Case Studies

Integrated pest management for African vegetable crops

Vegetable growing for local and export markets is a profitable occupation for many smallholder farmers throughout Africa. Currently, most farmers rely on the use (and often misuse) of synthetic pesticides to control pests. At the International Centre of Insect Physiology and Ecology (ICIPE), based in Nairobi Kenya, researchers are developing and demonstrating safer alternatives.

During surveys in the four countries, well over 200 collections of native egg parasitoids were assembled and are now being studied with the aim of identifying promising species with potential for mass production and commercialization. The project has supported a private company in the establishment of commercial mass production in Kenya.

The red spider mite (RSM), Tetranychus evansi, is a serious pest of tomatoes, at times causing yield reductions of up to 90 percent. It originates from South America and was probably introduced into southern Africa in the1970s, from where it has spread into many countries of sub-Saharan Africa. The project is developing integrated pest management (IPM) strategies to control the mite, concentrating on three major areas: classical biological control, resistance of tomatoes to RSM and cultural control measures.

A number of natural enemies, mainly predatory mites, have been identified in northeastern Brazil, an area with comparable climatic conditions to eastern and southern Africa. These predators are currently being studied to identify species suitable for introduction into Africa. The project is also screening for resistance in commercial tomato varieties and wild relatives of the cultivated tomato and the mechanisms of resistance are being investigated. It is planned to incorporate the resistance genes into commercial varieties through a breeding programme.

Cultural measures such as pruning and staking can reduce mite infestation and increase yield and quality of tomatoes. This is partly a result of better mite control (it is easier to reach the mites with acaricides on pruned and staked tomatoes) and partly to plant physiological factors. Farmers in Zimbabwe have already adopted these practices after seeing the benefits in on-farm trials.

Diamond-back moth
Among the worst pests of vegetables on a world-wide scale is the diamond-back moth (DBM), Plutella xylostylla. It is a prominent pest of brassica crops throughout the tropics and also in more temperate climates. DBM has become notorious for developing resistance against all classes of pesticides. ICIPE is leading a regional effort to improve the biological control of this pest in eastern Africa. After studies on locally occurring natural enemies and their impact on DBM populations, an exotic parasitoid, Diadegma semiclausum, was introduced from the Asian Vegetable Research and Development Centre in Taiwan.

The parasitoid has been released in three pilot areas in Kenya and one in Tanzania. Impact monitoring is on-going and parasitisation rates at the earliest release site have surpassed 45 per-cent. Diamondback moth populations have declined when compared to the pre-release situation, but it is too early for a final assessment. Large-scale releases of this parasitoid are planned for Kenya, Tanzania and Uganda and later for Ethiopia and other countries in the region. Introduction and releases of complementary parasitoids attacking different stages of DBM and with adaptation for hotter climates are planned for a second phase of the project.

Farmers, on an IPM training course in the Keiyo Valley of Kenya, look through a crop of French beans

A larval (Cotesia plutellae) and apupal parasitoid (Diadromus collaris) are under consideration. A series of tests with C. plutellae from different sources have already been initiated and the first field release will be made later this year in collaboration with colleagues of the National Agricultural Research Organisation in Uganda.

Smallholders are producing the bulkof export vegetables from Kenya. They have been hard-pressed to comply with requirements of the markets, especially those on maximum pesticide residue limits (MRLs) and issues of hygiene during all stages of production and transportation. ICIPE is a leader in a project to prepare smallholder growers in Kenya to produce export vegetables in compliance with EU requirements. The project focuses on· French beans and okra, both major export vegetables in Kenya.

Training of trainers in French beans IPM has been conducted and currently farmer group training by the graduate trainers is proceeding in the major French beans-producing districts of Kenya. A knowledge-attitude-practice survey of okra smallholder producers has been conducted and field studies for development of MRL-compliant IPM production have been initiated. A training programme for farmer group training has been developed, and back-stopping of the group training activities and impact assessment is built into the project.

Dissemination of results
Even though ICIPE is basically a research institution, capacity building and farmer training are built into all projects. As ICIPE does not have the necessary capacity to do large-scale extension work, the Centre is working through national agricultural research and extension services (NARES) with farmers in Ethiopia, Uganda, Tanzania and Kenya.

In general, ICIPE's role is limited to developing activities for training of trainers, training materials and giving support to the trainers during farmer group training. In this respect, a Technology Transfer and Training Unit has been established. In the medium-and long term, it is intended to channel most of the technology transfer activities through this Unit.

In the area of horticultural production, three IPM manuals have been developed, for French beans, crucifers and tomatoes; a manual for okra production should be available before the end of this year.

For more information contact Dr B. Lohr ICIPE, P.O. Box 30772, Nairobi, Kenya.
E-mail: blohr@icipe.org   website: www.icipe.org

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Let the poor manage their groundwater

Government subsidies have also kept pump prices inflated by more than 35-45 per cent com-pared to neighbouring Pakistan and Bangladesh.

