[en] In order to find suitable varieties of tomato, pepper and cucumber for plastic greenhouse conditions in Ankara and ensure both higher yields and lower NO₃ leaching greenhouse experiments were conducted for three years. In the first year (2001) of the experiment four different varieties from each vegetable, namely, Tomato (Ecem F₁, 9920 F₁, 2116 F₁ and Yazg1 F₁), Cucumber (Hizir F₁ , Rapido, Hana, and Luna) and Pepper (1245 F₁, 730 F₁, Serademre 8 and 710 F₁) had been grown in the plastic greenhouse using drip irrigation-fertilization system. Yazg1 F₁ variety for tomato, Hizir F₁ variety for cucumber and Serademre 8 variety for pepper were chosen to be suitable varieties to grow in the plastic greenhouse conditions in Ankara. One access tube in each N₃ and N₀ treatment plots of tomato, cucumber and pepper in 2002 and 2003 experiments were installed for the soil moisture determinations at 30, 60 and 90 cm depths. Readings with the neutron probe were taken before planting and after harvest for the water consumption calculations using the water balance approach and the WUE was calculated on the basis of the ratio of dry matter weight to the amount of water consumed. Tensiometer and suction cups were installed at 15, 30, 45 and 60 cm depths only to N₁, N₂ and N₃ treatments plots of each vegetable in 2002 and 2003. Tensiometer readings were taken just before irrigation. Also, soil solution samples from suction cups were taken at final harvest and NO₃ determinations were done with RQFLEX nitrate test strips. Significantly higher yields and WUE values were obtained when the same amount of N fertilizer is applied through fertigation compared to the treatment where N fertilizer applied to the soil then drip irrigated. The nitrate concentrations of the soil solution increased as the N rates increased and no NO₃ had been found in the soil solution taken from 75 cm soil depth, indicating that no leaching of N fertilizer occurred beyond 75 cm soil depth. (author)

[en] In order to find suitable varieties of tomato, pepper and cucumber for plastic greenhouse conditions in Ankara and eventually to identify the best N fertilizer rate greenhouse experiments were conducted for two years. Yazgi F₁ variety for tomato, Hizir F₁ variety for cucumber and Serademre 8 variety for pepper were chosen to be the suitable varieties to grow in the plastic greenhouse conditions in Ankara. Five N treatments [N₀=0, N₁=150, N₂=300, and N₃=450 kg/ha; also, soil N application treatment (N_soil) equivalent to the fertigation treatment of 300 kg/ha was included for tomato and pepper, however N rates for cucumber was 131, 266 and 339 kg N/ha; N_soil being 266 kg N/ha] were investigated using ¹⁵N labeled urea fertilizer. Significantly higher marketable fresh fruit and total dry matter yields and N uptakes values were obtained from N₃ treatments for tomato and cucumber, but from N₂ treatment for pepper. Also, significantly higher yields, N uptakes and % NUE values were obtained when the same amount of N fertilizer is applied through fertigation compared to the treatment where N fertilizer applied to the soil then drip irrigated. (author)

No abstract available

[en] Full text: In order to find suitable varieties of tomato, pepper and cucumber for plastic greenhouse conditions in Ankara and ensure both higher yields and lower NO₃ leaching greenhouse experiments were conducted for three years. In the first year (2001) of the experiment four different varieties from each vegetable, namely, Tomato (Ecem F₁, 9920 F₁, 2116 F₁ and Yazg1 F₁), Cucumber (Hizir F₁ , Rapido, Hana, and Luna) and Pepper (1245 F₁, 730 F₁, Serademre 8 and 710 F₁) had been grown in the plastic greenhouse using drip irrigation-fertiligation system. Yazg1 F₁ variety for tomato, Hizir F₁ variety for cucumber and Serademre 8 variety for pepper were chosen to be suitable varieties to grow in the plastic greenhouse conditions in Ankara. One access tube in each N₃ and N₀ treatment plots of tomato, cucumber and pepper in 2002 and 2003 experiments were installed for the soil moisture determinations at 30, 60 and 90 cm depths. Readings with the neutron probe were taken before planting and after harvest for the water consumption calculations using the water balance approach and the WUE was calculated on the basis of the ratio of dry matter weight to the amount of water consumed. Tensiometer and suction cups were installed at 15, 30, 45 and 60 cm depths only to N₁, N₂ and N₃ treatments plots of each vegetable in 2002 and 2003. Tensiometer readings were taken just before irrigation. Also, soil solution samples from suction cups were taken at final harvest and NO₃ determinations were done with RQFLEX nitrate test strips. Significantly higher yields and WUE values were obtained when the same amount of N fertilizer is applied through fertigation compared to the treatment where N fertilizer applied to the soil then drip irrigated. The nitrate concentrations of the soil solution increased as the N rates increased and no NO₃ had been found in the soil solution taken from 75 cm soil depth, indicating that no leaching of N fertilizer occurred beyond 75 cm soil depth. Economical analysis showed that the highest profit would be made when tomato is grown instead of cucumber or pepper

