Abstract

The effect of rice mill waste (RMW) in combination with or without NPK 15:15:15 on some physico-chemical properties of a Haplic Acrisol in Umudike, Southeastern Nigeria, was studied. The experiment comprised 10 treatments (20, 10, 5 and 2.5 t/ha RMW combined with 200 or 400 kg/ha NPK, 30 t/ha RMW alone, 400 kg/ha NPK alone and a control). They were laid in a randomized complete block design replicated 3 times. Data collected were subjected to analysis of varience. Results showed that relative to the control, application of RMW alone at 30 t/ha increased total porosity (P_t), saturated hydraulic conductivity (K_sat) and mean weight diameter (MWD) of water stable aggregates significantly by 41.1, 368.2 and 155.8%, respectively, and resulted in 20.9% significant decrease in bulk density (B_D). Improvements by other treatments in the physical parameters when compared to the control were not statistically significant except the application of 20 t RMW + 200 kg NPK/ha on B_D and P_t.  Similarly, a combination of 20 t/ha RMW with NPK at 200-400 kg/ha and application of 30 t/ha RMW had significant increase in percent organic matter (OM) over the control treatment, indicating the potentials of RMW in improving physico-chemical properties of poor soils.

Key words: Rice mill waste, porosity, hydraulic conductivity, aggregate stability.