In Uttar Pradesh and north Bihar, however, where the pump subsidy and loan programmes have been released from the stranglehold of the local bureaucracy, the results have been encouraging - estimates show 800,000small diesel pump operated tube wells have been installed in eastern Uttar Pradesh since 1985, irrigating around2.4 to 3.2 million hectares.

Here, market mechanisms have been used to manage the pump subsidy and loan programmes for the poor. In towns, there has been a proliferation of private dealers, who as a result of intense competition, have begun to offer farmers a range of useful services that were never offered previously -including the organisation of bank loans, the issuing of pipes and pumps, and the drilling of boreholes. 

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Green gold: commercial organic cotton

In 1985 we lost all our cotton to white fly. It was an insect we had never even heard of before. Our losses made us think and when we analyzed the reasons, obviously the rampant use of pesticides was the cause. Yields had come down to 2-2.5quintals/acre from an average of 6q/acre."

"We knew the answer was not to use chemicals. At that time we had no options, not a single university could help us and even the Central Institute for Cotton Research (CICR), Nagpur, was unable to give us any advice." Then Subedar met one of the pioneers of non-chemical farming, Bharat Dabholkar, and he was instrumental in changing his farming practices.

Subedar farms 260 acres, growing sugarcane, banana and lentils as well as cotton. He grows several varieties of cotton to select the best. "I found that high yields have no relationship with chemicals or fertilisers - we can prove that on our field. The other trick is to get a suitable variety of crop - we want an indeterminate type. And the third factor affecting yield is the distance between two rows and two plants. There must be room for cotton to grow."

In 2002, he planted 1X varieties of cotton on 45 acres, of which 35 acres is rain-fed. He stopped using chemicals in 1990, and it has taken five years to stabilize the yield. He mixes 30 kg cow dung, 30 litres cow urine, 300 litres of water with black jaggery and ferments it for five days. This solution is diluted 20 times and sprayed on the field. Last year yields were 8 q/acre

The use of chemicals and pesticides is very high in this district and five years ago Rs 100 crore was spent in this district alone. Now spraying is considerably reduced and local farmers and dealers estimate the amount spent has come down to Rs 40 crore.

Subedar's expenses for cotton area bout Rs 4,000 per acre; it was double that when he was using chemicals. Large landowners and rich farmers can spend up to Rs 12-14,000 on chemicals and pesticides with about 20 sprays in one season. Subedar and other large farmers like Om Prakash Mor and Baburao Wankhede have inspired scores of farmers to stop using chemicals in this region.

Marketing

Mehta's efforts and those of the farmers and later of CICR laid the foundation for growing cotton organically and exporting it. Mehta records that meetings resulted in 135 farmers committing 1,200 hectares of land to organic cotton by June 1995. Then 132 farmers formed the Vidarbha Organic Farmers Association (VOFA) to market cotton on a non-profit basis. Agreco agreed to certify the farmers and in1996 they grew a bumper crop of organic cotton.

"We had prepared a complete 70-page booklet for farmers who were interested in organic cotton cultivation," said Kisan Mehta. "The cotton was grown under international organic standards certification guidelines and the German support ensured certification and other requirements. Over 1,200hectares were soon under organic farming, making it (then) the largest area in the world under such cultivation."

Subedar adds, "We want to promote organic crops and we feel farmers should get a good price. Cotton is being exported since 1995 and we sell 1,500-2,000 quintals every year." VOFA has paid its members Rs 51 lakh since1995-96, and in 2002 they got a bonus of Rs 700 per quintal. It is also making efforts to sell other organic produce from this year.

For organic farmers like Raosaheb Dagadkar, exporting organic cotton is the only reason to grow it. A member of VOFA, he is a certified organic cotton farmer. Visiting his farm it can appear very untidy. Weeds grow everywhere and there is barely any space between two plants. "Fully-grown cotton fields become like a forest - I can't enter," he joked. He adds that weeds are a gold-mine and he uses them to mulch his land. "I find compost expensive so I use what is there in nature. All we need to do is create conditions for earthworms to grow and then there is no need for bullocks or ploughing." Raosaheb Dagadkar says his cotton yields about4-6 quintals per acre.

Organic cotton in Madhya Pradesh
Maikaal bioIie Ltd, in Madhya Pradesh, claims to be the largest organic cotton venture in the world. It has over 1,000farmers on 7,600 acres involved inorganic cotton production. It started in1991 as a private initiative of Mrigendra Jalan, Managing Director of the spinning mill, Maikaal Fibres Ltd,and Patrick Hohmann, Managing Director of the Swiss cotton yam trading company, Remei AG.

In Kogawa village in Khargone district, Sher Singh grows cotton on 8.5 of his 10.5 acres. He is a member of Maikaal and a certified organic farmer for the last four years. He also grows tuvar, makai (maize) and mung. His cost of chemicals and pesticides have fallen from Rs 2,500-3,000 per acre toRs 1,300 per acre.

