Browsing by Author "George, T P"

Now showing 1 - 19 of 19

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 P
Rainfall 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)
Design, fabrication and evaluation of the performance characteristics of hydraulic ram by varying the various parameters
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1989) Suseela, P; George, T P
In India, the agricultural production in many areas especially in hilly areas is very much affected by the non – availability of adequate power to lift water for irrigation. Main problems in enhancing irrigation facilities in hilly regions are their highly uneven topography and non availability of conventional sources of energy. The rapid depletion of conventional sources of energy and increasing demands have now focussed the attention on the need for developing a new economical and effective water lifting device which does not use the conventional sources of energy. A hydraulic ram may meet these requirements in hilly regions and can lift water without any external source of energy in the form of fuel or electricity. A hydraulic ram was designed and fabricated with cheap and commercially available materials. A constant supply head of 1.955 m was provided. Ram was designed for a maximum delivery head of 10 m. Provisions were given to vary the weight and stroke length of both the delivery valve and waste valve. A flange joint was incorporated valve and waste valve. A flange joint was incorporated between the delivery valve and air chamber to facilitate the quick opening and reinstallation of air chamber. Air chamber was fabricated with provisions to alter the volume, by changing the length of air chamber – the diameter of the air chamber was kept constant. The performance of hydraulic ram was evaluated mainly observing the delivery head – delivery discharge relationships. In each case the efficiency of the ram was evaluated. Typical performance characteristic curves were plotted for each of the changes in the conditions of operation. Effect of volume of air chamber on the performance of hydraulic ram was studied. The study revealed that the efficiency of the ram increases 1. as the weight of delivery valve increases 2. as the stroke length of delivery valve decreases 3. as the volume of air chamber increases 4. as the stroke length of waste valve decreases There is a steep reduction in delivery discharge with unit increase in delivery head. For a particular combination of waste valve, delivery valve and volume of air chamber, the maximum efficiency occurs at a moderate delivery head. For an increase in the stroke length of waste valve, there is a large reduction in best frequency. The beat frequency increases as the delivery head increases. The rate of decrease of best frequency with respect to the stroke length is higher for lower weights of was to valve. The ram stops functioning at certain low value of delivery head. This low valve of delivery head increases with increase in weight of delivery valve. Corresponding to a certain weight of delivery valve, there is a minimum weight of waste valve at which the ram functions satisfactorily. Further investigations are necessary to standardise different parts of the hydraulic rams for optimising their performance under varying conditions.
Design, fabrication and testing of an equipment to measure deep percolation
(Department of Land and water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1990) Jolly Kutty Eapen; George, T P
Because of the semi - aquatic nature, the water requirement of rice is 2 - 3 times greater than other crops. The measurement or prediction of percolation losses in field situation is of great practical significance for efficient irrigation and also for the determination of the nutrient losses. A precise knowledge of water requirement of crop attains importance for increasing production. The present investigation was taken up to design, fabricate and test an equipment to collect deep percolation water, quantify it and to assess the nutrient losses in the percolation water. The study was undertaken in ‘Mundakan’ season and the variety was ‘Triveni’. The location was the Instructional Farm of KCAET, Tavanur. The main source of irrigation water was filter point tubewell. Estimations of evaporation, transpiration and percolation were made on the basis of measurements using evaporimeter, evapotranspirimeter and field hook gauge. Vertical percolation was assessed using percolation – meter which was designed and fabricated for this study. Lateral percolation was obtained by subtracting vertical percolation from total percolation. The study revealed that the total water requirement was 1270.25 mm. The percentages of water lost by evaporation, transpiration, and total percolation are 13.69, 31.0 and 55.3. The water which is lost by vertical and lateral percolation are 59.4 and 40.6 per cent of the total percolation respectively. There was a gradual increase in the rate of evaporation during the initial stage. Then it decreased up to 65 days and then again increased up to the final stage. Rate of transpiration remained almost constant up to 10 days and then the rate slowly increased as the crop grew. The rate increased up to the booting stage. There was a gradual decrease in the rate of transpiration in the final stage. The rate of total percolation remained almost constant during the crop period. More than 50 per cent of the applied water is lost through percolation. During the initial stage, vertical percolation rate was higher than in the subsequent days. After 10 days, the vertical percolation rate remained almost constant. The rate of lateral percolation was constant during the crop period except in the sixth week after transplanting. The samples of percolation water were collected and the NPK losses due to deep percolation were analysed by the standard methods. The maximum percolation losses of applied NPK occurred on the first day of application and there was only traces from the fourth day onwards. Nitrogen and potassium losses were higher than the loss of phosphorus which was negligible. The NPK losses due to deep percolation is not much when compared to the run off losses. This may be due to the fact that the NPK content in the solution gets fixed in the soil as it percolates down through the soil. So the water that goes beyond the root zone will contain only very little NPK. The equipment fabricated for the measurement of deep percolation losses worked satisfactorily. Knowledge of water requirement of rice will greatly help in the efficient utilisation of available water.
