Low Pressure Low Cost (LPLC) Drip Irrigation System Design|Modern methods of irrigation|
Economic Feasibility of Low Pressure Low Cost (LPLC) Drip Irrigation System
Drip Irrigation, Irrigation System,
The field experiment was conducted to evaluate the economic feasibility of LPLC drip system for broccoli and tomato with four treatments. Daily drip irrigation maintained soil moisture near field capacity in 30 and 60 cm depth of soil profile. The seasonal water requirement was found to be 20.08, 19.68, 18.61 and 21.06 cm respectively for treatments T1, T2, T3 and T4 and corresponding WUE are 1.46, 2.85, 3.41 and 0.82 t/ha-cm.
The mean yield of fruit of broccoli and tomato in treatment T1 (1.01 kg/plant and 29.27 t/ha) followed by T4 (0.60 kg/plant and 17.33 t/ha) and T3 (2.19 kg/plant and 63.46 t/ha) followed by T2 (1.93 kg/plant and 56.03 t/ha) respectively. The developed system has payback period of one season only, benefit to cost (B/C) ratio ranges from 1.52 to 5.31 without subsidy and 4.28 to 8.30 with subsidy. Thus, appropriate, affordable, accessible, low operation and maintenance cost, users friendly LPLC drip irrigation system is better alternative for small land holders.
INTRODUCTION OF LPLC drip irrigation system
In
Drip irrigation system offers unique agronomical, agro technical and economical advantages for efficient use of valuable water resources. However, the initial cost of drip irrigation limits its scope for large scale adoptions. The Indian government has sought to promote pressurized irrigation technologies primarily by subsidizing the cost of equipment. Despite subsidies of as much as 75 per cent of total cost of equipment, the rate of adoption is very slow and uneven. The Rajasthan State Government approved rate of 70 per cent subsidy ranging from Rs 19206 to Rs 163400 per hectare for drip irrigation.
The present drip irrigation system technologies are expensive and fit for use only in large fields. International Development Enterprises-India (IDEI) embarked upon the innovative adaptations of
There is a need to develop an efficient suitable low pressure low cost (LPLC) drip irrigation system having working head of more than 3 m with higher distribution uniformity, constructed with locally available materials that would be adoptable and affordable for small land holders.
It was surveyed3 on existing treadle pumps; low-cost drip irrigation and water storage systems reported that 550 million of the current 1.1 billion people earning less than $1-a-day earn a living from agriculture in developing countries. A revolution in water control is needed to develop and mass-disseminate new, affordable, small-plot irrigation technologies. A revolution in agriculture is required to enable smallholders to produce high-value, marketable, labor-intensive cash crops. A revolution in markets is needed to open access to markets for the crops they produce and the inputs they need. Finally, a revolution in design, based on the ruthless pursuit of affordability, is needed to harness shallow groundwater.
Scientific water management, farm practices and drip system should be adopted wherever feasible. The development of an efficient, reliable and low cost drip system that fits the needs of small farmers in developing countries has long been recognized as a critical need. The objectives of present investigation were to develop a low cost efficient suitable drip, fabricated with materials available in local market, which is adoptable and affordable for small land holders.
Drip irrigation system offers unique agronomical, agro technical and economical advantages for efficient use of valuable water resources. However, the initial cost of drip irrigation limits its scope for large scale adoptions. The Indian government has sought to promote pressurized irrigation technologies primarily by subsidizing the cost of equipment. Despite subsidies of as much as 75 per cent of total cost of equipment, the rate of adoption is very slow and uneven. The Rajasthan State Government approved rate of 70 per cent subsidy ranging from Rs 19206 to Rs 163400 per hectare for drip irrigation.
The present drip irrigation technologies are expensive and fit for use only in large fields. International Development Enterprises-India (IDEI) embarked upon the innovative adaptations of
There is a need to develop an efficient suitable
It was surveyed3 on existing treadle pumps; low-cost drip irrigation and water storage systems reported that 550 million of the current 1.1 billion people earning less than $1-a-day earn a living from agriculture in developing countries. A revolution in water control is needed to develop and mass-disseminate new, affordable, small-plot irrigation technologies. A revolution in agriculture is required to enable smallholders to produce high-value, marketable, labor-intensive cash crops. A revolution in markets is needed to open access to markets for the crops they produce and the inputs they need. Finally, a revolution in design, based on the ruthless pursuit of affordability, is needed to harness shallow groundwater.
Scientific water management, farm practices and drip system should be adopted wherever feasible. The development of an efficient, reliable and low cost drip system that fits the needs of small farmers in developing countries has long been recognized as a critical need. The objectives of present investigation were to develop a low cost efficient suitable drip, fabricated with materials available in local market, which is adoptable and affordable for small land holders.
