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20092
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Subject: Soil and Water Engineering × End date: 2009 × Start date: 2009 × Type: Thesis ×
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    Simulation of salt load through sub-surface drainage system using DRAINMOD-S model
    (PUNJAB AGRICULTURAL UNIVERSITY, 2009) Poonam Kiran; J. P. Singh
    The water management simulation model DRAINMOD-S was calibrated and validated using 3 years (1995-1997) experimental field data from the installed subsurface drainage system at 1.8 m drain depth with 40, 60 and 80 m drain spacing at Golewala watershed, Fridkot. The parameters that were determined to be most effective in changing the model output were lateral saturated hydraulic conductivity, drain depth and drain spacing. The reliability of model has been evaluated by comparing observed and simulated values. The calibrated and validated model was used to predict the salt concentration for five consecutive years (1998-2003). The average soil salinity of root zone decreased from 1417 to 1083, 1523 to 1097 and 1167 to 789 ppm, at the end of five year (2003) for 40, 60 and 80 m drain spacing respectively. The Root mean square error, model efficiency and correlation coefficient between observed and simulated salt concentration ranged from 6.49 to 38.43 ppm, 0.647 to 0.834 and 0.957 to 0.999 for three mentioned drain spacing respectively. These values are quite comparable to values reported by others in similar model validation studies. The overall performance of DRAINMOD-S was satisfactory and can be applied for design and evaluation of subsurface drainage system at Punjab and other parts of country in similar conditions.
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    Modeling Salt and Moisture Distribution in Soil Profile Under Drip Irrigation with Saline Water
    (PUNJAB AGRICULTURAL UNIVERSITY, 2009) Dhananjay D. Nangare; K.G. Singh
    The experiment was conducted at Central Institute of Post Harvest Engineering and Technology (CIPHET), Abohar in 2009-10 to study the effect of different salinity levels of irrigation water on yield and quality of tomato crop under three irrigation level 0.6, 0.8 and 1.0) and three discharge rates of emitters (1.2, 2.4 and 4.2 lph). The five different salinity levels of irrigation water was prepared by mixing fresh and saline water in 100:0, 75:25, 50:50, 25:75, 0:100 percent fresh and saline water. The results revealed that the crop yield decreased with increase in salinity ratios of irrigation water. The yield decreased with increase in discharge rates of emitters. The yield increased with increase in irrigation level from 0.6 to 1.0. The yield was found maximum when fresh water is applied with discharge rate of 1.2 lph and with irrigation level of 0.8. The yield under each salinity of irrigation water treatment was found significantly different to each other. The lower rate of water application reduced the salinity in soil profile compared to higher rates of emitter discharge rates. The quality parameters TSS, acidity and ascorbic acid were found increased with increase in salinity of water treatment. The SALTMED model was used for simulating the soil moisture, salinity (Ec) and crop yield under different ratios of salinity of irrigation water and different discharge rates of emitters. The close agreement was found between the observed and simulated values. The overall average relative error between the simulated and observed values was found 11.03 percent, 17.16 percent and 9.26 percent for soil moisture, soil salinity and crop yield, respectively.