Determination of constants in uniform flow formula for small discharges in open channels
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1990) Parvathy, S; George, T P
An attempt was made to find out the constants in the general uniform flow formula for small discharges less than 10 1/s in cement lined and earthen channels. These constants were compared with the constants in the well known and widely used uniform flow formulae such as Manning’s and Chezy’s equation and checked their validity for small channels. Experiments were conducted for different discharges varying from 1 to 9 1/s and for different slopes of 1/2000, 1/3000, 1/4000 and 1/5000 in cement lined and earthen channels. With the help of a computer, analysis was made to establish a relationship between velocity v, hydraulic radius R and slope S. The expirical equation obtained are In cement lined channel V = 9.199 R0.7591 S0.1103 i.e. V = 1/0.1087 R0.7591 S0.1103 In earthen channel V = 47.2286 R0.844 S0.307 i.e. V = 1/0.0212 R0.844 S0.307 From the comparison of actual velocity with velocity obtained by using Manning’s equation, it was found that Manning’s equation was not applicable to small channels having discharges less than 10 1/s. In both the channels, actual velocity was roughly two times greater than the Manning’s velocity. The average ratio of actual and computed velocity using the best fit equations and the coefficient of determinations in the two cases were near unity. Hence the best fit equations obtained in the study are recommended for the design of small channels. Manning fixed the value of exponent of S as 0.5 based on some theoretical assumptions. So it was decided to find the value of n and the exponent of R in both the channels by fixing the value of exponent of S as 0.5. The equations obtained are In cement lined channel V = 1/0.00428 R0.7827 S0.5 In earthen channel V = 1/0.00408 R0.8696 S0.5 These equations were good but their reliability were less than that of the previous equations.Since Manning’s equation is an university accepted form, comparison was made between the recommended n values and the n values obtained in the study by fixing the value of exponent of R and S as 0.67 and 0.5 respectively. The equations obtained are In cement lined channel V = 1/0.00609 R0.67 S0.5 In earthen channel V = 1/0.00778 R0.67 S0.5 Though the reliability of these equations were comparatively less than the earlier cases, it gave reasonably good results. So these equations are also recommended for the design of small channels with different n values for cement lined and earthen channels. Chezy’s constant C was determined from the best fit equations by fixing the value of exponent of R and S as 0.5. The equations obtained in two channels are In cement lined channel V = 94.91√RS In earthen channel V = 74.771√RS These C values obtained are recommended for the design of small channels in Chezy’s equation than the C values obtained from Manning’s and Kutter’s equations using Manning’s recommended n values. Soil in which earthen channel was constructed was classified based on texture. Since the soil was sandy loam, the best fit equation obtained in earthen channel is applicable only for sandy loam soil.
Development and evaluation of a mechanical collecting system for salvinia weed
(Kerala Agricultural University, 1987) Sankaranarayanan, M R; Jose Samual; George, T P
Salvinia harvesting machine is a mechanical device suitable for removal ofsalvinia weed (locally known as African Payal) from the waterways. The harvesting capacity of the equipment is 16 t/h. The estimated cost of the machine is about Rs. 5000 besides the cost of the high head centrifugal pumpset. The operating cost of the equipment is calculated as Rs. 28 per hour and this amounts to a weed clearing cost of Rs. 280from one hectare of weed infested rice field.
Development of small scale equipment for extraction of Cocoa butter and production of cocoa powder
(Department of Agricultural Engineering, College of Horticulture, Vellanikkara, 1982) Ganeshan, V; George, T P
The primary objective of this project was to evolve a viable technology and equipment system for small scale processing of cocoa beans. The study mainly concentrated on the development of an extraction unit for the separation of butter from cocoa mass. Various equipment required for small scale processing of cocoa beans were either identified or designed.