MATERIALS USED IN DRIP IRRIGATION AND METHODS FOR DRIP IRRIGATION system
The field experiment was conducted in 2008-09 at Horticulture Farm, Rajasthan College of Agriculture, Udaipur. Krishak Bandhu (KB) drip irrigation system consisted of KB pressure treadle pump, KB pipes (submain and laterals), microtubes and its necessary accessories with pressure drum (200 l) and medical infusion set here after referred as medi-emitters were used. MS Drum was used as buffer pressure tank. The capacity of pressure treadle pump varies from 3000 to 5000 l/h with delivery head up to 13 m. One man can operate treadle pump for one hour continuously.
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The irrigated field (25 m x 25 m) was divided into four subplots (12.5 m x 12.5 m) and pressure drum (source) was kept in the
The field experiments were conducted on different aspects having level ground and 0.5 % up slope. The effects of various independent parameters on different aspects for tomato and broccoli, such as vegetative growth parameters, crop water requirements, water use efficiency, and cost economics were evaluated.
Treatments combinations were as under
T1: Broccoli grown on level ground with medi-emitters
T2: Tomato grown on 0.5 % up slope with medi-emitters
T3: Tomato grown on level ground with microtubes
T4: Broccoli grown on 0.5 % up slope with microtubes
System was operated under 6 m pressure head, discharge of emitters and its hydraulic parameters were evaluated and application time was calculated on the basis of Kc and pan evaporation. Irrigation was scheduled daily.
The experiment was laid out with four treatments, which were treated as twenty-one replication (without treatment) for randomized block design (RBD). Each subplot was comprised of 21 numbers of rows with 566 numbers of plants, out of which 5 plants were selected randomly as observational plants. Field layout of KB pressure treadle pump for one treatment is shown in Fig. 1 and overall view of experimental site is shown in Plate No. 1.
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The economy of a particular crop was assessed through analysis of detailed cost and economic return. The cost includes total cost, variable cost, fixed cost and cost per hectare of the output produced. The net economic return includes income obtained from produce. Finally, the benefit-cost ratio analysis was performed to judge the economic feasibility of LPLC drip irrigation system. The economic analysis was conducted per hectare of cultivated area under test crop.
Effective rainfall was determined using dependable rain methodology developed by FAO4. Estimating dependable rainfall, the combined effect of dependable rainfall (80 % probability of exceedance) and estimated losses due to runoff and percolation were considered. Following formula was used for calculation of effective rainfall .
Peff = 0.6 Ptot – 10 for Ptot<70 mm ….1
Where,
Peff = monthly effective rainfall, mm
Ptot = monthly total rainfall, mm
Daily soil moisture measured before irrigation at 30 cm and 60 cm depth of soil profile using AIC tensiometer. 10 cbar represents the field capacity of soil. Fitted equation is given below
% moisture content = 39.57(cbar)^0.2398 …. 2
Design of Low Pressure Low Cost (LPLC) Drip Irrigation System
The system was designed on the basis of climatologically data, constructed with locally available materials and components available at IDEI, Ahmedabad. The William-Hazen formula was used for calculation of head loss.
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Pan evaporation method was used for estimating crop water requirement5.
Volume of water required
V= (CA * PE *Pc *Kc*PWA )/Eu ………… 3
where, V= Volume of water required ,
CA= Crop area (m2)
PE= maximum pan evaporation (mm/day)
Pc= pan coefficient
Kc= crop coefficient
PWA= Percentage wetted area, (%)
Eu= emission uniformity, decimal.
Measurements of soil water content
Soil water content, vegetative growth parameters, crop water requirements, water use efficiency, and economic profitability were used to evaluate the overall performance of each treatment. Soil water content (SWC) measurements were taken throughout the experiment at 30 cm and 60 cm depth of soil profile using AIC tensiometer before irrigation. Gravimetric method was used for calibration of tensiometer. Soil-water retention curve was prepared from different soil samples having different tensiometer readings.
Vegetative growth parameters included four biometric parameters, above ground biomass (AG biomass), fruit mass (FM), crop residue (CR), and root mass (RM) were measured at the time of harvest. The fresh and dry weight of each aforementioned biometric parameter was measured.
The Water use efficiency (WUE) is one of the best tools for the evaluating the performance of different irrigation treatments. WUE was calculated as the ratio of the crop yield (t/ha) to the total seasonal irrigation water applied (cm) during the field growing season.
