Comparing earthen channels with plastic piping for efficient and cost-effective irrigation

In the Eastern Gangetic Plains, many farmers have made many positive changes to irrigation practices. For example, farmers have started using diesel pumps and have adopted better water application practices such as using furrows. But, water conveyance to fields is often still through the use of earthen channels. For large plots of land, farmers have constructed permanent channels that connect different plots. Farmers working with small plots of land, often marginal and tenant farmers, use temporary earthen channels (mostly based on seasonal requirements).

Earthen channels, however, have some disadvantages. Earthen channels incur huge water losses and  lead to a reduction in the effective area available for crop cultivation. To convey water from water source to the fields, a flexible plastic pipe can be a better alternative to these earthen channels.

While working in the project villages for DSI4MTF, scientists and field staff have found that farmers cite the cost of conveyance plastic pipes as the major reason for not adopting plastic pipes for conveyance. To demonstrate the effectiveness and economic benefit of plastic pipes to farmers, DSI4MTF conducted a field experiment and economic comparison that assessed the benefits and costs of earthen channels and plastic piping.

Flow-rate at the end of the 100 m channel is taken with a V-notch weir.

Water loss assessment

During a recent field visit, engineers from the University of South Queensland (USQ), Australia and the International Water Management Institute (IWMI) measured the loss of irrigation of water through earthen channels. In Bhagwatipur, a project site of the DSI4MTF project, a straight 100m permanent earthen channel that begins at a water source was selected for the assessment. Scientists used a portable V-notch weir for measuring the flow of irrigation water in the earthen channel.

For this experiment, scientists and field staff first cleaned the 100m permanent earthen channel and properly sealed any leaks so that no loss of irrigation water could occur from rat and crab holes. After, scientists and staff inserted the calibrated V-notch at the end of 100-meter-long channel and properly sealed it from all sides. The earthen channel was filled up with water and was left for one hour until a steady state of flow was achieved. At this point, the flow rate of the solar pump water source was taken by using a 60 litre bucket and stopwatch and compared with the mechanical inline flowmeter reading. Simultaneously, the reading of the flow rate at the V-notch was taken. The difference in flow rate between the source and the V-notch weir at the 100 m point of the channel revealed the loss in irrigation water through the earthen channel.

The irrigation water loss through an earthen channel was finally compared with that of plastic conveyance pipe used by farmers. The result of conveyance losses through earthen channel as well as plastic conveyance piping is given in table-1.

Table-1: Percent loss of irrigation water through earthen channel and plastic pipe

Total loss through 100m of the earthen channel is 2.7 litre per second. Conveyance efficiency of water irrigation method is calculated by dividing the flowrate at the V-notch at the end of the 100 meter pipe by the flow rate of the water source. Thus, farmers lose 47% of total irrigation water through earthen channel.

Field staff seal the bottom and sides of the channel with plastic.

Economic comparison

To understand the cost difference between using earthen channels and plastic pipes, a cost comparison was carried out. Construction of earthen channels involves sacrificing productive land because land must be allocated for the channel itself. Irrigation pipes require no special land allocation. To carry out the economic comparison, labour required, area lost, and the life of the systems were compared. Earthen channels last for 5-10 years while plastic pipes last for 2 years (Table 2). For the sake of analysis, a 7 year life-span was assumed for permanent earthen channels.

Table 2: Costs associated with earthen channels and plastic pipes

Conclusion

After an analysis of experiment results, carrying out a cost comparison, and discussing with farmers about conveyance systems,  DSI4MTF staff have concluded that the water loss from earthen open channels is significant and the cost of the earthen open channel is higher than that of plastic pipes. Farmers must consider these costs and loss of water when choosing a water conveyance system for irrigation.

Training on ‘maintenance of Drip and Sprinkler systems’ conducted at Bhagwatipur

With the introduction of interventions on solar pumping, drip and sprinkler irrigation, the agricultural production systems in the project villages are getting intensified. New crops are introduced,  better irrigation schedules are adopted,  improved cultivation practices like raised bed with polythene mulch are practiced. However, the major challenge for the farmers was to maintain the drip and sprinkler irrigation system which they were experimenting for the first time in their life. It was important to train them on this aspect.

A training programme on operation and maintenance of the drip and sprinkler systems was conducted for the participating farmers, mostly women.  Initial discussions focued on cleanliness of the water sources like pond and tube well. Cleaning of filter screen (mesh) was first explained with live demonstrations and then tried by individual farmers of each collective. Flushing of sub main lines and laterals was discussed and demonstrated. In general, emitter clogging is major issue with drip system. Framers were trained on how to clean the choked emitters using simple tools and techniques.  The chemical treatments for biological (moss, algae, roots) and chemical (salt deposits) clogging of emitters were discussed in detail. Farmers were informed about the practices to prevent damage to system parts during field operations. Practices and availability of chemicals for safe gaurding the laterals from rats and rodents were also discussed. Finally, a live demonstration was conducted on how to fold, collect and store the laterals at a safe place during the off season. It was a very interactive training in which farmers asked several questions which were answered and discussed in detail.