After switching to organic farming, Singh found that yields halved to 12 q from 8 acres, but in the second year he harvested 16 q from 8 acres. He feels things will be better this year. Farmers with Maikaal now believe that pests are fewer and expenses less.

Organic farmers get a premium of 10-20 percent above market rates. However, price need not be the only incentive for organic farming. The importance of organic farming in regions like Vidarbha which is marked by poverty and drought, cannot be over-stressed. Every year many farmers commit suicide in this region and NGOs like Dhara Mitra and YUVA are trying to promote organic farming among small farmers in a bid to reduce their cost of cultivation. It is not only for that extra premium that farmers must adopt organic farming - in some cases it may save their lives.

This is abridged from a longer article published by Infochange on its website:
www.infochangeindia.org. For more information contact Meena Menon. E-mail: cats@,bol.net.in

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It is well known that the ground water in many coastal and inland areas is brackish and not potable. Many areas are remote and without electricity to operate a desalination plant. So there is a need for appropriate desalination technology, and this has been developed by the Central Salt & Marine Chemicals Research Institute (CSMCRI), in India. 

Desalination is not difficult using the reverse osmosis process but it needs power to force water through the membrane against osmotic pressure. Many villages don't have electricity so another form of power is needed. During non- agricultural periods such as summer months, when the need for water is especially acute, many villages have spare work oxen, so the idea was borne to use oxen as the source of power.  

The idea was conceived by Dr. Pushpito K. Ghosh, Director of CSM- CRI, and subsequently designed by Mr. Nagendra Pathak and his team has developed such a unit.  

A pair of bulls is connected to one end of a four metre long metal shaft while the other end is coupled to a gear box, comprising three sets of bevel helical gears. The gear box is designed to convert bullock power into mechanical power as the oxen walk slowly round in a circle. The output shaft from the gear- box is coupled to the crankshaft of a reciprocating high pressure pump, which discharges 20 litres of water per minute at 22-25 bar hydraulic pressure. This hydraulic pressure is adequate to carry out desalination and deliver 350 -500 litres of water per hour. The plant reduces water containing 3000 -5000 mg/l total dissolved solids down to less than 500 mg/l TDS. Bacteria and other harmful elements such as fluoride, arsenic, nitrate and heavy metals are also removed through the reverse osmosis desalination process.  

The cost of the prototype unit is Rs. 250,000 (£3500), excluding animal cost and cost of site development. The cost is likely to go down on large scale com- mercialisation. The operating cost is about Rs 7-10 (£0.10) per 100 litres of drinking water, inclusive of cost of man- power in India to operate the unit.  

The system can produce enough water to cater for the cooking and drinking water needs of 1000 villagers when the unit is operated for 8 hours per day. The Institute is undertaking further research and development to improve the performance, robustness and capacity of the unit. It is also attempting to modify the system for seawater desalination.  

The Institute has found that one pair of oxen can work for two hours before they need a 30 minute break. Dr Ghosh says in this manner they can continue for six hours comfortably. "If we want to operate continuously and for longer hours, we will require two pairs of oxen. I should add that the oxen need to be reasonably well built and sturdy. One more point to note is that they get better at their job with practice, especially since the motion involved is circular. Initially, they tend to pose some resistance."  

More information from Dr. P. K. Ghosh, the Central Salt & Marine Chemicals Research Institute, Bhavnaga1; 364002 Gujarat, India. E- mail: pkghosh@csir.res.in

Reproduced from Appropriate Technology (Volume 30/ issue 3 (2003), page 23) with permission from Research Information Ltd.
Website: www.appropriatechnology.com

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An improved and more efficient rickshaw has been making life easier for Indian operators for several years.  Now the same concepts being tried with the Indonesian becak.  Veronika Utz , GATE/Small-Scale Project Fund (SSPF), and Lisa Peterson, Institute for Transportation and Development Policy (ITDP), report how the technology is being transferred to Indonesia with the help of GATE's Small-Scale Project Fund.

Using the technology that helped to improve the Indian rickshaw, Indonesian drivers can look forward to a becak that is much easier to use. It is hoped the strain on them will be reduced by 40 percent, which means the drivers will be able to earn more money -as much as 20-50 percent more.  

The traditional Indonesian becak and the Indian cycle rickshaw are somewhat different. In the Indian vehicle, the passengers sit behind the driver, facing forward. In the becak, the passengers face forward, sitting in front of the driver. Both vehicle designs have remained substantially the same for over 50 years. Both are very heavy, have no gears, and are not designed with consideration for the ergonomics of the driver.  

In the late 1 990's, ITDP, which pro- motes environmentally sustainable transportation systems, began work with local NGOs in Agra, India. The aim was to design and disseminate a modem human powered rickshaw. This project put together a team of engineers from India and US to redesign the Indian cycle rickshaw to make it much lighter, have multiple gears, and superi- or passenger comfort but at a cost roughly the same as the current vehicle. This redesign effort was successful. To date, about 12,000 modem cycle rickshaws manufactured by over 20 small businesses have been sold in seven Indian cities.  (See 'Appropriate Technology - June 2002).  