Effect of different tillage methods on percolation loss in rice fields
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1993) Mini, P K; George, T P
Water loss by deep percolation constitutes a major part of the total water loss from the rice fields. Puddling is widely carried out in rice field to create favourable soil condition for the growth of rice plant and to reduce the loss of water through percolation. An experiment was conducted in sandy loam soil to determine the effect of different tillage methods on percolation loss of water and to evaluate their effect on grain yield. The treatments choosen for the study were puddling with power tiller, puddling with tractor cage wheel, puddling with animal drawn puddler (TNAU helical blade type), compaction using roller and puddling with country plough along with planking (control). The experiment was laid out in randomized block design with five replications. Seedlings of short duration rice variety ‘triveni’ were used for transplanting. The daily water loss from the experimental plots was measured using field hook guage. The water loss through percolation was obtained by subtracting the evapotranspiration from the total water requirement. The mean water requirement was highest in the plots puddle with country plough (1609.3mm) and was lowest in the plots puddled with tractor cage wheel (1510.3mm). The percolated water constitute 62 per cent and 64.34 per cent of the total water requirements in the plots puddled with tractor cage wheel and country plough respectively. The lowest mean percolation of 936.12 mm was recorded in the plots puddle with tractor cage wheel. It was followed by puddling with power tiller (949.92 mm), compaction using roller (966.02mm), puddling with animal drawn puddler (1025.02mm) and puddling with country plough (1035.12mm). However, the treatments did not differ significantly regarding the loss of water through percolation. The percentage variation of the percolated water for the different treatments over the control was maximum (17.66 per cent) during the vegetative phase. The variation from the control decreased during the latter two stages and was minimum during the ripening stage (3.89 per cent). The plots puddle with tractor cage wheel recorded the highest yield (11.26 kg/plot) compared to other treatments. The water use efficiency varied from 15.68 kg/ha-cm (puddling with country plough) to 18.64 kg/ha-cm (puddling with tractor cage wheel). The yield and water use efficiency also did not differ significantly among the treatments. The reason for the insignificant among the treatments regarding the loss of water through percolation, yield and water use efficiency could be attributed to the sandy loam nature of the soil since the response of rice plant to various tillage methods depends up on soil texture. It is known that the surface soil aggregates play a major role in controlling the infiltration rate of soil. Since the soil in the experimental field consists of 10 per cent gravel, 65 per cent sand, 12.5 per cent silt and 12.5 per cent clay, the amount of finer particles available for clogging of pores and surface seal development are less in these type of soil, which might be the reason for the treatments not showing any significant variation in the water loss through percolation. From the study undertaken, it was concluded that different tillage methods have no effect in light textured soil in controlling the loss of water through percolation.
Effect of distributor on flow rate in a drip irrigation system
(Kerala Agricultural University, 1994) Susan Cherian, K; George, T P
The effect of distributor on flow rate was studied. For each diameter of microtube, different length combinations of inlet tubes and drippers were tried. It was found that the discharge rate from the system with the distributor was higher than that of microtube having the same length and size. The frictional losses, the combined minor losses and distributor losses for different flow conditions were estimated. From the observed data, a few combinations which satisfied the requirements, viz., length, discharge and pressure head were selected to use as a guideline for design of the KAU drip irrigation system.
Effect of leaf area on tuber yield of irrigated tapioca
(Kerala Agricultural University, 1982) Sushama, P K; Pillai, G R; George, T P; Jose Mathew
Evaluation of different methods for reducing percolation loss of water in rice fields
(Kerala Agricultural University, 1983) George, T P; Balakumaran, K N; Jose Mathew; Sushama, P K; Pillai, G R; Kuruvilla Varghese
Afield experiment was conducted in a sandy loam soil of the Agronomic Research Station, Chalakudy for five years (1974-'80 to study the efficiency of puddling with different implements (power tiller, country plough and wetland puddler), soil dressing with lateritic,loam and sub-soil compaction at 30 cm depth in reducing percolation loss in rice fields. The study showed that these methods neither effectively reduced the water loss nor influenced the grain yield.
