1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Design fabrication and testing of a rainfall simulator(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1993) Kurien, E K; George, T PRainfall simulators are considered as effective aids in soil conservation research. Simulators make it possible to produce predetermined storms at any desired time and location. A rainfall simulator suitable for soil erosion studies was designed and fabricated at KCAET Tavanur. The developed simulator was tested for its performance. Erosion studies on laterite soil was conducted using the developed simulator. The rainfall simulator designed and fabricated was of an oscillating, tubing tip type. The crop former unit consisted of 112 numbers of 18 gauge hypodermic needles fitted on a 1.8 cm GI pipe network. The speed of oscillation was 8 oscillations per minute. The drop former unit was supported at a height of 3 cm above ground level. Intensity of rainfall was varied by changing the pressure of water supply to the simulator. The simulator was tested for intensity, droplet size and uniforimity of application of the rainfall produced. The intensity of rainfall was related to the pressure of water supply as 1 = 6.0386 – 31.9152 P + 177.30 P2 The drop size obtained was 2.31 mm for an intensity of 4.77 cm/hr and the corresponding drop sizes for intensities of 5.60, 6.73, 6.99 and 8.80 cm/hr were 2.20, 2.18, 1.05 and 0.80 m respectively. Christiansen’s uniformity coefficients calculated for intensities ranging from 4.77 to 8.80 cm/hr varied from 82 to 88 per cent. Experiments were also conduced to study soil loss and runoff from laterite soil. The soil loss increased with the intensity of rainfall for all the slopes studied. Maximum soil loss of 1464 kg/ha/hr occurred from a slope 20 per cent at a rainfall intensity of 8.80 cm/hr. A general trend of increase in soil loss with slope was observed. At an intensity of 8.80 cm/hr the soil loss from 5 per cent slope was 940.2 kg/ha/hr whereas the soil loss from 20 per cent slope was 1464 kg/ha/hr for the same intensity. At 5.60 cm/hr intensity of rainfall the runoff from a slope of 5 per cent was 325.33 m3 /ha/hr whereas the runoff was 432 m3 /ha/hr at 6.73 cm/hr intensity for the same slope. Empirical equations were developed for estimating soil erosion and runoff for various intensities of rainfall and land slopes. The equations are : 1. E = -982.384 + 2834.63 S + 225.239 1 (R = 0.94) 2. Q = -216.174 + 1104.65 S + 79.375 1 (R = 0.92)Item Soil erosion studies under simulated rainfall conditions in a lateritic terrain(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2014) Praveena, K K; Kurien, E KSoil erosion IS a complex phenomenon involving the detachment and transport of soil particles, storage and runoff of rainwater and infiltration. Soil erosion depends on several factors such as climate, soil type, topography, cropping and land management practices, the antecedent conditions and the size of the area under consideration. The present study was carried out in the lateritic terrain of KCAET campus, Tavanur, Malappuram District. This study was aimed at developing a rainfall simulator and studying the performance of the developed rainfall simulator, the effect of rainfall on soil loss, the effect of rainfall on runoff and developing a soil erosion model. A rainfall simulator was fabricated to study the erosion processes. Rainbird 12115118 Van Pop up sprinkler heads were used as the drop formers. The simulator evaluated for its performance. The soil was reddish brown and belonged to the textural class of sandy loam. It belonged to the Naduvattom series. The experimental set up consisted of three units viz., the runoff plot, the rainfall simulator and the runoff-sediment collection unit. Twelve runoff plots with twelve different slopes of 1.5, 2.0, 2.6, 3.0, 3.2, 4.0, 5.0, 6.0, 9.0, 10, 12 and 13 per cent in different locations, each plot with a size of2 x 1.5 m were prepared. The fabricated rainfall simulator could produce rainfall intensities varying from 8.16 to 8.80 ern/h. The uniformity of rainfall varied from 89.01 to 92.70 per cent and the average drop size varied from 1.5 to 2.8 mm. A relationship between supply pressure and intensity of rainfall as well as intensity and uniformity of rainfall was developed. Studies were conducted on soil loss and runoff at different land slopes under simulated rainfall conditions. The soil loss and runoff was found to increase with increase in rainfall intensity and land slopes and there were no much variations on runoff and soil loss at 6 to 10 per cent land slopes. A linear multiple regression analysis and 3D surface plot analysis was used to incorporate slope and rainfall intensities into a single prediction equation of soil loss and runoff using SPSS software and MATLAB package. The linear equations developed by the regression analysis are as follows: Q = 38.9451 - 11.606 S - 126.391 E = 124.356 1 - 0.807 S -951.420 (R2 = 0.649) (R 2 = 0.307) The quadratic equations developed by the 3D surface plot analysis are as follows: Q = 130.8 - 28.72 S + 48.12 1 + 2.11 S2 - 1.544 S 1 E = - 647.4 - 49.261 + 86.94 S - 0.3206 12 +6.296 S I As the variants explained were satisfactory enough to explain the runoff and soil loss, it may be concluded that the causative factors namely slope and intensity are bearing directive impact on soil erosion. A canonical analysis was worked out to determine the effect on runoff and soil loss by the vector of parameters u ing slope and intensity. Canonical R was computed and the same was 0.82034 and it is significant at 1 per cent level. Hence it may be concluded that the vector of process 'including slope and intensity as parameters together navigates the ultimate impact namely runoff and soil loss.Item Impact of fertigation and drip system layout on performance of chilli(Capsicum annum)(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2012) Nadiya Nesthad; Kurien, E KThe study “Impact of fertigation and drip system layout on performance of Chilli (Capsicum annum)” was taken up with the objective of determining the effect of fertigation, drip system layout and different levels of irrigation for chilli under plastic mulch. Different fertigation equipments like ventury injector, dosmatic fertigation unit and fertilizer tank were tested to study the hydraulic performance of the system. Ventury injector for fertilizer application was found to have high suction rate in comparison with dosmatic fertigation unit. The suction rate and motive flow rate was found to vary directly with respect to the pressure drop between the inlet and outlet of the fertigation equipment. Ventury injector can be used only if the discharge rate is above 14.6 L/min. Dosmatic fertigatrion unit and fertilizer tank can be used if the discharge rate is above 1.1 L/min and 6.6 L/min. The moisture distribution pattern under different drip field layout was observed. The moisture content near to the plant base was found to be high and decreases as the distance from the emitters increased. The effect of different irrigation levels and drip system layout under plastic mulch on the performance of Chilli (Capsicum annum), Ujwala variety was also studied. The number of branches, stem girth and yield showed significant difference between the treatments. The yield showed significant difference with different levels of irrigation and drip system layout. Maximum yield of 18.32 t/ha was observed for the treatment T5. The treatments T6 (17.952 t/ha) was on par with the treatment T5. The benefit cost ratio for treatment T5, 85 per cent of the irrigation requirement with one lateral for each row of crop was 3.8 and treatment T6, 85 per cent of the irrigation requirement with one lateral in between two rows of crop was 3.9. Even though the yield for the treatment T5 was high, the benefit cost ratio stands high for treatment T6. The high value of benefit cost ratio for treatment T6 was due to the reduction in the quantity of material for drip irrigation system