Thesis Abstract

<p>               <b>ABSTRACT&nbsp;</b></p><p>Heavy metals of livestock wastes (poultry manure) were studied. Heavy metals from two types of poultry manure (sawdust and straw bed) may represent a potential environmental risk for surface and groundwater. The test was made using a terrestrial microcosm, the Multi-Species Soil System (MS3) developed in the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA, National Institute for Agricultural and Food Research and Technology). The results of heavy metals in soils showed higher statistically significant differences (p ≤ 0.001) for Zn and Cd in straw and sawdust poultry manure amended soil. In the case of, Cd, Pb and Hg values were increased also for straw and sawdust poultry manure but did not show statistically significant differences. The presence of heavy metals, in the aerial parts of the wheat plant (Triticum aestivum), was studied and only Cu (sawdust poultry manure) and Hg (straw poultry manure) showed statistically significant differences (p ≤ 0.01 and p ≤ 0.05 respectively). The concentrations of Cd, Cu, Zn and Hg in earthworms showed significant differences (p ≤ 0.01, p ≤ 0.05 and p ≤ 0.001 respectively). Cu concentration showed significant differences (p ≤ 0.01) for straw poultry manure only. Finally, regarding the presence of metals in the leachates, only zinc, copper and nickel at 0 and 12 days showed statistically significant differences (p ≤ 0.0001) between control and the different types of poultry manure. For copper and nickel also differences were observed at 12 days. <br></p>