The economic viability of each irrigation treatments was calculated considering each treatment was operated on a 156.25 m2 (566 plants). The total amount of fruit mass produce was determined by average yield of randomly selected 5 plants within the plot and price based on market rate.
RESULTS AND DISCUSSION
The study was conducted to find the economical feasibility of LPLC drip irrigation system.
Design of Low Pressure Low Cost (LPLC) Drip Irrigation System
The detail of various design and performance parameters for 6 m head are shown in Table 1.
Table 1 Design and performance evaluation of
S.No. | Description | Treatments | |||
T1 | T2 | T3 | T4 | ||
1 | Topography of field | level | 0.5% up slope | level | 0.5% up slope |
2 | Crop type | Brocolli | Tomato | Tomato | Brocolli |
3 | Crop factor, Kc | 1.05 | 1.15 | 1.15 | 1.05 |
4 | Type of dripper | Medi-emitters | Medi-emitters | Microtubes | Microtubes |
5 | Average discharge of emitter, l/h | 2.29 | 2.11 | 1.05 | 0.86 |
6 | Irrigation time, h | 0.3 | 0.38 | 0.71 | 0.85 |
7 | Distribution uniformity, EUf(%) | 94.65 | 89.70 | 95.79 | 89.08 |
8 | Head loss in lateral, cm | 0.5 | 0.43 | 0.12 | 0.08 |
9 | Head loss in submain, cm | 14.04 | 11.94 | 3.3 | 2.3 |
10 | Total head loss from lateral and submain, cm | 14.54 | 12.37 | 3.42 | 2.38 |
11 | % head loss from operating head 6 m | 2.42 | 2.06 | 0.57 | 0.40 |
NB: | 26 mm LLDPE pipe (ID = 20 mm) and 32 mm LLDPE pipe (ID = 26 mm) | ||||
KB pipes were only available at IDE, Ahmedabad. |
Irrigation Scheduling and Crop Water Requirements
Quantity of irrigation water applied depends upon crop coefficient (KC), pan coefficient (KP), daily pan evaporation, per cent wetted area, crop area and uniformity of system. Irrigation application time depends upon crop water requirement and discharge of emitters. Daily application time under 6 m operating head was in the range of 0.14 h (2.11 l/h) to 0.85 h (0.86 l/h). Lower application time (0.14 h) was during initial crop phase and at low temperature with high discharge emitters (medi-emitters) when crop water requirement was less where as large application time (0.85 h) was applied during crop development phase with high temperature and low discharge emitters (microtubes).
It is revealed from Table 2 that total depths of applied water
Table 2 Seasonal water requirement and consumptive use
Treatments | Total RainfallReceived duringCrop Period,mm | Seasonal Water Requirement, mm | ConsumptiveUse (CU) mm | ||
IrrigationWaterApplied,mm | EffectiveRainfall, mm | Total mm | |||
T1 | 61.00 | 174.25 | 26.00 | 200.85 | 200.85 |
T2 | 61.00 | 170.19 | 26.00 | 196.79 | 196.79 |
T3 | 61.00 | 159.44 | 26.00 | 186.04 | 186.04 |
T4 | 61.00 | 184.04 | 26.00 | 210.64 | 210.64 |
Moisture Content
Soil water content at field capacity was found to be 22.78 %. Daily drip irrigation maintained soil moisture near field capacity in 30 cm and 60 cm depth of soil profile. In general, 20
Vegetative Growth Parameters of drip irrigation system
The details of biometric parameters for all the treatments are presented in Table 3. Treatments T1 and T3 performed better than T2 and T4 with respect to vegetative growth parameters. From the data of growth attributes (plant height, number of leaves, stem girth, ground coverage, number of fruits, number of branch/secondary head, leaf area, leaf area index, root growth, yield and quality of fruits, wet and dry matter content) it is concluded that the treatments T1 and T3, performed better than T2 and T4. The mean yield of fruit kg/plant of broccoli and tomato in treatment T1 (1.01 kg) was higher than that in T4 (0.60 kg) and T3 (2.19 kg) followed by T2 (1.93 kg) respectively. Yield of fruit (per ha) of broccoli and tomato in treatment T1 (29.27 t/ha) followed by T4 (17.33 t/ha) and T3 (63.46 t/ha) followed by T2 (56.03 t/ha) respectively. Ultimately, farmers are most concerned with fruit mass produced as this determines food production and/or cash income. Fruit mass had significant variation in case of treatments T2 and T3 where as insignificant in case of T1 and T4 (p ≤ 0.05). The vegetative growth parameters were high and superior quality in treatments T1 and T3 compared to T4 and T2. Yield of broccoli and tomato under different treatments are shown in Fig.2.