[en] Full text: Nuclear techniques, which include the usage of radioactive and stable isotopes, had been used in soil fertility, plant nutrition, plant breeding, plant protection and food preservation research works after 1950s. Ultimately these nuclear techniques contributed greatly in increased plant production. In general, it is possible to separate the nuclear techniques used in soil fertility and plant nutrition into two groups. The first group is the use of radioactive and stable isotopes as a tracer in order to find out the optimum fertilization rate of plants precisely. The second group is the use of neutron probe in determining the soil moisture at different periods of the growing season and at various soil depths precisely without any difficulty. In research works where conventional techniques are used, it is not possible to identify how much of the nutrient taken up by the plant came from applied fertilizer or soil. However, when tracer techniques are used in research works it is possible to identify precisely which amount of the nutrient taken from fertilizer or from soil. Therefore, the nuclear techniques are very important in finding out which variety of fertilizer and how much of it must be used. The determination of the soil moisture is very important in finding the water needs of the plants for a good growth. Soil moisture contents changes often during the growth period, so it must be determined very frequently in order to determine the amount of irrigation that has to be done. Conventional soil moisture determination (gravimetric method) is very laborious especially when it has to be done frequently. However, by using neutron probe soil moisture determinations can be done very easily any time during the plant growth period

[en] A number of experiments were conducted to investigate the influence of different N rates applied through drip irrigation on the growth and N uptake by tomato, pepper, cucumber, melon and eggplant under greenhouse conditions. It was found that, for tomato, the % NUE was significantly increased by applying the N fertilizer through fertigation (53.9%) as compared to the soil application (34.0%) at 100 mg N/L. In general, any further increase of N fertilizer did not have an improving effect on the tomato yield. With pepper, the % NUE was significantly increased by applying the N fertilizer in the irrigation water (49.2%) as compared to the soil application (33.9%) at the same N level (140 mg N/L), being the optimum N rate under our greenhouse conditions. At a fertilization level of 100 mg N/L with fertigation, the % NUE was significantly increased as compared to the soil application. With respectively cucumber, melon and eggplant; the % NUE with fertigation was 63.4, 21.4 and 50.8%, while with soil application it was 34,0 11.0 and 18.8%. (author)

[en] In order to increase potato yields by drip irrigation and fertilization; and also to improve nitrogen and water use efficiencies of potato and eventually to obtain less nitrogen polluted surface and ground water, field experiments were carried out for three years at three different locations in Cappodocia Region of Turkey. Following treatments were investigated in field experiments: 1) N₀= Control, no nitrogen fertilizer application and drip irrigation; 2) N₁=300 kg N/ha fertilizer applied by means of fertilization, 3) N₂= 600 kg N/ha fertilizer applied by means of fertilization, 4) N₃=900 kg N/ha fertilizer applied by means of fertilization, 5) N₄=600 kg N/ha fertilizer applied on the soil surface and drip irrigation. Ammonium Sulphate was used as nitrogen fertilizer in all experiments.¹⁵N - labelled Ammonium Sulphate fertilizer were applied in isotope-sub plots for each treatment in order to determine the amount of nitrogen taken up by the plant, nitrogen use efficiency and the distribution of residual nitrogen at different depths in the soil profile. Soil water contents at different soil depths were determined by soil moisture neutron probe and water use efficiencies were calculated for each treatment. The results obtained show that a) by applying 44 % less water with drip irrigation equal amount of marketable tuber yields were obtained, b) nitrogen fertilizer was used more efficiently under drip irrigation compared to sprinkler irrigation which eventually indicated less leaching of nitrogen fertilizer

[en] In order to evaluate potato response to drip irrigation and N fertigation; and also to improve nitrogen and water use efficiencies of potato and eventually to obtain less nitrogen polluted surface and water, 10 field experiments were carried out at three different locations in Cappadocia Region of Turkey in 1997, 1998, 1999 and 2000 growing seasons. Nitrogen as ammonium sulphate ((NH₄)₂So₄), was supplied by drip irrigation water (fertigation) at rates of 0, 30, 60 and 90 kg N/da. Also, soil N application treatment equivalent to the fertigation treatment of 60kg N/da was included. These five treatments were investigated in a completely randomized block design with four replicants. Agria potato variety was used in all experiments and potato was planted in mid May and harvested at the end of October.''1''5N-labelled ammonium sulphate fertilizer were applied in isotope-sub plots within the macroplots for each treatment, in order to determine the amount of nitrogen taken up by the plant, nitrogen use efficiency and the distribution of residual nitrogen at different depths in the soil profile. Each year, during the growth period, total 12 irrigations were done and 50 mm of water was applied at each irrigation. At harvest, plant samples (tuber and leaf+vein) and soil samples were taken from each plot and N%, ''1''5N% atom excess (''1''5N% a.e.) and Ndff% determinations were done. Soil water contents at differrent soil depths were determined by soil moisture neutron probe at plantingand at harvest period so that water contents at different soil layers and water use efficiencies were calculated for each treatment. The results obtained showed that 3350 kg/da mean total marketable tuber yield was obtained with application of 600 mm irrigation water. Also,it was found that water did not move below 90 cm of soil layer in drip irrigation-fertigation system, which showed clearly that no nitrogen movement occured beyond 90 cm soil depth. Tuber yields and %Ndff increased when nitrogen is applied with drip irrigation-fertigation system in comparison to the application to the soil and then drip irrigation. At harvest, more nitrogen was accumulated at shallower depths with fertigation treatments