From India to Indonesia  

After hearing about India's success in modernizing their cycle rickshaw, an Indonesian team from Gadjah Mada University (GMU) and the Municipality of Yogyakarta requested support for its own rickshaw modernisation programme. They wanted to reduce dependence on motor transport while preserving a place for the becak in traditional Javanese culture.  

Like many developing cities, Yogyakarta suffers from increased air pollution and noise problems associated with rapid motorisation. The growing use of private cars and motorcycles threatens the tourist economy and has begun to degrade the quality of life. The cycle rickshaw, or becak, is a cost- effective and non-polluting form of transport, and is a cultural icon for the city. Increasing numbers of national and international tourists equate the becak with the cultural richness of Yogyakarta. The city is a cultural centre of Central Java and a magnet for tourists.  

While some cities have begun to ban cycle rickshaws, the becak has received support from the Sultan and that has reduced the threat from traffic planners and police in Yogyakarta. Becaks continue to flourish, particularly in the city's narrow streets. Recently, a mayoral decree changed the status of becaks from informal to formal trans- portation. Becak drivers have good relations with the tourist industry and are included in major plans, supported by the Swiss Development Corporation, to create a non-motorised zone in the city centre. This situation created the perfect condition for a becak modernisation project, with the potential to spread to other Indonesian cities.  

South-South technology transfer  

The Indian cycle rickshaw uses a mass produced heavy duty bicycle for the front end, which is bolted onto an angleiron chassis. A hand-crafted wooden seat is bolted onto this chassis at small assembly shops. The whole thing weighs about 80kg. The seat is not comfortable, the canopy rarely offers protection from sun and rain, and the seat structure wears out in two to five years.  

The Indonesian becak, by contrast, is entirely made in small shops, using only mass-produced wheels and some components from a normal bicycle. The frame is made out of sturdy pipe, and the seat is made out of wood, steel drum, and steel filigree. The iron and wood chair and chassis are so strong that the vehicle lasts more than ten years, with replacement only of the wheels, tires and brakes. The traditional becak is much more comfortable than a traditional cycle rickshaw, but it is much heavier, around 100kg, and very hard to steer.  

In India, the ITDP and Indian technical team developed over ten proto- types, constantly refining the vehicle in response to comments from the drivers, the passengers, experts, and the manufacturers. The final prototype reduced the weight of the traditional vehicle by more than 30 percent, to 55 kg. This was done by replacing the angle-iron chassis and traditional bicycle frame with a single, integral tubular frame designed specifically for rickshaws, and by replacing the heavy wooden seat with a light, tubular seat and permanent canopy. While a gear system was developed, it was not popular. Ultimately, the modem vehicle succeeded commercially not because it was lighter but because it was more comfortable for the passengers and cost less to make than the traditional vehicle.  

G. Shyam, the lead Indian engineer involved in the Indian rickshaw project, was sent to Yogyakarta to collaborate with engineers from GMU and design the modem becak. Six different proto- types were developed. The experience from India shortened the prototype development phase, making it much less expensive, and cutting development costs by 75 percent -from $200,000 to $50,000 -to reach the same stage of the project. After one prototype was selected as the most likely to be commercially successful, phase two of the project began.

Financial contribution of GTZ/GATE/SSPF  

Funds for the second phase had been requested from GATE's Small-Scale Project Fund of the German Development Corporation GTZ. ITDP was a contractor to GTZ's Sustainable Urban Transport Project in Surabaya when they prepared a pilot non- motorised transport improvement project under Manfred Breithaupt and Karl Fjellstrom. As a result of their work traffic planners were convinced that an improved cycle rickshaw could be part of a modem traffic system. Local busi- ness leaders also agreed with this idea.  For this reason, ITDP decided to implement this project, with the proviso that GATE's SSPF provided the risk capital for the modifications of the traditional becak.  

For its part SSPF wanted the technology to be innovative. It had to improve the living conditions of the poor; be easily disseminated; include contributions from the target group and executing agency; and protect the environment. All these pre-conditions for support were given and justified the approval of the proposal. With this relative low financial contribution the project was able to continue.  

A fleet of 20 prototype vehicles were produced, and leased to becak drivers allover Yogyakarta for testing. This led to some modifications being made, and before it is commercialised it is likely that more modifications will be included in the future design.

The improved becak will have a light-weight tubular seat, like the redesigned rickshaw. The frame will be made of lighter materials than wood. Already, these measures have reduced the weight of the prototype by nearly 45 percent, from 100 kg to 55 kg. Fitting gears to the becak will be easy because they attach to a standard rear-bicycle wheel better rather than to a rickshaw axle. A standard, off-the-shelf derailleur from Shimano is likely be used.

Cultural acceptance

In the design process cultural preferences were always considered. For instance, all Indian cycle rickshaw wallahs believe that tilting the seat forward makes the vehicle easier to pedal and the passenger is less likely to fall back- wards, despite the fact that it is uncomfortable. While our field tests and engineers told us that this could not possibly make any difference, nonetheless, to find commercial acceptability, the private manufacturers have added a wood- en wedge under the tubular seat to make the seat tilt forward.  

