SOIL 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.

CHAPTER ONE

1.0       INTRODUCTION

The low productivity of maize and soybean  in Africa is largely  attributed to low and decreasing soil fertility due to many factors, such as soil acidity, soil erosion, continuous cropping and inadequate sustainable soil fertility management (Berga et al., 2001; Van Straaten, 2002; Kiiya et al., 2006; Crawford et al., 2008). The soil acidity affects the fertility of soils through nutrient deficiencies (P, Ca and Mg) and the presence of phytotoxic nutrients such as soluble aluminum and manganese. Acid soils can stunt seed germination, and root development due to inhibition of uptake of nutrients by plants. The application of cement waste materials to agricultural land can increase pH of soils, reduce fluctuation of soil pH, reduce plant and root stress; hence the cement wastes can successfully be used as a liming agent in acidic soils (PENNSTATE, 2004).

Application of  cement by-products: Cement Kiln Dust (CKD) and Agricultural Lime (AGL)  reduces Al and Mn toxicity, improves soil pH, Ca, Mg and increases both P uptake in high P fixing soil and plant rooting system ( Asadu and Agada, 2008). Use of the cement kiln dust is a potential option for soils’ sustainable management among the other options for improving soil acidity, restoring soil health and fertility.

The globally growing demand of cement results in towering collection of wastes from cement  plants.  The  disposal  of  this  fine  dust  material  is  very  difficult  and  poses environmental threat. To overcome this problem, research is being executed in different parts of the world to find out economical and efficient ways of using cement dust in various applications in agriculture, soil enhancement, base pavement stabilization, waste water treatment and water remediation.

The general trend all over the world is the re-utilization of cement waste products in useful application to prevent or at least reduce environmental pollution and keep the balance of the environment (Darweesh, 2001). In order to minimize the undesirable environmental impacts and conservation, many researches have been conducted to investigate beneficial use of cement kiln dust (CKD) and other cement wastes as raw material, fertilizer, construction material and for improving soil properties (El-Awady and Sam, 1997). These wastes (AGL and CKD) in practical terms vary markedly from plant to plant in chemical, mineralogical and physical composition, depending upon the   feed raw   material, type of kiln operation, dust collection facilities and the fuel used (Klemm, 1993).

The potential of these cement wastes to improve soil properties has long been recognized in developed countries (Johnson, 1986) but their effect in Nigerian tropical soils, where organic matter plays a more vital role in soil productivity have not been extensively studied. It is therefore important to explore these wastes (AGL, CKD, and WWS) as alternative sources of soil fertility management to mineral fertilizer in a subtropical Africa setting like Nigeria. Proving the suitability and utilization of these wastes for agricultural production will not only provide a cheap source of fertilizer to farmers but also a ready means of ridding the factory environs of the menace of the waste.

Therefore the general objective of this study was to evaluate the suitability of these wastes (CKD, AGL, and WWS) from a cement plant in improving soil fertility and increasing soybean and maize production in soils of Yandev, North central Nigeria.

The specific objectives of the study were to:

1)  evaluate the effects of the three wastes, viz: cement kiln dust, agricultural lime and waste water sludge on soil physico-chemical properties;

2)  determine the agronomic yield of soybean (Glycine max) and maize (Zea May L) at different rates  of waste application  and

3)  compare the soil properties and performance of test crops from soils amended with wastes and recommended mineral fertilizer.

Related Project Topics :