Similar, higher yield of tomato (67.3 t/ha) was reported for drip microtubes10and 18.74 t/ha has been reported8. The yields of broccoli was reported11 to be 11.11 t/ha.
Table 3 Mean vegetative growth parameters under different irrigation treatments
Treatments | No. of Leaves | LAI | Plant Height, cm | Girth, cm | Branches/ Secondary Head, no | No. of Fruits | Root Length, cm | Yield per Plant, kg |
T1 | 140.60 | 2.46 | 26.80 | 11.31 | 9.20 | 10.20 | 29.00 | 1.01 |
T2 | 30.40 | 1.60 | 54.80 | 3.02 | 14.20 | 26.40 | 30.60 | 1.93 |
T3 | 53.60 | 2.08 | 64.40 | 4.59 | 15.40 | 27.80 | 32.20 | 2.19 |
T4 | 57.80 | 1.48 | 21.30 | 6.94 | 5.80 | 6.80 | 22.10 | 0.60 |
Treatments | Wet (residue) | Dry (residue) | Dry matter Content | |||||
Crop kg | AG Bio, kg | Root, kg | Crop, kg | Root, kg | Crop Residue, % | Root Residue, % | ||
T1 | 2.64 | 3.65 | 0.089 | 0.292 | 0.035 | 10.97 | 38.93 | |
T2 | 0.24 | 2.17 | 0.018 | 0.030 | 0.006 | 12.53 | 32.59 | |
T3 | 0.68 | 2.87 | 0.033 | 0.102 | 0.012 | 14.71 | 36.65 | |
T4 | 0.90 | 1.50 | 0.045 | 0.095 | 0.017 | 10.20 | 37.15 |
Note: LAI = Leaf Area Index; AG = Above Ground; Bio = Biomass
Water Use Efficiency (WUE) of irrigation system
The water use efficiency (WUE) is one of the best tools for evaluating the performance of different irrigation treatments. The WUE was calculated as the ratio of the crop yield (t/ha) to the total applied seasonal irrigation water (cm) during the crop growing season.
The WUE for each treatment combination is presented in Table 4. The seasonal water requirement was found to be 20.08, 19.68, 18.61 and 21.06 cm respectively for treatments T1, T2, T3 and T4 and corresponding WUE are 1.46, 2.85, 3.41 and 0.82 t/ha-cm. The overall efficiency of water use in the experiment was found to be high due to saving of water. Only a small portion of the area was irrigated by controlled amount of water and deep percolation and the evaporation losses were minimum. High efficiency of water use is extremely important for farmers in water scarce semi-arid areas. The WUE of tomato reported8 was 0.68 t/ha-cm for drip treatment. It was reported12 that WUE ranging from 18.7-6.52 kg/ha-mm for sprouting broccoli.
Table 4 Seasonal water requirement, water use efficiency of tomato and broccoli
Treatments | Average Yield, t/ha | Seasonal Water Requirement, cm | Water Use Efficiency, t/ha-cm | |||
Tomato | Broccoli | Tomato | Broccoli | Tomato | Broccoli | |
T1 | – | 29.27 | – | 20.08 | 1.46 | |
T2 | 56.03 | – | 19.68 | – | 2.85 | – |
T3 | 63.46 | – | 18.61 | – | 3.41 | – |
T4 | – | 17.33 | – | 21.06 | – | 0.82 |
Economics
Drip irrigation is suitable for vegetables and orchards but it gives maximum return for vegetables within a season. Cost is the major constraint in adoption of drip irrigation for small land holders. The economic analysis was done as per existing market situation and the data pertaining to each component, cost of production of broccoli and tomato, net return from different irrigation treatments. As the cost of materials fluctuates very fast, the economic analysis may change with time and place. The price of the product may also vary from place to place and from time to time which will affect the economic analysis significantly. The generalized form of economic analysis data are given in Table 5 for different treatments. In analysis of economics of systems 70 per cent subsidy was also considered.
Seasonal cost of component per hectare without and with 70 % subsidy was in T1 (Rs. 168149/ Rs. 50445) and T2 (Rs.168149/ Rs. 50445) followed by T3 (Rs. 46249/ Rs. 13875) and T4 (Rs. 46249/ Rs.13875) respectively. Seasonal cost of cultivation per hectare was in T2 (Rs. 54343) and T3 (Rs. 54343) followed by T1 (Rs. 51784) and T4 (Rs. 51784). Seasonal return from produce per hectare was in T3 (Rs. 634600) followed by T1 (Rs. 585380), T2 (Rs. 560342) and T4 (Rs. 346591) respectively. Net seasonal income without and with subsidy (70 %) per hectare was in T3 (Rs. 534008/ Rs. 566383) followed by T1 (Rs. 365447/ Rs. 483151), T2 (Rs. 337850/ Rs. 455554) and T4 (Rs. 248558/ Rs. 280933) respectively. The developed system has pay back period of one season only, benefit to cost (B/C) ratio varies from 1.52 to 5.31 without subsidy and 4.28 to 8.30 with subsidy.