One of the prototypes tested in Yogyakarta was the improved Indian cycle rickshaw, with the driver in the front of the vehicle and the passenger facing forward. While members of the hotel and tourism industry liked the Indian design, with passengers behind the driver, the becak drivers did not. They thought passengers would be uncomfortable seeing the driver pedalling hard in front of them, and that they would prefer an unobstructed view. They also felt it was rude for the passengers if they had to look at their backsides. Several felt it would be difficult to talk to the passengers, a critical part of the tourist experience. For these reasons, the design team decided to stick with the traditional Indonesian configuration with the driver at the back.  

When the fleet of the first 20 vehicles was road tested, more cultural problems arose. For example, the modem design had changed the steering so that it was much easier to use, but the drivers didn't like it as they felt they had no control. The drivers were also used to vehicles having a rigid spring under the carriage. They believed it provided suspension and made the vehicle easier to steer, more stable, and that gave the customers a smoother ride. Our engineering team insists that this spring doesn't provide any suspension, and field tests have indicated no real advantage in the steering. Customers, though, have been adamant about its importance, and so the spring will be put back into the design even though it will add considerably more weight.  

Economic efficiency

The key benefits of the new design are that it increases profitability; and is less tiring for the drivers allowing them to work longer each day without affecting their health. Surveys done in India have shown that drivers can ply the modem rickshaws a third longer than traditional vehicles.  

Because passenger comfort and safety are better, rickshaws have become a more popular form of transport. Passengers are also willing to pay more for a better ride. In India, higher fares, more riders and the ability to serve more customers in a day have increased profits by 60 percent for the average rickshaw driver.  

In addition to increased profits, the cost of a new vehicle is comparable to that of the traditional rickshaw, with price increases from 0-5 percent. The modem vehicles last up to three times longer than the traditional design and require much less maintenance and repair. Similar increases in driver efficiency and profits are expected for the becak once the final design is ready for market. 

Dissemination Involving the drivers throughout in the design process not only assured cultural acceptance, but meant there were a group of operators ready to start using the modem becaks in Yogyakarta. Once the design is finalised, a Muslim charity organisation plans to purchase more than 500 modem becaks. Hotels have also expressed interest in purchasing fleets of the modem vehicles to trans- port tourists. Public events, press coverage and industry support will also combine to reach a larger market with the modem becak With public policies that support the use of becaks, a community of willing operators and buyers, and a culturally appropriate design,  Yogyakarta's modemisation programme is likely to enjoy success.  

For more information contact  

Veronika Utz, GTZ/GATE, Postfach 5180, 65760 Eschborn, Germany, email: veronika.utz@gtz.de , web site: http://www.gtz.de/gate

 and

 Lisa Peterson, ITDP, West 30th Street, Suite 1205. New York, NY 10001, USA. email: lpeterson@itdp.org, web site: www.itdp.org

Reproduced from Appropriate Technology (Volume 30/ issue 3 (2003), pages 46-48) with permission from Research Information Ltd.
Website: www.appropriatechnology.com

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Groundwater declines: looking for the right solutions

With growing populations, changing weather patterns, and increasing pollution of surface water bodies, countries across the world are relying more and more on finite groundwater reserves built up over centuries, for household, agricultural, and industrial needs. Although addressing water shortages in the short term, groundwater exploitation brings with it its own host of problems. It can cause salt water intrusion into fresh water aquifers and subsidence of the land surface.

Governments are quick to turn to improving water efficiency as the best solution to the problem, but are too often disappointed. Research is increasingly highlighting that in devising water management strategies to conserve water and halt the decline of groundwater levels, policymakers

Heavy use of groundwater leading to steady declines in water tables is a problem increasingly witnessed in many parts of the world. In an attempt to reverse this trend, water policy experts and resource managers often advocate improving irrigation efficiency, an apparent solution that is also seen as being politically palatable. Such approaches, however, are not always effective. A holistic study of a hydrologic system is needed to find out how best to deal with groundwater depletion—what the optimal solutions are.

must conduct holistic studies of hydrologic systems to find appropriate solutions that will result in real water savings. What’s needed then is not a simple ‘one size fits all’ policy or solution, but varying management approaches to suit specific situations.

The concept of hydronomic zones, which categorizes a hydrologic system into different zones—each having its own water-related issues—could be a useful tool in this exercise.

Examining contradictions in the North China Plain

The North China Plain is China’s most important agricultural centre, producing more than half the country’s wheat and a third of its maize. Here, the deficit between rainfall and crop requirements has been met by irrigation from aquifers underlying the plain. Pumping water from the aquifers has led to the continued decline of groundwater levels despite improved irrigation efficiency and reduced pumping.