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A training program-cum-exposure visit of Madhubani farmers to ICAR-RCER Ranchi

By Santosh Mali and Anoj Kumar

A field visit of DSI4MTF project farmers to ICAR-RCER Research Centre Ranchi was undertaken on 13th Aug 2016. Fourteen farmers including 6 women farmers from both the villages, Bhagwatipur and Mauahi, participated in the training program cum-exposure visit. This was one day visit in which farmers were given 3 hours of classroom training on vegetable cultivation practices and plant protection measure. The training was facilitated by scientists and technical persons from ICAR RCER Ranchi through three interactive sessions of one hour each. In Second half of the day, farmers were taken to experimental fields of ICAR where they got an opportunity to acquaint and understand the better techniques of vegetable cultivation including drip, sprinkler, mulching, vermi composting, shade net nursery production etc. After visit to on-station trials the farmers visited the fields of one of the progressive farmers of Devgain village of Ranchi district of Jahrkhand. The farmer is cultivating the vegetable crops with state-of-art technologies of crop production like drip system of irrigation, bicolour polythene mulching, fertigation with ventury and better nutrient management.

Participants

  1. 14 Farmers (6 women and 8 men)
  2. Ritesh Kumar (Sakhi)
  3. Neetu Singh(Sakhi)
  4. Rajesh Kumar(Sakhi)
  5. Ritesh Ojha(Field Assistant ICAR)
  6. Omkar Kumar(Field Assistant ICAR)
  7. Fraser Sugden(IWMI)
  8. Santosh Mali(ICAR)
  9. Anoj Kumar Kumar(IWMI)

Why Selected Ranchi for field visit?

  1. Many farmers of Ranchi have already adopted drip, plastic mulch and other best agronomical practices for vegetable cultivation. The purpose was to help our project farmers through their experiences.
  2. The objective was to learn how farmers of Ranchi have overcome the problem of water scarcity during the dry season.
  3. Farmers exposure to intensive vegetable cultivation practice and use of biological and organic pest and disease control
  4. Many tribal and other socially backward farmers of Ranchi have adopted improved vegetable cultivation practices which can be a good learning example for our farmers.

In house training on agronomical practices by ICAR Scientist

This session was taken by three scientist from three different discipline one from horticulture division, one from pathology division, and one from entomology division.

  1. Vijay Kumar Singh, Senior Technical Officer, ICAR RCER Ranchi covered the ground on general practices of vegetable cultivation starting from field selection for vegetable cultivation till harvesting all practices. Selection of crop, selection of seed, use of fertilizer and irrigation practices. Many farmers ask their query to the scientist and get their answer. Vegetable cultivation on large scale was stressed upon through a general economic analysis of tomato cultivation. Also Off-season cultivation of vegetables through low tunnels and staggering the dates of sowing/planting was discussed as a better option to fetch higher price in the markets. The sowing times and improved varieties of different vegetables was also discussed during the interactions with the farmers. This was very useful session to farmers.
  1. Pathology scientist (Dr Sudarshan Maurya, Senior Scientist, ICAR RCER Ranchi) discussed the general and particular diseases of vegetable in different seasons and their control measures. During this session scientist covered the aspects of selection of disease free seed and planting material, preventive measure for disease appearance and control measure. Seed treatment and management of tomato and Brinjal wilt was discussed. He also showcased the packets and pouches of the effective and commonly available fungicides in the market. During this session farmers asked many questions and got a satisfying reply from the scientist.
  1. Entomology Scientist (Dr. Jaipal Singh Chaudhary, Scientist, ICAR RCER Ranchi) discussed the insect pest infestation of different vegetable crop grown by our farmers during last summer season and current vegetable crop (Brinjal). He shown the video of life cycle of insect pest and explained the most harmful stages of the insects that needs immediate control. For controlling the damage of crop farmers should know which stage of life cycle of insect pest can be controlled to bring down the pest population below the economic threshold level. He also discussed the biological control of pest in brinjal and Okra crops. In brinjal crop, if farmers grow maize as border crop, then insect pest gets attracted to maize flower and farmers need to apply pesticide on maize flower only. Thus farmer can prevent the potential damage that a pest can cause. He also talked about growing of coriander crop in between brinjal crop can reduce the insect pest infestation and farmers can take additional income from coriander leaf. He also talked about use of pheromone trap for different crop to control insect pest population. Another low cost technique like use of jaggery (Gur) and nuvan to control the insect pest population.

Field training and field visit

Farmers were taken to the experimental fields of ICAR RCER by Mr. Chandrakant Gupta, Senior Technical Officer, ICAR, RCER, Ranchi who demonstrated the drip & Sprinkler irrigation technology, mulching and raising of nursery in portray and different variety/cultivar of vegetable and fruit crop. He also exposed the farmers to a vermicomposting unit. He explained the utility and benefits of these technologies to the farmers and answered the queries raised by the farmers.

