Soil Science Productivity Enhancement and Agronomic Potential of Cement Waste Products in Gboko, Benue State, Nigeria

Abstract

The effect of waste products from a cement plant on soil physical and chemical properties with agronomic potentials, using two test crops, were assessed on a Loamy Sand Alfisols of Yandev in Benue state of Nigeria. In this study cement waste products: Cement Kiln Dust (CKD), Agricultural Lime (AGL) and Waste Water Sludge (WWS) were used as treatments at two rates of 4 t ha-1 and 8 t ha-1. The two rates of mineral fertilizer used for maize were NPK 15:15:15 (0.30 t ha-1 and 0.60 t ha-1) for first application, Urea (0.10 t ha-1 and 0.20 t ha-1) for second application). Similarly, the two rates of mineral fertilizer recommended for soybean were: SSP (0.20 t ha-1 and 0.40 t ha-1) and MOP (0.03 t ha-1 and 0.07 t ha-1) rates for first application, Urea (0.02 t ha-1 and 0.04 t ha-1) for second application rates. The study was a field trial with two application rates of cement waste products, waste water sludge and mineral fertilizer. The trial was carried out during the 2014 and 2015 planting season using maize (Zea mays L, variety: TZSER- Y) and soybean (Glycine max, variety: TGX1448-2E) as test crops. The two crop varieties were all obtained from National Cereal Research Institute (NCRI) substation, Yandev. The experimental layout was a Randomized Complete Block Design (RCBD) with the treatments replicated three times. Result of the study showed that these cement waste products (CKD, AGL) and waste water sludge (WWS) significantly (p < 0.05) improved the top soil physical and chemical properties (0-20 cm) than those of the sub-soil (20-40 cm) properties. The improvement in soil physical properties was evidenced by reduced bulk density, increased total porosity and hydraulic conductivity. Similarly, the soil chemical properties: soil pH and exchangeable bases (K, Ca, CEC and BS), increased significantly (p < 0.05) following the application of cement wastes (CKD and AGL). The application of these wastes also produced significant changes in a few of the subsoil chemical properties such as soil pH, exchangeable Ca and Base saturation. The improved soil condition provided by the cement wastes (AGL and CKD) must have enhanced the agronomic parameters of test crops observed in the study. The waste water sludge (WWS) however improved some of the soil physical properties (soil porosity and hydraulic conductivity) significantly (p < 0.05), but failed to improve the soil chemical properties and yield of test crops significantly (p < 0.05). There was significant (p < 0.05) increase in some of the agronomic maize parameters such as plant height, leaf area index (LAI), stem girth, cob girth, cob length and yield of maize (tha-1) in AGL, CKD, and FET amended plots. Similarly, CKD and FET significantly (p < 0.05) enhanced some of the soybean agronomic parameters (soybean height, leave area index, pods per plant, pod per plot and soybean yield). Result of the study showed that application of cement wastes (CKD and AGL) at 4 t ha-1 and 8 t ha-1 improved soil properties and crop yield as much as mineral fertilizer, although the application rate of 8 t ha-1 of wastes (CKD, AGL and WWS) and two rates of mineral fertilizer improved more soil properties and yield of the test crops (maize and soybean) than the 4 t ha-1 when compared.