The North China Plain is 320,000 kmin extent and is home to more than 200 million people. It is bordered by mountains on the west and the Yellow Sea on the east. Three rivers drain into the plain (fig.1). The climate is temperate and monsoonal, with cold, dry winters and hot, humid summers. The plain is China’s most important centre of agricultural production, producing more than half the country’s wheat and a third of its maize. Yet, the shortage and seasonal distribution of water are two key factors that inhibit agriculture. Annual rainfall averages between 500 mm in the north and 800 mm in the south. The typical winter wheat/summer maize cropping pattern which is currently practised consumes 660mm to 920mm of water annually.

Figure 1:Location of Luancheng Country within the North China Plain

This seeming contradiction has puzzled water policy experts and resource managers and provided the impetus for IWMI’s study in the Luancheng County located in the Hai River basin, one of the three rivers making up the North China Plain (fig.1). The study examined the nexus between agricultural policies in the area, water management approaches, and actual water use, in an effort to explain the steady decline in groundwater levels and to find appropriate solutions to halt this decline.

 

Agricultural policies and water management in the North China Plain 1949 – 2000

Agricultural policies and related water resource development policies have undergone four distinct phases in the Luancheng County since the formation of the People’s Republic of China in 1949. The central goal of agricultural policy—food self–sufficiency—has however remained constant throughout these four phases. And going hand in hand with this policy is the requirement for a stable or increasing supply of water for irrigation.

Before 1949 there was no major irrigation development and most of the crops were rainfed. Only one crop per year could be produced. The area’s aquifers were recharged by seepage from three river channels, and there was also periodic flooding. During the Nation Rebuilding phase (1949 – 1958) much effort was put into irrigation works and this cut all stream flows into Luancheng except for the wastewater from Shijiazhuang City. Thus, ironically, the development of irrigation systems left the county drier than before.

In the Commune Era from 1958 to 1978, groundwater irrigation began in earnest and led to improved crop yields and continuous cropping with two harvests each year. Even at this early stage, declines in the water table were evident.

In the Early Reform period (1979 – 1984), production which until then had been managed collectively, was decollectivized. This had two significant impacts. Firstly, farmers had an incentive to work more efficiently, and an immediate increase in grain production was seen. Secondly, irrigation

Figure 2. Cropping history of Luancheng Country, 1949-1999— winter wheat sown area

efficiency improved.Groundwaterpumping for irrigation in Luancheng county decreased from about 1,020 mm/year in 1976 to about 390 mm/year in 1996.

Nevertheless, water table declines continued and concerned regional authorities formulated regulations to strengthen groundwater management. However, these measures were not implemented at local level. On the contrary, subsidies were provided for the construction of wells, facilitating an expansion in winter wheat production (fig. 2) and a shift from the relatively drought resistant cotton to irrigated maize (fig. 3).

The Later Reform period (1985 – 2000) saw an increasing demand for irrigation-intensive cash crops. There was also increased competition with the city for groundwater resources. Shijiazhuang city depends largely on groundwater, and increased pumping means that water that would naturally have flowed down to the aquifers underlying the Luancheng County is diverted for use by the city. Residents have had little choice but to dig deeper wells in search for water.

The effect: water use trends and groundwater declines: looking for the right solutions

As agricultural policies and water management strategies evolved over the years, water use trends also changed accordingly. With increased winter wheat cropping and a shift from cotton to more irrigationintensive maize, an increase in groundwater use that would mirror the cropping patterns could be expected. However, the reality is quite different. Contrary to expectations, groundwater pumping did not increase with the increase and change in cropping. Even more surprisingly, pumping rates actually decreased during the late 1970s to the early 1980s before finally stabilizing in the 1980s (fig. 4). Yet, there has been a steady decline in groundwater levels throughout the period under study. How does one explain these seeming contradictions?

Figure 3.Cropping history of Luancheng Country, 1949- 1999—summer crop sown areas		Figure 4. Irrigation history of Luancheng Country, 1949-1999—estimated pumping for irrigation

The cause: the policy–water use nexus

IWMI’s study used a water balance approach to try and find the answer. It is a simple accounting method used to quantify hydrologic changes. The soil water balance and the groundwater balance in Luancheng County were both studied (fig. 5).

The study concluded that the continued decline in groundwater levels is due to the longstanding agricultural policy of achieving food self-sufficiency by continually increasing the irrigated area, coupled with the use of groundwater to supplement precipitation. Even more interesting is what the study reveals about the connection between increasing irrigation efficiency and groundwater levels. In Luancheng County, irrigation efficiency has increased, causing more than a 50% decrease in groundwater pumping since the 1970s (fig. 4). However, groundwater levels continue to drop steadily. Because excess irrigation water seeps through the soil back to the aquifer underlying irrigated areas and replenishes the water supply, the only significant inflows and outflows to the system are through precipitation and crop evapotranspiration. As long as these two factors remain constant, increased irrigation efficiency will save no water. Instead, other options like reducing the length of the growing season and reducing the extent of irrigated land need to be considered to halt the decline of groundwater levels.