Evaluation of drip and conventional methods of irrigation In amaranthus and brinjal
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1988) Sheela, E V N; George, T P
Forms of water loss and water requirement of rice in kole lands
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1988) Lissy Devid Chirayath; George, T P
Rice is the most important and extensively cultivated food crop in Kerala. Efficient use of water for crop production has been a major concern for centuries. As the water needs of rice is many times greater than other crops, a precise knowledge of water requirement of crop attains importance for increasing production. The present investigation was taken up to estimate the losses through evaporation, transpiration, percolation and to assess the total water requirement of a medium duration rice variety Jaya, in Punja season in Kanjany Kole lands in Trichur district, which has not been assessed so far. The Kole areas are reclaimed lake beds below mean sea level. The main source of irrigation water to the Kole lands is from the Peechi irrigations system. The experiment was conducted during Punja season of 1986 in Kanjany Kole lands. Estimations of evaporation, transpiration and percolation were made on the basis of measurements, using evaporimeter, evapotranspirimeter and field hook gauge. From the study it was revealed that the total water requirement was 2134.22 mm. Percentages of water lost by percolation, transpiration and evaporation were 70.34, 17.32 and 12.34 respectively. Rate of evaporation was almost constant during first twenty days, then started decreasing up to 69 days and then onwards was almost constant during the final stage. Rate of transpiration remained almost constant up to ten days, then started increasing up to fifty days and then remained almost a constant up to final stage. Rate of total loss of water was increasing from transplanting, reached a maximum of 28.6 mm after 26 days, then started decreasing up to final stage. When the level of water in the canal is very low, this study has shown that the percolation loss in Kole lands could be as high as 28.6 mm. So by maintaining water level in the canal, we can save wastage of water due to deep percolation. Shortage of irrigation water is a serious problem in most of Kole area during Punja season. Knowledge of water requirement of rice in kole lands will greatly help in efficient utilisation of the limited water available in the reservoirs.
Hydraulics of border strip irrigation on level or nearly levely rice fields
(Department of Agricultural Engineering, College of Horticulture, Vellanikkara, 1983) Visalakshi, K P; George, T P
In Kerala, more than seventy per cent of the double cropped rice fields lie fallow during summer months. Rice cannot be grown during this season because of the limited availability of water and the very low water use efficiency that can be attained during this season. The development of a technology for efficient use of limited water available during summer is necessary to make use of these rice fallows for cultivating crops other than rice. As most of the area is under paddy during first and second crop seasons, the level of the land cannot be disturbed. But now, there is no any satisfactory method of irrigation suitable for irrigating nearly level rice fallows. The objective of this project was to study the hydraulics of border strip irrigation in nearly level lands and to recommend suitable specifications. The experiment was done at the Agronomic Research Station, Chalakudy during 1981-82. It consisted of five replications of four treatments. The treatments were two widths of 4m and 6m combined with two discharge rates of 2 1/sec/m and 4 1/sec/m, the length of strip in all cases being 45m. The surface gradient was 0.03815 per cent in the direction of natural slope. Altogether seven irrigations were given at an interval of seven days. Blackgram seeds were dibbled in the field after the first irrigation and cultural practices as recommended in the package of practices were followed. The time of advance of waterfront, the depth of flow and the time of recession of tail water were observed at every 5m length for each strip. The cutoff length was chosen as 77 per cent from the upstream end. The hydraulic gradient, hydraulic resistance and velocity of flow for each irrigation were determined. The advance and recession curves were drawn. The results of the experiment revealed that a discharge rate of 2 1/sec/m is the best for irrigating nearly level borders of 4m and 6m widths. The depth of irrigation could be limited to 5 cm even in soils having high rate of infiltration. The lower discharge rate of 2 1/sec/m reduced the time of ponding at the downstream end and this minimized the wastage due to deep percolation at the downstream end. Soil erosion in the strip was minimum at this rate of discharge, and long strips upto 45m length in loamy sand could be irrigated with high degree of efficiency. As only a low rate of discharge is required to practice this method, even in areas having limited availability of water, an additional crop can be profitably raised. It is estimated that