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Mr Anoj, Dr Frazer and Farmers heading for field visit

Visit to the farms of a progressive farmer

After the detailed discussions on the technologies demonstrated at ICAR-RCER, Dr. Santosh Mali led the farmers to visit the farms of one of the progressive farmers Mr. Shivcharan Kachhap of Devgain village of Ranchi district. This farmer practiced rice-follow system for years with low net returns and had difficulty in sustaining his livelihood. During last 2 years he has started growing multiple crops in year through adoption of drip irrigation system, plastic mulching and intensive farming of vegetable crop. With the experiences he learned from the drip irrigation that he practiced from a small scale drip irrigated plot, he has now increased the area under drip irrigation system to 3.5 acre. This has increased his income by many folds. Inspired by his success, many farmers in the adjoining areas have followed the suit. Mr. Shivcharan Kachhap shared his experiences on how he started the vegetable cultivation practices and use of drip and plastic mulching for water conservation and taking best crop of vegetable. He also showcased a nursery of vegetable crop where he is growing nursery in portray which allows early planting of vegetable crop to fetch the good price of their produce. He also discussed in detail the marketing mechanism of vegetable produce. Mr. Shivcharan Kachhap presently has the standing crop of Chilli, Tomato, Bitter guard (late stage crop), other minor vegetable crop and a healthy nursery of cucumber. Mr. Shivcharan also shared his experiences on cash and kind benefits from different crops he is earning through adoption of improved vegetable cultivation practices. The bitter gourd was cultivated in rows of trellis with a staking support of a bamboo and nylon thread. He explained the farmers about the total cost involved in bitter guard cultivation and net income he earned from the cultivation of one acre of bitter crop on trellis. This was very motivating aspect to our farmers. He also shown the yellow sticky paper for insect control in chilli field. He also demonstrated the farmers the fertigation process through drip irrigation system. Ventury system of fertilizer application was much appreciated by the farmers, particularly the response of women farmers was overwhelming.

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Farmers interacting with Mr Shivcharan Kachhap of Devgain Village

Acknowledgements:

It was a great team effort. Mr Ritesh Kumar and Sakhi team making the travel arrangements for the farmers. Mr Anoj Kumar (IWMI) looked after the needs of the farmers during the journey and ensured safe travel during the 16 hrs of 550 km long journey. Dr Santosh Mali (ICAR-RCER, RC Ranchi) arranged all logistics for the stay at Ranchi, organised a training program in his office premises successfully and co-ordinated a visit to farmer’s field. The interactions with Dr Frazer Sugden (IWMI) during the training and field visits were useful in further planning and implementation of the project.

 

Wheat irrigation in Gangetic plains of Bihar – It’s time for a change

bihar

Rice-wheat cropping system dominates the agriculture in the Gangetic Plains of the North Bihar. Rice is cultivated during the kharif (monsoon) season with transplanting dates matching with onset of monsoon. Sufficient monsoon rainfall generally precludes the need of irrigation for this crop, except in the event of dry spell. Wheat, which is the main rabi (winter) crop of the region, requires at least three irrigations during the critical stages of the plant growth to make wheat cultivation profitable.

A field survey revealed that a 4 or 5 hp diesel pump set, which is most common in the region, is used to pump water from tube wells. Water is conveyed from the source to fields using either flexible polyethylene pipes or, in few cases, using field channels. Fields usually do not have intra field water distribution channels and water is delivered at the corner of the bunded field or at some point in the field, which farmer feels, will be appropriate to distribute water to entire field (flood method of irrigation). The cloddy and uneven fields in combination with closely spaced wheat stems offer lot of resistance to the waterfront, slowing down its rate of advance. During the course of the irrigation, water delivery point in the field is shifted to other desirable locations depending on the depth of the standing water and area covered by the current delivery location. Before changing the delivery point, farmer ensures that sufficient depth of water is applied at the farthest point from the present point of delivery. This eventually requires sufficiently longer irrigation events so that water reaches the farthest end, resulting in huge deep percolation loss in the vicinity of the delivery point. The deep percolation losses, combined with losses from faulty connections and punctured conveyance pipes incur an extra expenditure on irrigation.

 

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Wheat field Water delivery the wheat field
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Leakages in conveyance pipes

Ground water is the major source for wheat irrigation and farmers are purchasing it at the rate of Rs. 120 per hour. Farmers informed that it takes about 10 to 12 hrs for a 5 hp diesel pump to irrigate an acre of a wheat field. Many farmers afford only two to three irrigations for a wheat crop and pay Rs. 2400 to 3600 to the tube well owner. Interviewed farmers reported an average wheat yield of 10 quintal per acre which provides a gross return of about Rs. 10000 per acre. This indicates that irrigation takes away 24 to 36 % of the gross return depending on the number of irrigations applied. It is important to reduce the water losses and consequently the expenditure on irrigation so that farmers can afford more number of irrigations and get improved wheat yields. Adoption of efficient irrigation systems like ‘sprinkler irrigation’ can help in achieving these twin objectives. Apart from reduced deep percolation losses and uniform water application, sprinkler system offers better control over the available water flow. Farmers, mostly tenants and women farmers cultivating the wheat crops in the region, need to be informed about the sprinkler irrigation systems. It’s the high time that we demonstrate the applicability and potential of sprinkler irrigation for wheat cultivation.