Yazar "Akis, Rifat" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim
    Öğe
    The Distirbution of Tensiometric Moisture Potential in Relation to Seasonal Rainfalls for a Tile Drained Clayey Soil
    (Ankara Univ, Fac Agr, 2015) Akis, Rifat
    The objective of this study was to investigate the effectiveness of tile drainage system, tile flow rates in relation to soil matric potential ranges and water table levels based on seasonal rainfalls in a heavy clayey alluvial soil profile. In order to observe water potential, drain flows, water table levels, climatic parameters, Gardner's field type irrometers/tensiometers, a weather station, digital water flow meters, automated moisture probes, and piezometers were established in Tar la 49 station with heavy clay alluvial soils, Ucgedik, the Amik Plain. Tensiometric moisture potentials in the 0-30, 30-60, and 60-90 cm layers varied from 3.8 to 16, from 12 to 16, and from 15 to 20 kPa, respectively. Drain flows of 3873 and 155611 occurred according to the given moisture potentials 5 to 7 days after rainfalls. Water levels in piezometer battery (7-8-9), parallel to the flow channel of outlet, varied from high to low; 54-132, 72-122, and 117-152 cm, respectively. The piezometer battery (4-5-6), installed between laterals, registered very rarely high water table levels greater than drain depth of 100 cm. On the other hand, the piezometers (1-2-3) farthest from the drain outlet registered the highest water table levels varying from 133 to 96, 103 to 73, and 119 to 77 cm, respectively. The rains and infiltration were effective in 0-45 cm depth. The tensiometers in deeper depths responded to the rains between 4 and 6 days. Water table fluctuations were more effective than rains on the 90 cm depth tensiometers. Piezometer heads ranged from 44 to 157 cm in the spring and early summer and 0 to 44 cm for at least 24 days in the early spring. In conclusion, tile drainage system was operable effectively while runoff flow was ponding in the field. Therefore, a combined drainage system could remedy drainage hazard in the study area.
  • Küçük Resim
    Öğe
    Mapping of total nitrogen, available phosphorous and potassium in Amik Plain, Turkey
    (Springer, 2010) Uygur, Veli; Irvem, Ahmet; Karanlik, Sema; Akis, Rifat
    Soil nitrogen, phosphorous, and potassium concentrations accurately revealed spatial distribution maps and site-specific management-prone areas through inverse distance weighting (IDW) method in the Amik Plain, Turkey. Spatial mapping of soil nitrogen, phosphorous, and potassium is a very severe need to develop an economically and environmentally sound soil management plans. The objectives of this study were (a) to map spatial variability of total N, available P, and exchangeable-K content of Amik Plain's soils and (b) to locate problematic areas requiring site specific management strategies for the nutrient elements. Spatial analyses of Kjeldhal-N, Olsen-P, and exchangeable-K concentrations of the soils were performed by the IDW method. Mean N content for surface soils (0-20 cm) was 1.38 g kg(-1), available P was 28.19 kg ha(-1) and exchangeable-K was 690 kg ha(-1) with the differences between maximum and minimum being 7.63 g N kg(-1), 242 kg P ha(-1), and 2,082 kg K ha(-1). For the surface soil, site-specific management-prone areas of Kjeldahl-N, Olsen-P, and exchangeable-K for low and high + very high'' classes were found to be 20.1-17.8%, 24.7-10.0%, and 4.1-39.6%, respectively. Consequently, lands with excessive nutrient elements require preventive-leaching practices, whereas nutrient-poor areas need fertilizer applications in favor of increasing plant production.
  • Küçük Resim
    Öğe
    Spatial variability of soil solute and saturated hydraulic conductivity affected by undrained water table conditions
    (Springer, 2015) Akis, Rifat
    Spatial information of soil solute and saturated hydraulic conductivity under undrained water table conditions can provide explicit knowledge to better manage soil and water than nonspatial management practices. This research was conducted to determine spatial structure of soil saturated hydraulic conductivity and salt content, as influenced by undrained water table conditions in the Amik Plain of Turkey. Using grid sampling, the General Directorate of Turkish State Hydraulic Works sampled the Amik Plain soils at approximately 1 600 locations, 254 of which were examined through undisturbed soil core sampling for land drainage evaluation. Geostatistical analyses revealed that the 30-60 and 90-120 cm soil layers had a shift in the particle size and were exposed to two different alluvial soil forming processes. Mean soil Ksat steadily decreased from 1.05 to 0.99 cm h(-1) and mean salt content increased from 0.307 to 0.335 % below the 30 to 60-cm layer. Correlation distance varied from 710 to 1 130 m for soil Ksat and 1 000-1 130 m for soil salt content for horizontal variograms. Nugget values of the models for soil Ksat ranged from 0.031 to 0.036, while the range of nugget was from 0.002 to 0.18 for soil salt content. Sill variance was the highest for Ksat (0.201) from 30 to 60 cm layer and soil salts (1.18) from 60 to 90 cm layer. Soil profile was moderately to heavily saline (1.69-7.73 dS m(-1)). For the vertical variograms, correlation distance was approximately 75 cm for soil Ksat and 136 cm for soil salt content. Results showed that an 1 130 m x 1 130 m subfield with 75 cm and/or deeper depth could be used for the layout of drain tiles. Further studies of long-term spatial variability of these properties under drained and undrained conditions with anisotropy are needed for sound surface and subsurface drainage system implementations in the Amik Plain.