the water needed to raise one hectare of rice in summer months can be more profitably used to raise about 4 ha. of any other crop. Hence, growing rice during summer season should be discouraged and the land should be utilized to raise other remunerative crops like pulses, oilseeds and vegetables. Now the Government has decided to provide water not only for rice but also for other seasonal crops during the summer months. But now, there is no satisfactory method of irrigation for nearly level fields. Border strip method of irrigation is hardly practiced anywhere in Kerala, even though this is a very popular method in the other parts of India for raising cereals, pulses and oilseeds. However, this method is practiced there on sloping lands. Since the present study revealed that this method can be practiced efficiently on level or nearly level fields, this is best suited for the rice fallows during the dry season. Most of the paddy fields have a mild natural slope in one directions. This slope can be used to advantage by laying the strips in the direction of natural slope. This method can be recommended to the farmers for raising a crop in the rice fallows. The specifications of border strips for nearly level lands are as follows: _______________________________________ Length of border - Upto 45m Width of border - 4 – 6m Rate of flow - 2 1/sec/m Slope - should be laid in the direction of natural slope Height of bunds separating the strips - 20 cm Base width of bunds - 30 cm
Hydraulics of KAU drip irrigation system
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1988) Susan Cherian, K; George, T P
Irrigation advancements within the last decade has been astounding. Drip irrigation is one of the latest innovations for applying water to the field and it represents a definite advancement in irrigation technology. An attempt was made to study the hydraulics of microtube emitters of 1-3 mm size, Black polyethylene tube of 1" was used as main line. In the main line, three laterals of 1/2 diameter were connected. Discharge measurements were taken at different pressure heads.The total energy drop (H) in a microtube emitter is the summation of friction loss (Hf) and minor loss (Hm). There was no empirical equation available for calculating the friction drop from a microtube of size less than 4 mm. With the help of a computer, analysis was made to establish the relationships between pressure head H, length L, diameter D and discharge Q. The empirical equations obtained are 1. Combind flow condition H = 0.01402 Q1.23938/D3.54926 L0.86030 2. Turbulent flow condition H = 0.00764 Q1.82655/D4.61537 L0.77823 3. Flow in transition region H = 0.00817 Q1.56882/D3.83531 L0.83541 4. Laminar flow condition H = 0.00796 Q1.23461/D3.59105 L0.98712 Where Q = discharge, 1/hr L = length of tube, cm D = diameter of tube, mm The minor losses, viz. exit, entry, losses due to fittings and sudden contration can be expressed as a function of velocity head. The minor loss was significant because of the smaller size and short length of the microtube. The numerical solution for minor loss coefficient K was obtained in order to make the power of L unity in the estimating equations for head loss due to friction. The equations obtained are 1. Combind flow Hm = 2.34 V2/2g 2. Turbulent flow Hm = 2.14 V2/2g 3. Flow in transition region Hm = 3.18 V2/2g 4. Laminar flow Hm = 0.84 V2/2g Where V = Velocity, m/s G = acceleration due to gravity, m/s2 The empirical equations for friction drop were developed for different flow condition by fitting multiple log linear regression equations. The equations obtained are 1. Combined flow Hf = 0.00737 Q1.18905/D3.58352 L 2. Turbulent flow Hf = 0.00359 Q1.74866/D4.80544 L 3. Flow in transition region Hf = 0.00397 Q1.46302/D3.74436 L 4. Laminar flow Hf = 0.00743 Q1.22546/D3.58420 Similar to Blasius and general equations, the following equations were developed for friction factor in turbulent and laminar regions. f = 0.248/Re0.25 and f = 67.2/Re where f = friction factor Re = Reynolds number The KAU drip system has an additional component ‘Distributor’. Experiments were conducted to study the effect of distributor on flow rate. It was observed that the discharge rate was higher from the system with distributor than that of microtube having the same length. The frictional losses and the combined loss of minor and distributor for different flow conditions were estimated. Few combinations which satisfy the requirements of discharge, length and pressure head were selected for the design purpose of KAU drip irrigation system. The effect of clogging on discharge rate was studies and it was found that clogging was higher in 1 mm tube than the 2 mm and 3 mm tubes. Experiments were conducted to estimate friction loss in laterals. Hazen – Williams equation was found suitable for turbulent region and not for laminar and transition region. By adopting drip system we can bring more area under cultivation by maximum utilisation of available water. By combining improved agronomic practices along with an efficient drip irrigation system, it is possible to bring about a substantial progress in the farm front.
