Browsing by Author "Sönmez, F"

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Lettuce Grown on Calcareous Soils Benefit From Sewage Sludge
(Taylor & Francis As, 2006) Sönmez, F; Bozkurt, MA
The present study aimed to evaluate the effects of sewage sludge, manure and humic acid applications on soil properties and element concentrations of soil and plants. As a field experiment, lettuce was grown on soil amended with 0, 20, 40 and 80 t ha(-1) of sewage sludge or manure. Humic acid was applied on sewage sludge amended plots as 250 kg ha(-1). Addition of sewage sludge and manure increased lettuce yield, head circle, head height and leaf number and N, P, K and Mg levels to same extent. Leaf Cd concentration increased in sludge treated plots more than manure treated plots. Sewage sludge and manure applications increased organic matter, electrical conductivity, total N, available P, exchangeable K, total Cu, Ni and AB-DTPA ( ammonium bicarbonate-diethylenetriaminepentaacetic acid) extractable Mn, Cu and Cd concentrations of topsoil. Extractable Fe, Cr and Zn and total Cd, Cr and Zn increased in soil with added sludge. Soil pH was unaffected by either sludge or manure applications. Lettuce leaf concentrations of Cd from the plots treated with humic acid were lower than those not treated with humic acid. Sludge together with humic acid application significantly increased soil available P, and impeded the increase of the soil AB-DTPA extractable Zn concentration. It may be concluded that sewage sludge can be an alternative to manure to enrich organic matter, and rectify N, P, Fe and Zn deficiencies with high pH and calcareous soils. Also, humic substances can be used, to a limited extent, for controlling the availability of sludge-borne heavy metals.
Effects of Humic Acid Doses and Aplication Times on the Plant Growth, Nutrient and Heavy Metal Contents of Lettuce Grown on Sewage Sludge-Applied Soils
(Parlar Scientific Publications (p S P), 2006) Tüfenkçi, S; Türkmen, Ö; Sönmez, F; Erdinç, Ç; Sensoy, S
Effects of increasing doses of humic acid (HA), applied in different periods, on the plant growth, nutrient and heavy metal contents of lettuce grown on sewage sludge-applied soils were investigated. A constant dose of 20% sewage sludge (SS) was added to experimental soil placed in pots. Various doses of HA (0, 500, 1000, and 2000 mg kg(-1)) were applied to the pots for different time periods (0, 30, 60, and 90 days before seedling transplantation). Increasing doses of HA significantly affected the plant and neck diameter, the plant height, the number of leaves, but not the plant weight. Application times of HA significantly influenced all plant growth parameters mentioned above. Moreover, there were significant effects of the interaction of HA dose and application time on the diameters, heights, and weights of lettuce plants. There were significant effects of increasing doses of HA on the N, P, K, Ca, Mg, Fe, Zn, and Cd contents of lettuce plants. Their Cd, Cr, and Co contents decreased with increasing HA doses. Also, significant differences in N, P, K; Mn, Cd, and Ni contents could be observed for various application times of HA. Moreover, the Mn content of lettuce was affected by the time and dose interaction. As a result, the application of HA had positive impacts on the plant growth and nutrient contents of lettuce, and increasing doses of HA reduced the heavy metal contents, such as Cd, Cr, and Co, in lettuce plants. The early application of HA for lettuce, with a short growing period, had more beneficial effects for the plant growth and nutrient content.