All water balance equations have the form:
Inflows – Outflows = S (1)

A soil water balance has the form:
P + I –ET – R = S = 0 (2)

And a groundwater balance has the form:
R – I = S (3)
where P is precipitation; I is irrigation water pumped from the aquifer and applied to crops; ET is crop evapotranspiration; R is drainage from the soil profile which then recharges the aquifer; ?S is the change in groundwater storage, as evidenced by water table declines.

In Luancheng County the average precipitation (P) for the study period was 460 mm/yr; the average evapotranspiration (ET) from the crops was 660 mm/yr. Substituting these values into the equations above we have:

P + I –ET – R = S = 0 (2)
460 + I – 660 – R = 0
R = I – 200
R – I = S (3)
I – 200 – I = S
S = -200
From the soil water balance (2) it is seen that drainage from the soil profile is 200 mm/yr less than the quantity of water applied as irrigation. This will remain so, as long
as rainfall and evapotranspiration remain constant.

Examination of the groundwater balance (3) shows that irrespective of the amount of water pumped from the aquifer for irrigation, the groundwater storage will decrease by 200 mm/yr and this equates to an annual drop in the water table of 1 m.

Figure 5. Generalized soil-water and groundwater balances of Luancheng Country Note: P is precipitation, I is irrigation water pumped from the aquifer and applied to crops; ET is crop evapotranspiration; R is drainage from the soil profile which recharges the aquifier; ?S is change in groundwater storage, as evidenced by water-table declines.		Figure General relationship between precipitation and evapotranspiration for cropland in Luancheng Country, 1947-2000		Figure 7.Hydronomic Zones in a river basin

Thus, simply changing the amount of water applied for irrigation will not affect the rate of groundwater depletion. The only other variables are rainfall and evapotranspiration. Clearly then, if there is to be any reduction in groundwater depletion and any real water savings, there must be a decline in evapotranspiration. This conclusion is further borne out by the relationship between rainfall, evapotranspiration and resulting depletion in groundwater over the study period (fig. 6).

In the early years before irrigation development, precipitation exceeded evapotranspiration and the excess water recharged the aquifer, sometimes even causing it to overflow. As irrigated areas grew and the number of crops harvested each year rose, evapotranspiration increased until it exceeded rainfall (fig. 6). It was at this point that groundwater mining began and since that time the amount of groundwater mined has been the difference between rainfall and evapotranspiration, irrespective of the amounts pumped out of the aquifer. As long as this difference remains virtually constant the rate of groundwater depletion too will remain constant.

Taking into consideration the entire hydrologic system, including both the soil profile and the underlying aquifer, has uncovered a simple but nevertheless vital factor that has been overlooked by water policy experts and resource managers over the years—that as long as crop evapotranspiration remains constant or increases there can be no reduction in the rates of groundwater depletion.

The answer lies therefore in methods that will either maintain or reduce the rates of evapotranspiration. The holistic study of the hydrologic system points us in the right direction in the search for these solutions.

A concept that is useful in studying hydrologic systems is that of hydronomic zoning. A hydrologic system such as a river basin is divided into hydronomic (Hydro water + nomus management) zones which are defined primarily according to the destination of the drainage outflow from water uses. Thus there are zones where water can be reused and those where it cannot, because of location and quality Expanding this further, each hydrological system can be classified into all or some of the following zones: water source, natural recapture, regulated recapture, stagnation, environmentally sensitive and final use zones (fig. 7).

The classification of the system into the different hydronomic zones helps identify the best methods of saving water since each zone has its own best set of water saving measures. In identifying these sets of measures, factors that must be accounted for are the extent to which the system has excess water available for depletion, the level of groundwater dependence, and the extent of pollution and salinity loading.

Description of zones

Water source – area where excess rainfall provides runoff or groundwater recharge for use downstream. The area where most of the runoff or water supply originates.

Natural recapture – area of the basin where surface and subsurface drainage water flows are naturally captured by river systems or channel networks. The water that is diverted but not depleted by evaporation in a use cycle will be naturally recaptured and available for reuse.

Regulated recapture – area where reuse of surface water runoff or deep percolation water can be regulated. Return flows are captured by a drainage network separate from distribution network and water does not naturally return to the system.

Stagnation – isolated area where drainage is insufficient for removal of leached salts and excess water. Usually consists of rising water tables and waterlogged and/or salinized areas.

Environmentally sensitive – area where there is a requirement for water for ecological or other environmentally sensitive purposes. Wetlands are a classic example.

Final use – area with no further opportunity for reuse of water, typically situated at the terminal end of the basin.

Conditions within zones: whether or not there is salinity or pollution loading or the opportunity of groundwater storage

A selection of possible answers

It has been proven that groundwater declines will slow only when water depletion decreases and will reverse only when net inflows exceed net outflows. Either there must be an increase of inflows or a decrease of outflows. In the Luancheng County what this essentially means is that precipitation must exceed evapotranspiration, i.e. measures must be taken to decrease evapotranspiration to a level less than annual precipitation.

