Bülent Okur

THE EFFECT OF NITROGEN SOURCES ON YIELD AND QUALITY OF SALAD ROCKET GROWN IN DIFFERENT MONTHS OF THE YEAR

The effects of months of the year and nitrogen (N) sources on salad rocket (Eruca sativa Mill.) yield, quality, and nitrate accumulation was investigated during the years 2002 and 2003. In both years, seeds were sown on the first day of April, May, June, July, August and September. Three different nitrogen sources were used: farmyard (cattle) manure (100 tonnes·ha−1), calcium nitrate [Ca(NO3)2]-15.5% N (150 kg N·ha−1) and ammonium sulfate [(NH4)2SO4)]-21% N (150 kg N·ha−1). Yield, leaf color, dry matter, vitamin C and total glucosinolate content and nitrate accumulation was assessed. Growing months affected all the assessed parameters significantly both years, with the exception of hue angle in 2003, whereas nitrogen source only influenced yield and nitrate accumulation in 2003. In both years the highest yield was obtained in April, but vitamin C and total glucosinolate contents were higher during summer months, and leaves were slightly darker colored. Chemical fertilizers increased the yield compared to farmyard manure; however, they also increased nitrate accumulation slightly, without any significant difference between them. Nitrate accumulation never exceeded 300 mg kg−1 fresh weight (FW), which is well below the acceptable daily intake of 3.7 mg nitrate per kg−1 bodyweight set by European Commissions Scientific Committee on Food.

Effect of manure doses and growth media on the productivity and mineral composition of rocket leaves (eruca sativa)

Rocket (Eruca sativa) is a member of the Brassicaceae family. It is found endemic in most Mediterranean countries and in Northern and Eastern Europe. According to 1996 records, the annual production of rocket in Turkey was nearly 1100 t green fresh leaves which are mostly used as appetisers with traditional Turkish foods like “pide” (Turkish pizza) or “Kisir” (Turkish wheat meal) or to prepare fresh salads. Rocket was also believed to have aphrodisiac properties. It is used in traditional pharmacopoeia for many different purposes. In this study, three different levels of farmyard manure (4 t da−1; 8 t da−1; 12 t da−1) were applied to experimental soil; experimental soil mixed with pumice and perlite. Five kg da−1 N; 2 kg da−1 P2O5; 1.5 kg da−1 K2O were applied to growth media as basic fertilisation.

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.

The effects of saline irrigation water by drip irrigation on salt distribution in soil

Depending on the increase in the salt amount in irrigation water in many arid and semi-arid regions of the world, salinity problems in agricultural soils appears and agricultural production is inhibited by excessive salt concentrations. This type of salinity occurs in topographical lowlands near the sea where intrusion of seawater to the aquifer is inevitable [1]. The reason why salinity is high in the areas near the sea, or in areas gained from the sea, is due to seawater intrusion. The salt composition of these soils is the same with that of the seawater [2]. The salinity of the seawater is accepted as approximately 0.35 %. The concentrations of main ions in seawater are 19.35 me L-1 Cl-, 10.752 me L-1 Na+, 2.701 me L-1 SO4 =, 1.295 me L-1 Mg+2 and 0.39 me L-1K+ [3]. Approximately 70% of the world’s population lives near, or at, the seaside. The rise in the population and the settlement in these areas increase the agricultural and industrial activities, hence a pressure on water sources takes place. The greatest effect of this pressure is on the change in the quality of underground water sources [4]. Various factors affect the salinity of underground water sources. The most important reason for the salinity in the aquifers at the seaside is the seawater intrusion [5].

Farklı Tuz Dozlarının ve Mandarin Anaçlarının Topraktaki Tuz Dağılımı Üzerine Etkileri

An ongoing field trial was established in 1996 at the experimental site of Ege University Faculty of Agriculture Dept. Horticulture. In the study, two different rootstocks (Poncirus trifoliata and Troyer citrange) were budded onto Satsuma mandarins (cv. Owari) which are irrigated with 5 different levels 0.65 (fresh water-I0), 2.00 (I1); 3.50 (I2); 5.00 (I3) and 6.50 (I4) dS m of saline water by drip irrigation. The aim of the study was to examine the horizontal and vertical distribution of salt in the soil at two different dates of irrigation season, mid and end. In the mid term samples, salt accumulation was in the horizontal direction on rows and decreased with the increased distance from the drippers. On the other hand, in the samples taken at the end of the season salt accumulation was towards between rows with an increasing trend. Soil at the rooting zone of Poncirus trifoliata rootstock contained less Na and Cl ions than the Troyer citrange plots.