M. Rüştü Karaman

Effect of Different Irrigation Programs with Nitrogen Fertilizer Application on Nitrogen Use Efficiency and Fruit Quality in Tomato

A lysimeter study was conducted based on completely randomized block design at the Agricultural Research Institute of Tokat in 1996–98. The lysimeters were filled with soils taken from AP, C1 and C2 horizons of the Kazova plain in Tokat-Turkey. Three seedlings of tomato variety H-2274 were transplanted to each lysimeter. Nitrogen fertilizer at the rates of 0 and 140 kg N.ha−1 was side dressed in two split applications. The lysimeters were irrigated based on programs C 0.75, 1.00, 1.25 and 1.50, C referring to class A-Pan evaporation coefficients. The maximum yield was obtained with irrigation programs C 0.75 and C 1.00 together with 140 kg N.ha−1 treatment. Significant negative correlations (r = −0.66 for 1996 and r = −0.70 for 1997) were found between Class A pan coefficients (C) and fertilizer-N-use. In general, N-uptake decreased with utilization of C 1.00, C 1.25 and C 1.50 programs possibly due to the maximum N-leaching losses occured with these practices. Considering fruit quality, the water soluble dry matter, protein and nitrate contents were decreased, however, total acidity and ascorbic acid were increased with increasing irrigation practices. The results further revealed that the concentrations of NO 3 − and NO 2 − in drainage water were closely related to leaching which were considerably higher with programs C 1.25 and C 1.50.

15N investigation of nitrogen released from tobacco-waste to be utilized by maize crop

The 15N study aimed to estimate the portion of nitrogen released from tobacco-waste to be utilized by maize crop. Tobacco-waste at the levels of 0, 2, 4, 6 and 8 g pot−1 and (15NH4)2SO4 as nitrogen fertilizer labelled with 5 at.% exc. at the levels of 0, 4, 8, 12 and 16 mg N pot−1 together with a basal dressing of some nutrients were added to pots with Pioneer maize variety. After the harvest, dry matter yield was recorded and 15N determinations and calculations were made. Tobacco-waste had a positive effect on the growth and on the nitrogen uptake of maize crop. Increasing the rates of tobacco-waste increased the dry matter yield of maize crop from 4.64 g pot−1 (at control) to 7.22 g pot−1 (at the tobacco-waste treatment of 8 g pot−1). The values of 15N in the plant derived from nitrogenous fertilizer also increased with increasing nitrogen fertilizer levels, whereas they decreased from 0.427 % to 0.249 % with increasing tobacco-waste treatments from 0 to 8 g pot−1, respectively. The average values of per cent nitrogen derived from nitrogenous fertilizer (Ndff) varied from 4.32 % to 7.95 % at the rates of 4–16 mg N pot−1, respec-tively. However, Ndff decreased from 8.54 % to 4.99 % with increasing tobacco-waste treatments from 0 to 8 g pot−1, respectively. Per cent nitrogen derived from tobacco-waste (Ndft) increased from 21.8 % to 38.5 % with increasing tobacco-waste treatments from 2 to 8 g pot−1, respectively. The results have revealed that 15N tracer technique was confidently used for the investigation of nitrogen levels released from tobacco-waste as organic waste to be utilized by maize crop.

Assessing the subsequent effect of nitrogen released from tobacco-waste on maize crop using a 15N isotope technique

The investigation of the residual effect of nitrogen (N) released from tobacco-waste (TW) using isotope techniques will provide valuable data for sustainable organic farming. For this aim, a pot experiment was conducted using the 15N isotope technique. The experiment was based on a completely randomised design with four replications and was conducted on a calcareous ustochrepts soil. TW at levels of 0, 10, 20, 30 and 40 t ha−1 and N fertiliser as (NH4)2SO4 at levels of 0, 20, 40, 60 and 80 kg N ha−1 were used for the Bezostaja-1 wheat variety. Concerning mineral N fertilisation with 20 and 80 kg N ha−1, additional treatments with 15N-labelled (NH4)2SO2 (10 at.% exc.) have been applied. Following harvesting wheat plants, the Pioneer 3377 maize variety was used to see the residual effect of TW. After harvesting, dry matter yields were recorded and total N concentrations were determined. 15N determinations and calculations were also made for 15N treatments separately. TW had a significant residual effect on the growth of corn plant under the pot condition. Increasing rates of TW significantly increased the dry matter yield of corn plant following wheat from 3.31 t ha−1 (at control) to 7.89 t ha−1 (at the TW treatment of 40 t ha−1). The 15N values derived from the 15N fertiliser decreased with increasing TW application. The average values of N derived from N fertiliser (Ndff) varied from 2.14 to 3.09% at the rates of 20 and 80 kg N ha−1, respectively. However, N derived from TW (Ndftw) significantly increased from 16.93 to 24.59% (at 20 kg N ha−1), and it also increased from 23.06 to 28.15% (at 80 kg N ha−1) with increasing TW applications from 20 to 40 t ha−1, respectively.

