外文原文-饮用水处理剩余物可作为改善碱性土壤的改良剂.doc

1、外文资料Drinking water treatment residuals as an amendment to alkaline soils:Effects on the growth of corn and phosphorus extractability1*A. M. Mahdy; 1E. A. Elkhatib; 2N. O. Fathi1Department of Soil and Water, College of Agriculture, Alexandria University, Alexandria, Egypt2Salinity and Alkalinity Soil

2、s Research Laboratory, Ministry of Agriculture, Cairo, EgyptInt. J. Environ. Sci. Tech., 4 (4): 489-496, Autumn 2007ISSN: 1735-1472 IRSEN, CEERS, IAUReceived 22 April 2007; revised 22 June 2007; accepted 12 August 2007; available online 1 September 2007*Corresponding Author Email: amahdy73 Tel./Fax:

3、 +23 590 4684ABSTRACT: Drinking water treatment residuals (alum) are waste products of water purification that have potential for environmental remediation as a soil amendment and a potential plant growth medium. In this study, the influence of added Drinking water treatment residuals on the extract

4、ability and availability of phosphorus to plants; determination of the agronomic rate of alum to different agricultural soils and evaluation of the alum as ameliorating material for soil conditions and plant growth were investigated. In all studied soils, increasing drinking water treatment residual

5、s rate up to 30 g/kg significantly increased dry matter yield. Application of 10, 20 and 30 g/kg alum significantly increased plant P concentrations in the plant materials (shoots and roots) taken from clay, sandy and calcareous soils. Further increase in alum application rate has resulted in negati

6、ve significant impact on plants P concentration, especially in clay and calcareous soils, but in sandy soils the increase in phosphorusconcentration extended to 40 g/kg alum rate. Application of alum at rates up to 30 g/kg significantly increased available phosphorus concentrations of the three stud

7、ied soils. However, application of alum at a rate of 40 g/kg to clay and calcareous soils significantly decreased available phosphorus concentrations. Combined analyses of all soils and alum rates studied clearly indicated significant relationship between available phosphorus concentration and phosp

8、horus uptake (r = 0.87, P 0.001). Based on our experiment results, the rate of 30 g/kg is considered the best application rate of alum because of its positive effects on plant dry matter. Our study clearly demonstrates that alum has potential as a soil amendment to increase plant growth; however, mo

9、re research is needed to determine beneficial and / or detrimental aspects of this practice under field conditions.Key words: Water treatment residuals, phosphorus, extractability, plant, yieldINTRODUCTIONAluminum sulphate (alum) is a common chemical, fast and cost effective method for water purific

10、ation and improving water quality (Klapper, 1991; Barroin,1999). Hypolimnetic application of solid alum may reduce phosphorus levels, due to the ability of its hydroxide Al (OH) 3 to adsorb phosphorus at pH of 5.20-8.80 (Mortell and Motekaitis, 1989), remove colloidal organic matter and therefore in

11、crease water transparency (Francko and Heath, 1981; Jiang and Graham, 1998) even under anoxic conditions. Drinking water treatment residuals (DWTR) are waste products that have potential for environmental remediation as a soil amendment (Makris and Harris, 2005) and a potential plant growth medium (

12、Skene et al., 1995) because its high content of organic matter (0.85 to 6.5 %). Changes in soil water retention have been documented after DWTR land application. Bugbee and Frink (1985) and Rengasamy, et al., (1980) observed soil moisture retention and aeration improvements after DWTR additions. Onl

13、y a few studies have reported the consequences of land application of DWTR with respect to plant growth and environmental impact.Addition of DWTR at rates as low as 0.89 gk/gresulted in an increase in the growth of maize (Zea mays L.) (Bugbee and Frink, 1985). Tissue analysis of tomato shoots (Ellio

14、tt and Singer, 1988) and lettuce (Bugbee and Frink, 1985) grown in potting media amended with DWTR had significantly lower phosphorus levels. Our study objectives were to (i) evaluate the DWTR additions on plant growth; (ii) determine the influence of added DWTR on the extractability and availabilit

15、y of phosphorus to plants; and (iii) determine the agronomic rate of DWTR to different alkaline agricultural soils. MATERIALS AND METHODSCharacterization of soils and drinking watertreatment residuals (DWTR)Three soils with different properties (clay, sandy and calcareous) were selected for the stud

16、y and sampled (0-15 cm depth) from three different locations. Sub-samples of the air-dried soils were ground to pass a 2-mm sieve prior to the following chemical analysis:- pH and electrical conductivity (EC) as well as soluble cations and anions: soil-paste extract (Richard, 1954); organic matter: dichromate oxidation (Nelson and Sommers, 1982); cation exchange capacity (CEC): IM NaOAC (Rhoades, 1982); particle size: the hydrometer meth