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THE INFLUENCE OF SEWAGE SLUDGE APPLICATION ON SOME CHEMICAL
PROPERTIES OF A AND B HORIZONS IN A RED MEDITERRANEAN SOIL
N. Chouliaras1, C. Tsadilas2, K. Tsitsias1, and D. Dimoyiannis2
1: Technological Educational Institution, Larissa, Greece, 2: National Agricultural Research Foundation
(N.A.R.F.), Institute of Soil Classification and Mapping, Larissa, Greece
INTRODUCTION
The correction of soil acidity in cultivated lands is necessary for red soils, characterized by acid A horizons (Soltner, 1982). All these treatments for the improvement of A horizon, have an effect on B horizon, intentionally or not. Among the materials used to correct soil acidity are sewage sludges (Hue, 1992). In the present work, the correction of soil acidity was tried to an A horizon of a red Mediterranean soil, in an incubation experiment using sewage sludge. The influence of this application on some chemical properties of A horizon, is compared with the effects induced by the same application on B horizon of the same red soil.
MATERIALS AND METHODS
Ιn a red Mediterranean soil (Typic Rhodoxeralf) selected from Almiros region of Magnesia, urban sludge (biological cleaning of Larissa) was applied in both A and B horizons. The pH, organic matter content, cation exchange capacity of the A horizon were 4.82, 1.5%, and 7 cmol(+)/Kg, respectively. The values of the previous characteristics of the B horizon were pH 7.34, organic matter content 0.8% and cation exchange capacity 20 cmol(+)/Kg. The rates of sludge applied were 0, 1.8, 3.6, and 5.4 g of air dried sludge per 100 g soil. The treatments were prepared in triplicate and the samples were maintained in a temperature 28o for 9 weeks. All samples were saturated at 2/3 of water holding capacity, during the first 3 and the last 3 weeks, while they were maintained dry for the rest of the time.
During the incubation period and every third week, soil samples were taken and analysed for NH4+-N and NO3--N content. At the end of the incubation period, soil samples were analysed for NH4+-N, NO3--N, electrical conductivity, pH, organic matter, inorganic-P, organic-P, P-Olsen, exchangeable forms of K, Ca, Mg and available forms of Fe, Zn, Mn, and Cu extracted by DTPA. Similar observations for the influence of sewage sludge application on the above mentioned soil properties were reported and by other workers (Soon et al. 1978, Higgings 1983, Kuo et al. 1985).
RESULTS AND DISCUSSION
Some results of this experiment are quoted in Table-1.
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extracted by DTPA. On the contrary the exchangeable K was not significantly affected by the sludge application, while Fe and Mn were significantly reduced. P-Olsen, Fe, and Mn extracted by DTPA were strongly negatively correlated with pH, though Cu was positively correlated with pH. On the other hand, P-Olsen and Zn extracted by DTPA were well correlated with organic matter content. In general the influence of sewage sludge was more intense on the A horizon.
Table-1: Effect of sewage sludge on soil properties.
A* B
E0 E1 E2 E3 E0 E1 E2 E3 pH (1:5) susp. 4,82d** 5,49c 5,91c 6,90b 7,34ab 7,94a 7,92a 7,87a P-Olsen, μg/g 39d 54c 62b 69a 7g 16f 23e 37d Kex, me/100g 0,58a 0.55a 0,568a 0,58a 0,58a 0.55a 0,568a 0,58a
Fe μg/g *** Zn μg/g Mn μg/g Cu μg/g
10,7a 8,8b 7,6b 8,3b 1,4c 7,2b 10,1a 10,4 299,2a 123,3b 98,3bc 82,6cd 2,1d 2,7bcd 3, 1bc 3,2bc
5,0c 3,6c 4,2c 4,8c 0,0c 6,8b 9,9a 9,9a 41,7e 35,9e 43,5e 57,9de 2,6cd 3,3bc 3,4b 4,3a
* A, B: Soil horizons, E: sewage sludge rates, ** Mean separation by Tukey's multiple range test at the 0,05
level, *** Extracted by DTPA
REFERENCES
Higgins, A.J. 1984. Land application of sewage sludge with regard to cropping systems and pollution
potential. J. Environ. Qual. 13:441-448.
Hue, N.V. 1992. Correcting soil acidity of a highly weathered ultisol with chicken manure and sewage
sludge. Commun. Soil Sci. Plant Anal., 23(3&4):241-264.
Kuo, S., Jellum, E.J., and Baker, S.A. 1985. Effects of soil type, liming, and sludge application on zinc
and cadmium availability to Swiss chard. Soil Sci. 139(2):122-130.
Soltner, D. (1982): Les bases de la production végétale. tome 2, 2e Ed. Sc. et Techn. Agr. 312 p.
Soon, Y.K., Bates, T.E., Beauchamp, E.G., and Moyer, J.R. 1978. Land application of chemically