Thesis Overview

<p><b>1.0 INTRODUCTION</b></p><p><b>1.1 BACKGROUND STUDY&nbsp;</b></p><p>Excessive application of chemical fertilizer in agricultural soil had caused serious environmental problems, deterioration of soil physical structures, nutrients unbalance of soil, and water eutrophication. Livestock and poultry manure can be an alternative source of fertilizer in organic farming, where the use of anthropogenic chemicals is prohibited (Wong et al. 1999). The utilization of poultry manure as an organic fertilizer is essential for improving soil productivity and crop production (Cooperband et al. 2002, Dikinya 2010). However, several problems raised from applications of manure, including the salt toxicity of manure to plants (Meek 1974) and accumulation of trace metals in plants may pose a health risk when humans or livestock consume them (Diaz-Barrientos et al. 2003). So, further evaluation of application of manure, especially from intensive farming, should be given. However, it is not clear what the results are when these manures containing high concentrations of heavy metals are applied in agricultural soil, especially in a long term, because metal input through application of manures to soil will have a different behavior affecting soil chemistry and plant growth as well as metal uptake from the metals picked in soil as metal sulphate (Miyazawa et al. 2002, Walker et al. 2003). While the use of organic wastes as manure has been in practice for centuries world-wide (Straub 1997) and in recent times (López Masquera et al. 2008), there still exists a need to assess the potential impacts of poultry manure on soil chemical properties and leachates and in particular evaluating the critical application levels (Delgado et al. 2010). The multi-species- soil system (MS3), from two types of poultry manure (sawdust and straw bed), has also proved to be functional for assessing effects on earthworm, plants and microorganisms on an agricultural land (Delgado et al. 2012), and combined pollutants in contaminated sites (Fernández et al. 2005), MS3 can be used to monitor the mobility of metals in relation to biota (Alonso et al. 2006). The aim of this study was to apply the multispecies- soil system (MS3) for study the heavy metals on soil, organisms (plants and invertebrates), and leachates after the application of two types of poultry manure (sawdust or straw bed) on an agricultural land.&nbsp;</p><p><b>1.2 MATERIALS AND METHODS</b>&nbsp;</p><p>Multi-species-soil system The MS3 is an artificial assemblage of soil macroorganisms lying on homogeneous columns of sieved natural soil (Fernández et al. 2004, Boleas et al. 2005) that allows the assessment of its effects. In this experiment PVC cylinders (20 cm inner diameter and 30 cm high) covered by a fine nylon mesh at the bottom, to avoid soil loss, were used. The columns were installed in a climate room with a light-dark cycle of 16-8 h (1200 lux ±13 % coefficient of variation CV), air conditioning (21±1 ºC) and 55-60 % humidity. The MS3 columns were saturated with spring water. After that, 30 plant seeds and 10 invertebrates were introduced. During the exposure period, the MS3 was irrigated to simulate 1000 mm rainfall/year (Carbonell et al. 2009). Soil, poultry manure and organisms The soil used in this study was collected from an abandoned soil at “La Canaleja”, an experimental plant that belongs to INIA (35 km east of Madrid city) and was classified as a Typic Haploxeralf Calciorthid according to soil taxonomy criteria (Soil Survey Staff, 2003). A soil sample (0-30 cm) was air-dried, passed through a 2 mm sieve and analyzed following the standard soil test laboratory procedures of the Spanish Ministry of Agriculture, Fishing and Food (MAPA 1994). The main physicochemical characteristics of the soil were: pH, 8.3±0.45; EC (dS/m), 0.21±0.02; Kjeldahl nitrogen (%), 5.8±0.13; organic matter (%) 17±4.3; Ca (mg/kg), 4058±2.5; Mg extractable (mg/kg), 168±6.4; Na (mg/kg), 50±15.8; P (mg/kg), 1.7±0.13 and extractable K (mg/kg), 15±4.6. Poultry manure was supplied by Castilla-León farms located in the northeast of Spain. The physicochemical characterization of the poultry manure mixed with straw and sawdust shows a high organic matter content (%) (59.2±18.5 and 62.4±18.3 respectively), Kjeldahl nitrogen (%) (4.36±1.04 and 3.43±0.0 respectively). Neutral pH (7.32±0.35) for straw and alkali pH (8.27± 0.45) for sawdust poultry manure. <br></p><p><b>1.3 RESULTS AND DISCUSSION</b>&nbsp;</p><p>Metals analysis in soils The concentrations in soil for the seven selected metals in this experiment are summarized in Table II. The results were obtained at the end of the experimental period (day 21). The values for Cd, Pb and Hg showed an increase in straw poultry manure amended soil (0.049 mg/kg, 8.0 mg/kg and 0.059 mg/kgrespectively) with respect to the control values (0.039 mg/kg, 6.80 mg/kg and 0.05 mg/kg respectively) but were not statistical differences. The largest concentrations were observed for Cr and Zn and significant differences (p ≤ 0.001) for straw and sawdust poultry manure were showed. Regarding Cr, the results were similar for two types of poultry manure amended (7.20 and 7.30 mg/kg respectively) and finally, Zn was higher in straw than in sawdust poultry manure (25.0 and 21.0 mg/kg respectively). Increased concentrations of Cu and Zn in the surface horizons of soil receiving annual applications of PL (poultry litter) have been identified (Kingery et al. 1994). Copper and Zn concentrations in the surface of a soil profile that had received PL applications over 25 yr were higher than an unamended soil. Furthermore the results of this study suggest that Zn is fairly mobile in the profile. Using sequential extraction techniques, Cu was found to be mostly associated with the organic matter fraction in soils that had a 25 yr history of PL application (Han et al. 2000). Nicholson et al. 2003 studied the contribution of different animal types to selected total metal (Zn, Cu, Pb and Cd) inputs to agricultural land in livestock. Heavy metals inputs to agricultural soils in England and Wales were: 1858 t/yr of Zn (47 % cattle, 27% pigs and 26 % poultry), 643 t/yr of Cu (33 % cattle, 55 % pigs and 12 % poultry), 48 t/yr of Pb (71 % cattle, 13 % pigs and 16 % poultry) and 4.2 t/yr of Cd (64 % cattle, 10% pigs and 26% poultry). Also Lei et al. (2009), analyzed heavy metals inputs to agricultural soils in China where livestock manures accounted for approximately 55 %, 69 % and 51 % of the total Cd, Cu and Zn inputs, respectively. Study to evaluate the soil arsenic (As), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) enrichment that could result from the long term effect of poultry litter amendments and tillage practices on selected soil properties at the Alabama Agricultural Experiment Station, Belle Mina, AL, demonstrated that Cu and Zn did accumulate in the surface soil after 10 annual applications of poultry litter but not at phytotoxic&nbsp;</p><p>TABLE II. HEAVY METALS IN SOILS (mean ± standard deviation) Soils Treatments Heavy metals (mg/kg) Control Sawdust Poultry manure Straw Poultry manure p Zn 20.0a ± 0.9 21.0b ± 0.3 25.0b ± 0.1 0.0004 Cr 6.5a ± 0.6 7.2b ± 0.0 7.3b ± 0.0 0.0006 Cu 7.8a ± 1.4 6.0a ± 0.2 6.0a ± 0.1 &gt; 0.050 Ni 5.2a ± 0.1 5.0a ± 0.3 5.5a ± 0.1 &gt; 0.050 Cd 0.39a ± 0.08 0.40a ± 0.03 0.49a ± 0.07 &gt; 0.050 Pb 6.8a ± 0.9 7.5a ± 0.5 8.0a ± 1.3 &gt; 0.050 Hg 0.050a ± 0.006 0.051a ± 0.007 0.059a ± 0.018 &gt; 0.050 a,b Means with different superscripts are significantly different (P &lt; 0.050) LSD test. p = Probability values resulting from the analysis of variance <br></p>