Water Management in Dry land And Irrigation Scheduling in Tobacco is given in this doc

1. 1
Introduction
Dryland ecosystems are characterised by frequent droughts, inherent low levels of biological
productivity and low soil fertility (Thomas, 2007, MEA, 2005). They are also among the world’s
most variable and unpredictable environments where rainfall is low and erratic and there is high
inter-annual climate variability (Hesse, 2011). Combined with social, economic and political
factors these environmental challenges make dryland regions complex development spaces, one
outcome of which has been their political and economic marginalisation. The result has been
pervasive poverty and underdevelopment in dryland areas; yet with marginalisation there is also
an increasing realisation that dryland areas have significant development potential. Securing water
resources to overcome variability in its access, as well as to smooth out the climate extremes is
central to unlocking the development potential of dryland areas (Nkonya, E., et al, 2011). Given
that the other key resources of drylands include generally higher temperatures and abundant solar
energy, which is increasingly seen as a catalyst for socio-economic development. A strategic
development of transport infrastructure and improvements in access to markets coupled with
sustainable development and management of water resources could lead to the transformation of
dryland areas, and their related contributions to socio-economic development. However, with this
push to develop and transform dryland areas also comes contestation over access and control of
resources, especially water and land.
Approaches to water development in dryland areas range from; development of groundwater
resources through boreholes for domestic and productive uses, capturing more surface water in the
soil, soil and water conservation, to water harvesting (Hutchinson and Herrman, 2007). Many past,
and to an increasing extent current, efforts in dryland sub-Saharan Africa have focused on the
construction of dams and large irrigation schemes, as well as borehole construction, to improve
water supply mainly for agricultural production. Past efforts to increase crop production in dryland
regions in Africa, from the 1930s to 1970s, centred on the establishment of large-scale irrigation
schemes such as the Gezira Scheme in Sudan, Chokwe Irrigation Scheme in Mozambique, Office
du Niger in Mali, SAED in Senegal and AMVS in Burkina Faso. In Asia, a key aspect of the Green
Revolution in the 1960s and 1970s also focused on extensive irrigation development in dryland
regions. These largely state-led water development approaches were fraught not just with a failure
to operate effectively, but also to deliver their anticipated benefits – much of this the result of
poorly thought-through planning.
It has been the prioritisation of technological solutions over governance approaches, as well as of
centrally state-driven developments, combined with poor overall management, that have so often
led to development of unsustainable irrigation and borehole infrastructure. As awareness has
increased of the negative environmental impacts of such developments, however, and particularly
in the context of rapidly expanding human and livestock population, planners and decision-makers
have begun a ‘re-reading’ of policy and practice. This revisionism is important, especially in
contemporary East Africa, where there is renewed interest in water development in drylands,
including by external foreign investors keen to develop irrigated agriculture that serve international
food, biofuel and cash-crop markets. Governments in the region view new growth opportunities in
irrigated agriculture (both small-scale and large-scale) – for instance sugarcane production – as
part of wider agro-industrial development. A significant part of dryland areas in East Africa are in

2. 2
lowlands, where alluvial riverine lands are now being sought out for development. To exacerbate
matters further, increasing upstream hydropower developments are also adversely affecting and
reducing downstream flood pulses, which Good Practices in Water Development for Drylands 5
hitherto have been key to the survival of many pastoral societies. These and other emerging (and
converging) development processes place ensuring effective and equitable water development for
all communities in drylands regions at the heart of contemporary challenges – and development
policy – in East Africa.
Inappropriate approaches to water development in dryland areas of East Africa have adversely
affected environments and livelihoods. Pressure to meet national domestic water service targets
has led to construction of many water supply points (mainly boreholes), an approach that has often
failed to take account of pastoralist patterns of mobility. Furthermore, the focus on borehole
construction has not been supported by a systematic data collection framework, the
implementation of which, would have contributed to the effective monitoring of the groundwater
resources on which such boreholes rely. Basic aspects of borehole water supply points, such water
level, strike depth, discharge rates, water quality and functionality (including breakdown periods)
have often not been collected. This is still largely true despite the fact that the aforementioned
information is required by the ministries of water in the region as part of a water resources and
environmental impact assessments.
In some cases, water points were left in disuse when pastoralists moved in search of pasture, in
other cases they encouraged pastoralists to settle in their vicinity effectively constraining their
mobility and triggering land degradation. In worst cases, such water developments have
precipitated conflict among groups through engendering competition over resources. Capturing
good practices and principles encourages the formulation of appropriate water development
approaches that not only enhance water access in pastoral areas but also support the mobility of
pastoralists across rangelands and ensure sustainable use of resources (REGLAP Water Learning
Group, 2013). Through specific strengthening of pastoral livelihoods, this approach supports wider
productivity and sustainability of dryland agro-ecological systems.
In the context of rapid change in dryland areas, good practices in water development will ensure
the sustainable development and use of water across sectors as well as reducing such developments
wider environmental and social impacts. The focus on agricultural development – especially
irrigation development in the Ethiopia, Kenya and Uganda – and the policy shift towards
sedentarisation of pastoralists, as well as nascent development of hydrocarbons and other mining
sectors and urban expansion into dryland areas, is precipitating structural changes in the nature
and type of demand for water. These developments will inevitably transform existing livelihoods
of people living in dryland areas and establish a new resource-population relationship, and not
necessarily of mutual benefit. By adhering to good practice principles of water development,
planners can not only ensure more sustainable utilization of water across sectors, but also enable
people living in dryland areas to find alternative and viable livelihoods through stronger
contributions to economic growth and social development in drylands regions.
Enhancing the livelihood security of pastoralists, agro-pastoralists and other water users through
improved approaches to water development can strengthen the contribution of drylands to national
economies, and reduce their drain on resources by enhancing resilience and reducing the need for