The most popular and the most politically acceptable way of attempting to achieve this is to increase irrigation efficiency. However, IWMI’s study has clearly shown that this will not always be effective. Examining a hydrologic system as a system of hydronomic zones has shown that efficiency technologies will not be effective in natural and regulated recapture zones with groundwater storage and low salt build up. If there is significant salt build up or pollution in a regulated recapture zone, efficiency technologies will be useful in controlling pollution. These methods will also be useful where there is no significant recharge of the aquifer or where the recharge is heavily polluted or to decrease energy use. In a natural recapture zone such as Luancheng County irrigation efficiency will not be effective in stemming groundwater decline. Thus, a variety of other options have been suggested and considered.

Figure 8. Estimated groundwater declines that would have resulted from five different summer and winter crop combinations under typical irrigation practices, given historical climate conditions in Luancheng Country, 1962-2000

A measure that is often suggested for water conservation is water price increases to increase irrigation efficiency. In the case of the Luancheng County this might not be appropriate since in this case, reducing pumping but irrigating the same area will not stop groundwater decline. Rather, what is required is a change in land use; whether this will ensue from higher prices is debatable.

Aside from irrigation efficiency there is a variety of water saving technologies which are put forward as one of the solutions. Some of these technologies may exacerbate the problem if used inappropriately. For example, while sprinkler irrigation will save energy and allow for more precise application of water and fertilizers leading to higher yields, it will not always be effective in reducing groundwater decline and in some situations might even aggravate the problem if farmers decide to irrigate more crops with the water they save. Technologies that reduce evaporation such as the use of mulching and the establishment of greenhouses would be ideal for Luancheng County.

Changing the cropping pattern is one possibility which needs to be carefully looked at. Adopting less waterintensive cropping patterns than the currently predominant winter wheat/summer maize combination is one suggestion. The amount of water saved will depend on the length of the growing season, the root depth and the leaf area. Studies have shown, however, that any cropping routine which includes a winter wheat cycle will not show any significant reduction in groundwater depletion (fig. 8). It would appear then that the reintroduction of a winter fallow season is the only way of seeing any significant water savings through crop changes. This, unfortunately, is not an option which, by and large, is likely to be socially and economically palatable.

Another option is the transformation of land use from rural to urban. While specific data is not available for the Luancheng County, it is commonly accepted that urban land use depletes much less water than crop evapotranspiration. An urban setting would call for a different range of water conservation measures. In the city of Shijiazhuang, overpumping of groundwater has resulted in the deformation of the water table into a funnel shape. This has affected elevations of water levels at different points and has caused directional changes to the natural flow of groundwater. Thus water that would naturally have flowed to the aquifers of Luancheng County is flowing instead to the aquifers of Shijiazhuang city. It is imperative that the net amount of water pumped for the city is reduced if this unsustainable situation is to be reversed.

In an urban setting, precipitation tends to leave the system as runoff, rather than recharging the underlying aquifer, since many of the land surfaces are impermeable. Here, unlike in the study area, efficiency technologies would have a significant effect. A more expensive option is that wastewater is treated and then used to recharge the aquifer. Studies in California have shown that both these measures, though expensive, show better results in terms of water yield-to-cost ratios than agricultural water conservation, land fallowing and surface storage construction.

With respect to improving urban water use efficiency industrial facilities provide greater potential savings than do households. Water use per industrial product in China is 3 to 10 times greater than in other industrialized countries. Discouraging water-intensive industries is a measure that has been adopted in some Chinese cities. Likewise there are many different measures that can be considered singly or together in the urban context to provide optimal water use efficiency.

Making the right choice…

Figure 9. Examples of land-uses which, combined, deplete approximately 460 mm/year of water—under the assumption that all wheat and maize is either mulched or replaced with vegetable crops, thereby reducing evapotranspiration by 100 mm/year

None of the measures described earlier will be sufficient on their own to solve the problem of groundwater depletion. Thus, an appropriate mix of measures must be identified to achieve optimal water savings and reduced levels of groundwater depletion.

Using the kind of thinking underlying the concept of hydronomic zoning, together with a water balance approach, the study in Luancheng County set out to identify the right mixture of solutions. It formulated water saving choices which could be adopted. The sets of options are made up of a combination of changing cropping patterns, leaving certain areas of land to lie fallow, and change of land use to urban uses. Each set of options is calculated to deplete only 460 mm/yr— bringing the rainfall and evapotranspiration into equilibrium (fig. 9).

This analysis leads to the conclusion that withdrawing some land from irrigation is an inevitable part of the solution to achieving sustainable water use in the North China Plain. This change in land use will be flying in the face of the longstanding policy of food self sufficiency and use of groundwater to meet this goal. Thus, incentives which are socially, politically and economically acceptable will need to be offered to bring about this change.

In the final analysis, it is clear that simplistic ‘one size fits all’ solutions will not always be effective in saving water. A holistic approach including techniques such as a water balance approach and hydronomic zoning is necessary to identify the most effective methods of halting and reversing rates of groundwater decline.