Computer Based Geostatistical Strategies in Assessing of Spatial Variability of Agricultural Phosphorus on a Sugarbeet Field

Evaluating the computer based geostatiscial methods will eliminate the unequal soil phosphorus variability on agricultural fields. These methods may commonly be useable for simulation of spatial variability of agricultural phosphorus on these areas. It will be valuable for balanced phosphorus consumption by crops and reduced environmental pollution. In this study, topsoil (0-20 cm) and subsoil (20-40 cm) samples based on 20 X 20 m grids were collected from the plots under the sugarbeet plants. Plant samples were also collected from the same plots. The soil and plant samples were prepared for analysis. The data concerning with phosphorus levels were analyzed through Kriging interpolations, which are the computer based geostatistical methods. To achieve cross-validation, distribution percentages were formed by using all Kriging methods. As a result of cross validations, the best optimal method was found to be Simple Kriging interpolation method for each data group (Ordinary RMS, plus or minus 6.38, Simple RMS, plus or minus 5.98 Universal RMS, plus or minus 6.41). By using this method, semivariogram models were tested, and exponential semivariogram model was found as the most suitable model for the experimental data group. Soil and plant phosphorus distribution faces were adequately determined by using selected simple Kriging interpolation method and suitable semivariogram model. These distribution faces were processed by software 3D analyst modul to enable three dimensional mapping.

Assesment of Periodical Nitrogen Use of Tomato Using a Computer Program

In this study, conducted with lysimeters, we wanted to test the performance of LEACHN computer model to simulate the nitrogen uptake of plants at experimental sites. Nitrogen fertilizer at the rates of 0, 80, 160 and 240 kg N.ha−1 was side dressed in two split applications, first half as ammonium sulphate and the other half as ammonium nitrate. The lysimeters were irrigated based on program C 1.00, C referring to class A-Pan evaporation coefficients. Yield and N-use efficiency increased with increasing nitrogen rates up to 160 kg N.ha −1, however, they decreased drastically under 240 kg N.ha −1. The results also releaved that some fruit qualities were significantly affected by N-rates. The ability of LEACHN model to simulate crop-N-use was tested using Model parameters for experimental site. Significant correlations (r = 0.95 for 1996 and r = 0.94 for 1997) were found between measured and simulated values for the plant N-uptake, suggesting that the LEACHN model can be confidently used to estimate the crop-N consumption.

Değişik Formlarda Uygulanan Azotlu Gübrelerin Domates Bitkisinin (Lycopersicon Esculentum L.) Demir, Bakır, Çinko Ve Mangan Kapsamına Etkisi

The main object of this study is to investigate the effect of different nitrogenous fertilizers on the micronutrient content of tomato plant.This research was laid out on the Land of Agricultural Faculty during the year 1995. The experiment was planned by using split plot design with two factors and three replications. In this experiment, H-2274 tomato variety was used. Nitrogen sources as ammonium nitrate, ammonium sulphate, calcium ammonium nitrate, urea and potassium nitrate were used at 0, 4, 8, 16, 32 kg N/da rates. In addition, 10 kg P205/da as TSP and 5 kg K20/da as K2S04 were applied for normal growth of the tomato plants. Total 13 harvests were taken during the year. In addition, leaf and fruit samples were taken at the time of maximum yield. According to the result of this study, Fe, Cu, Zn and Mn contents of tomato were varied with nitrogen form and rates. Especially, nitrate forms decreased the micronutrient content of tomato plant.