML), and cashew (Anarcadium occidentale) leaves (CL), to improve the structure and water retention properties of an ultisol was evaluated. These wastes were applied at the rates of 5 and 10%. The relative improvement in any physical property considered was computed as 100 ( where Pt and Pc are the amended and control treatments respectively.Additions of the wastes at both 5 and 10% decreased soil bulk density but increased total porosity, macroporosity, saturated hydraulic conductivity, water retention at different potentials as well as the organic matter contents of the soils. A ranking of performance of the wastes, taking into consideration all physical properties evaluated, showed the order RS > SD > ML > CM > CL > BG > PM.There were positive and significant correlations between organic matter and water retained at the −0·01, −0·033 and −0·05 M Pa potentials, total and readily-available water, saturated hydraulic conductivity, total and macroporosity, but a negative correlation with bulk density. This indicates that increments in organic matter due to additions of these wastes may partially explain improvements in these physical properties. Choice of any of these wastes will be dictated by the uses to which the land will be put as well as availability.
Biological Wastes 01/1989; 28(1):1-13. DOI:10.1016/0269-7483(89)90044-X