Table 5 Benefit cost ratio of broccoli and tomato under different irrigation treatments in drip irrigation system
S. No. | Cost economics | LPLC drip irrigation system | |||||||
Broccoli | Tomato | ||||||||
Medi-emitters (T1) | Microtubes (T4) | Medi-emitters (T2) | Microtubes (T3) | ||||||
Without subsidy | With 70 % subsidy | Without subsidy | With 70 % subsidy | Without subsidy | With 70 % subsidy | Without subsidy | With 70 % subsidy | ||
1 | Fixed cost | 146217.0 | 43865.0 | 40217.0 | 12065.0 | 146217.0 | 43865.0 | 40217.0 | 12065.0 |
a | Depreciation | 13160.0 | 3948.0 | 3620.0 | 1086.0 | 13160.0 | 3948.0 | 3620.0 | 1086.0 |
b | Interest | 7311.0 | 2193.0 | 2011.0 | 603.0 | 7311.0 | 2193.0 | 2011.0 | 603.0 |
c | Repair and maintenance | 1462.0 | 439.0 | 402.0 | 121.0 | 1462.0 | 439.0 | 402.0 | 121.0 |
d | Total (1+a+b+c) | 168149.0 | 50445.0 | 46249.0 | 13875.0 | 168149.0 | 50445.0 | 46249.0 | 13875.0 |
2 | Cost of cultivation | 51784.0 | 51784.0 | 51784.0 | 51784.0 | 54343.0 | 54343.0 | 54343.0 | 54343.0 |
3 | Seasonal total cost (1d+2), Rs | 219933.0 | 102229.0 | 98033.0 | 65659.0 | 222492.0 | 104787.0 | 100592.0 | 68217.0 |
4 | Yield of produce, t/ha | 29.27 | 29.27 | 17.33 | 17.33 | 56.03 | 56.03 | 63.46 | 63.46 |
5 | Selling price, Rs/kg | 20.00 | 20.00 | 20.00 | 20.00 | 10.00 | 10.00 | 10.00 | 10.00 |
6 | Income from produce, (4×5), Rs | 585380.0 | 585380.0 | 346591.0 | 346591.0 | 560342.0 | 560342.0 | 634600.0 | 634600.0 |
7 | Net seasonal income, (6-3), Rs | 365447.0 | 483151.0 | 248558.0 | 280933.0 | 337850.0 | 455554.0 | 534008.0 | 566383.0 |
8 | Seasonal BC ratio, (7/3) | 1.66 | 4.73 | 2.54 | 4.28 | 1.52 | 4.35 | 5.31 | 8.30 |
Life of components = 5 years, Season considered = 2, Interest rate = 10 %,
Repair and maintenance cost = 2 % of total cost.
Since the payback period for all treatments is 1 season and B/C ratio is more than 1, even as high as 5.31 (without subsidy) in case of microtubes, this may be considered to be a viable option for small landholders.
It was reported10 that B/C ratio, 9.81 for drip microtubes in case of high yield tomato. The net return of Rs. 88601/ha with B/C ratio 3.99 from sprouting broccoli was reported11. Several researchers reported higher crop yield and more income from the produce besides saving of water through drip methods of irrigation14, 15, 16, 17 and 18.
It was reported1 that installation cost of micro-drip irrigation was Rs.78000/ha with B/C ratio 6.36 where as Rs. 100000/ha for lateral spacing of 1.8 m with cost of cultivation Rs. 67214 with B/C ratio 3.81 has been reported.
CONCLUSION FOR DRIP IRRIGATION SYSTEM (LPLC)
Treatments T1 and T3 performed better than T2 and T4 with respect to vegetative growth parameters. Microtubes performed better than medi-emitters. Daily drip irrigation maintained soil moisture near field capacity. As the payback period for all treatments is one season and benefit to cost (B/C) ratio is in the range of 1.52 to 5.31 without subsidy and 4.28 to 8.30 with subsidy, it can be presented an attractive prospect. Water efficient irrigation method (LPLC) drip irrigation system that is affordable, divisible and appropriate can significantly improve food production and the livelihoods in water scarce areas of developing countries, promoting greater economic and food security.
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