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Mehmet KEÇECİ 1, Aydın GÜNEŞ 2 1 Soil and Fertiliser Research Institute, Ankara, Turkey 2 Agriculture Faculty of Ankara Dep of Soil Science, Ankara, Turkey Abstract 316 soil samples were collected from the greenhouses in the Mediterranean region of Turkey and analysed for texture, pH, total salt, lime, organic matter, iron, zinc, copper and manganese contents. The results of the survey revealed that the greenhouse soils in general are of sandy loam texture, neutral reaction, slightly saline, high organic matter content, and very high lime content, high in iron zinc and cupper contents, low in Manganese contents. Tomatoes, green pepper, cucumber and egg plants were the plants that were grown in the surveyed green houses. Introduction Soil is the very important part of the agricultural system and it is impossible to achieve high yields without knowing the physical and chemical properties of the soils. If the plant nutrients are not supplied in adequate amounts as fertilisers, they will restrict the yields resulting in economical losses for the farmers and the country. The properties of the soils, the crop type and the conditions of the growth medium will determine the amount of plant nutrient to be applied. Yield is severely affected when a nutrient is deficient and when the deficiency is corrected very rapid plant growth occurs. Soil analysis values are very valuable for successful fertiliser recommendations and management. Agricultural production under field conditions can not satisfy the market demand of the rapid growing world population. More intensified and controlled systems are looked for achieving higher yields. Green houses are now being continuously used for achieving higher yields under controlled conditions. Day by day green house production is increasing its share in the agricultural system. An important part of the national vegetable production is by means of greenhouses and the share of greenhouse production is continuously increasing. Farmers who transfer from field type production to greenhouse type production are not very familiar with the necessary soil plant nutrient practices. The soils are either polluted by over fertilisation which lead to loss of soil quality or less plant nutrients are applied then the required which lead to reduced yields. The research is conducted in the Mediterranean region, which is one of the most important green house production areas of Turkey in order to monitor the soil qualities for achieving better yields in the future. Material and Method 316 Soil samples representing different green houses in the region are collected from 0- 25 cm soil depth. The collected soil samples are analysed for texture, pH, lime, organic matter, salt content, and plant available Fe, Cu, Zn and Mn content. The Trace elements are determined by A.A.S fallowing an extraction with DTPA as described by Lindsay and Norwell (1969) . Texture is determined according to Bouyoucos (1951), Organic matter according to Walkley - Black method as described in Chapman and Pratt ( 1961). The lime content was determined according to Scheibler method as described by Tüzüner (1990) and the salt determination was according to Tüzüner (1990) also. Tomatoes, green pepper, cucumber and eggplants were the plants that were grown in the surveyed greenhouses. The analysis values for texture, pH, lime, organic matter and salt content were classified according to Ülgen and Yurtsever (1988), the analysis values for iron, and cupper are classified according to the critical values set by Lindsay and Norwell, the analysis values for zinc and manganese are classified according to FAO (1990). The critical values of adequacy for iron, zinc, cupper and manganese were 4.5 ppm, 0.7 ppm, 0.2 ppm and 14 ppm respectively. Results and Conclusion The texture of the majority of the greenhouse soils are sandy-loam. The sandy loam soils constitute 73.74% of the soils. The detailed texture distribution of the soils is presented in figure 1. The texture of the soils in general does not create any problem for high yields.  The majority of the greenhouse soils are slightly saline. The slightly saline soils constitute 46.83 % of the whole greenhouse soils. The salt level of the soils varied between % 0.050 and 1.790. The average salt level was % 0.376. The salt level of the green house soils may negatively effect the crop yields in near future. The detailed salt distributions of the soils are presented in figure 2.  The reaction of the majority of the green-house soils are neutral. The neutral reaction soils constitute 82.91 % of the soils in the region. The pH of the greenhouse soils varied between 5.32 and 8.16. The average pH value was 7.17. The pH of the greenhouse soils may become a problem on long term so, special attention must be paid for the use of physiological acidic type of fertilizers. The detailed pH distribution of the all greenhouse soils is presented in figure 3.  The lime content of the majority of the soils are of very high lime content. The very high lime content soils constitute the 30.07 % of the whole greenhouse soils in the region. The lime content of the soils varied between 0.30 and 47.70 % and the average lime content was % 15.79. High lime content of the soils indicate a possible iron and zinc deficiency, and phosphorus fixation problems. Care must be paid to trace element nutrition. The detailed lime distribution of the soils is presented in figure 4.  The organic matter content of the majority of the soils are of high organic matter content. The high organic matter content soils constitute the 28.16 % of the whole greenhouse soils in the region. The organic matter content of the soils varied between 0.26 and 7.59 % and the average organic matter content was 3.26%. Almost half of the greenhouse soils are not adequate in organic matter content. Attention must be paid for increasing the organic matter content of the green house soils. The detailed organic matter content distribution of the soils is presented in figure 5.  The majority of the green house soils are of high iron content. The high iron content soils constitute the 90.82 % of the whole greenhouse soils in the region. The iron content of the soils varied between 1.58 and 92.54 ppm and the average iron content was 9.49 ppm. It seems that there will be no signs of iron deficiency problems but still care must be paid for signs of iron deficiency because of high lime contents. The detailed iron content distribution of the soils is presented in figure 6. The majority of the soils are of high Zinc content. The high Zinc content soils constitute the 41.78 % of the whole greenhouse soils in the region.  The zinc content of the soils varied between 0.04 and 44.79 ppm and the average zinc value was 6.28 ppm. Although zinc status of the soils seems adequate in most of the soils attention must be paid for zinc deficiency because of the high pH values. The detailed zinc content distribution of the soils is presented in fig. 7.  The majority of the soils are of low manganese content. The low manganese content soils constitute the 48.10 % of the whole greenhouse soils in the region. The manganese values varied between 1.30 and 132.60 ppm and the average manganese value was 16.39 ppm. The detailed manganese content distribution of the soils is presented in fig. 8.  The cupper content of the greenhouse soils varied between 0.35 and 52.76 ppm and the average value was 9.22 ppm. All the greenhouse soils are adequate in cupper content so cupper deficiency will not be a problem in the greenhouses of the area. References . Bouyoucos,G.J.,A Recalibration of Hydrometer Methodfor Making Mechanical Analysis of Soil. Agron.Jour .43:434-438,1951 . Chapman.H.D., Pratt. P.F.Methods of Analysis for Soils and Waters. Univ. of California, Division of Agric. Sci, 1961. . Lindsay, W.L., Norvell,W.A., Development of a DTPA Micronutrient Soil Tet. Soil Sci.Soc. Am.Proc. 35:600-602,1969 . Ülgen, N., Yurtsever, N. Türkiye Gübre ve Gübreleme Rehberi. Köy Hizmetleri Genel Müdürlüğü Toprak ve Gübre Araştırma Enstitüsü Müdürlüğü Yayınları Genel Yayın No: 151 Teknik Yayın No: T-59 Ankara,1988 . FAO., Micronutrient, assesment at the country level: an international study. FAO Soils Bulletin by Mikko Sillanpaa, Rome, 1990 |