Hydraulics of tile drains in peat and muck soils
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1989) Raju, T D; George, T P
Agricultural drainage is the removal of excess water, known as free water or gravitational water, from the surface or below the surface of farm land so as to create a favourable soil conditions for crop growth. The process of removing the excess water from land surface is called surface drainage. The excess water saturates the pore space of the soil, the process of its removal by downward flow through the soil is known as subsurface drainage or internal drainage. In the case of kari land of Kuttanad the field level is below the surrounding waterbodies, there is always an upward movement of water from the subsoil to the surface. The upward movement of water from the subsoil brings along with it harmful byproducts of decomposition of organic matter which when come into contact with roots of plant adversely affect the gorwth and yield. With regard to the experiment on finding the suitable envelope material for subsurface drainage system in peat and muck soils revealed that the river sand (big size) was adequate in terms of filtration quality and hydraulic conductivity. Thus river sand (big size) could be considered as a suitable envelope material for subsurface drainage experiments. In the second experiment the performance of tile drains viz. PVC and baked clay pipe were assessed. From the comparison of head loss fraction and entrance resistance between PVC and baked clay pipe showed that the performance of baked clay pipe was good compared to PVC pipe. Considering the performance and economical reasons related to cost of baked clay pipe and its local availability, the use of the same as tile drains in peat and muck soils was confirmed. A close study of weekly values of EC of irrigation and subsurface drainage water revealed that a quantity of 124.80 kg of salts/ha/cm drop of drained water, could be washed off from the experimental area. From the observations on the growth and yield attributing characters it could be concluded that subsurface drainage was effective upto 30 m spacing. However, further studies are to be carried out for finding out a higher spacing. Economic analysis related to subsurface drainage using tile drains and envelop material (river sand) for a 100 ha area revealed that this project is economically and financially viable.
Infiltration opportunity time in level or nearly level borders
(Kerala Agricultural University, 1987) Visalakshi, K P; George, T P
The study was conducted in 1982 with an objective of finding out the infiltration opportunity time in nearly level border strips. The results revealed that a discharge rate of 2 l/s/m is the best for irrigating nearly level borders of 4-6 m width. This discharge rate gives almost equal opportunity time throughout the entire length of the strip excepting at the downstream end, thus giving better distribution efficiency. The recommended length of strip is upto 45 m and these can be laid in the direction of natural slope.
Inflow rate AMD cutoff ratio for irrigation in nearly level border strips
(Kerala Agricultural University, 1987) Visalakshi, K P; George, T P
The experiment was done to study the hydraulics, of border strip irrigation in nearly level lands, during 1982. The study revealed that the discharge rate of 2 l/s/m and the inflow cutoff length of 77 per cent of the strip length are optimum for uniform distribution of water for the following reasons: 1) The depth of irrigation could be limited to 5cm even in soils having high rate of infiltration; 2) The lower discharge rate of 2 l/s/m reduced the time of ponding at the downstream end and this minimised the wastage due to deep percolation at the downstream end; 3) Soil erosion was minimum at this rate of discharge; 4) Long strips upto 45 m length in loamy sand could be irrigated with high degrees of efficiency; and 5) As only a low rate of discharge was required to practise this method, even in areas having limited availability of water an additional crop could profitability be raised.
Performance study of hydraulic ram by varying length and inclination of supply pipe
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1991) Rathnakumar, V K; George, T P
In India, the agricultural production in many years is hampered by the non availability of the adequate power for irrigation. The shortage of power often affects the lift irrigation project. Main problems in enhancing irrigation facilities in hilly regions are their highly uneven topography and non availability of conventional sources of power. The increasing exploitation of conventional energy sources for meeting the increasing power demands is becoming expensive. Under such circumstances, devices like hydraulic rams are to be efficiently designed for lifting water in regions where adequate supply of water and favourable conditions for installations for hydraulic rams exists. Hydraulic ram is a simple automatic device, which uses the kinetic energy of a large quantity of flowing water available at lower elevation to lift a portion of it to a higher elevation. The simplicity of construction and the automatic operation make it especially adaptable to remote areas. The performance study of hydraulic ram was evaluated mainly by observing the delivery head and delivery discharge relationships. In each case, the efficiency was evaluated. Typical performance characteristics were plotted for the changes in conditions of operations. Effect of the performance of the hydraulic ram was studied by changing length of supply pipe, L/D ratio of Air chamber, volume of Air Chamber and inclination of supply pipe. The major findings of the research work are : 1. The ram shows best range of efficiency of operation for 14 and 15 metre lengths of supply pipe. 2. The L/D ratio of Air chamber have no significant effect on the values of delivery discharge, efficiency and delivery head for a given volume. 3. The delivery discharge increases with increase in volume of Air chamber, but the rate of increase in delivery discharge decreases with increase in volume of Air chamber. 4. The continuous operation of hydraulic ram have no significant effect in higher volumes of Air chamber. 5. The hydraulic ram shows best range of efficiency of operation at 7 degree inclination of supply pipe than the 8.5 and 6 degree inclinations.
Relative efficiency evaluation of drip and conventional methods of irrigation ashgourd and cucumber
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1989) Sheeja A Andezhathu; George, T P