Sezai Delibacak

Fertility status, trace elements and heavy metal pollution of agricultural land irrigated from the Gediz River

The effect of the Gediz River, polluted by industrial and domestic wastes, on fertility status and trace elements and heavy metal pollution of agricultural land irrigated from this river was investigated. For this purpose, soil samples were collected in August 1998 between the source of the Gediz River (Murat Mountain) and its mouth (Aegean Sea). Soil samples were collected from 12 different sites along the length of the river basin from 0-30 cm depth. The soils were slightly alkaline, with no salt problem and were poor in organic matter. Total N and available P, K, Mg, Fe and Zn levels were low or average, whereas available Ca, Na, Cu, Mn were present at good and sufficient levels. Thirty three per cent of soils had available B and S of soils had total B levels above the phytotoxic lower boundary. Because of the geographical/geological structure, soil samples from the Gediz source (Sample Site 1) had high amounts of total Fe, Zn, Mn, B, Cd, Ni, Cr and Co. At the second sampling site, total Ni content was also higher than is acceptable according to the national standards set. In addition, in some soil samples the amount of total Cd was above the lower phytotoxic boundary value.

Review of spatial variations in water quality in the Gediz River

The Gediz River is one of the most important and main water source for the Gediz Basin of the Aegean region and Turkey. In this study, 18 water samples were collected from the source to the end of the river. Change in water quality, some trace elements and heavy metal contents of the Gediz River were determined. Analysis of the Fe, Cu, Mn, Zn, Pb, Cr, Co, Cd and Ni showed that the quantity of Fe in the eighth sample, taken before the meeting point of the Alasehir tributary-Gediz River and the quantity of Cr in the eighth sample were above the critical level. Overall, the study indicated that the quality of the water of the Gediz River deteriorated (along the river) from the source to the end. It was also determined that the N/P ratio diminished from the source to the end which is an indicator of domestic pollution. To preserve the soils and plants of the Gediz Basin, the Gediz River and its tributaries should be protected from garbage and effluents.

Effects of Tobacco Waste and Farmyard Manure on Soil Properties and Yield of Lettuce (Lactuca sativa L. var. capitata)

The aim of this study is to compare the effects of composted tobacco waste (CTW) with farmyard manure (FYM) on soil physical and chemical properties and yield of lettuce. This research was performed in the experimental fields of the Agriculture Facultys research farm at Ege University in Menemen, Izmir, Turkey in 2005 and 2006. Tobacco wastes gathered from the cigarette industry were composted and applied to lettuce (Lactuca sativa L. var. capitata) with manure. Mineral fertilizers or pesticides were not applied in the experiment. The treatments were (1) control, (2) 12.5 t ha–1 FYM + 37.5 t ha–1 CTW, (3) 25 t ha–1 FYM + 25 t ha–1 CTW, (4) 50 t ha–1 FYM, (5) 50 t ha–1 CTW, and (6) 37.5 t ha–1 FYM + 12.5 t ha–1 CTW. During the experiment, soil samples were taken three times in two different periods (I, 7 September 2005; II, 11 November 2005; and III, 14 April 2006). The effects of CTW and FYM on soil physical and chemical properties and the yield were investigated. All application rates increased bulk density, field capacity, available water content, and structure stability index of soil when compared with the control. In addition, similar effects were also determined for chemical properties of soil (pH, lime content, organic matter, total soluble salt, and cation exchange capacity). Increasing rates of nitrogen, phosphorus, and potassium provided a rise in the yield. Maximum lettuce yield was 102.7 t ha–1 at the plots where 50 t ha–1 CTW was applied. The results show that CTW can be used as an effective soil conditioner.