3. 3
food and other cash interventions during emergencies brought on by climate extremes, whether
floods or droughts. Improving water development and management, particularly through
ecosystem-based approaches, enhances the productivity and sustainability of soil, water and
vegetation resources. This improves the resilience of both human communities and ecosystems to
climate change, for example Good Practices in Water Development for Drylands 6 through the
contributions of ecosystems to food security, thereby creating a ‘virtuous cycle’ within which
stronger livelihoods reduce the likelihood of the use of adverse coping strategies that damage the
environment (e.g. grazing mismanagement, deforestation for wood fuel or charcoal). They also
lead to improved soil and water conservation, thereby reducing the need for further interventions
such as use of fertilisers, construction of water infrastructure and ultimately emergency drought
and flood responses.
Through analysing good practices and principles on water development in a dryland context from
other parts of the world, this study provides improved understanding of sustainable approaches to
water development for multiple uses in dryland environments. It also helps to improve the wider
environment of livelihoods diversification and non-pastoral livelihoods options. Insights gained
from other areas, and that can be adapted to the East African context also help to demystify these
sometimes remote regions, reducing misunderstanding of their productive potential and capacity
for resilience, and supporting better integration within wider national and regional development
contexts, including through the regional economic integration processes of the East African
Community.
The water requirement pattern for tobacco (Yun 85) was identified based on analysis of data
obtained from pot experiments in a canopy at the Xiuwen Irrigation Test Central Station in
Guizhou Province, China. The results showed that the tobacco water requirement and the tobacco
water requirement intensity throughout the growth period in pot experiments were significantly
lower than those in field production. In pot experiments, the tobacco water requirement throughout
the growth period ranged from 159.00 to 278.90 mm, with a reduction in the range of 241e441
mm, as compared with that in field production. Also, the average water requirement intensity at
the vigorous growing stage was 1.97 mm/d, and the water requirement and water requirement
module were 33.80e72.60 mm and 16.39%e33.09%, respectively, at the group stage, almost equal
to their values at the vigorous growing stage. The patterns of the tobacco water requirement and
water requirement module in pot experiments were different from those in field production. In pot
experiments, the tobacco water requirement and water requirement module ranked the highest at
the mature stage, followed by those at the group/vigorous growing and rejuvenation stages, while
the water requirement intensity ranked the highest at the vigorous growing stage, followed by those
at the mature, group, and rejuvenation stages. The pattern of the
water requirement intensity in pot experiments was consistent with that in field production. In
addition, the response of the tobacco water requirement to water deficit was also analyzed. Serious
water deficit at the vigorous growing stage and continuous water stress at the group, vigorous
growing, and mature stages can greatly influence the tobacco water requirement. Water deficit led
to reductions in the water requirement and water requirement intensity at each growth stage. The
vigorous growing stage exhibited the highest sensitivity to water deficit. The lower limit of
moderate soil water stress at the vigorous growing stage was 65% of the field capacity. Results of
this study can help to establish a reasonable irrigation schedule for tobacco production in Guizhou
Province, China.

4. 4
Objectives of the Study
Broadly, the overall objectives of the study are to provide evidence of effective approaches to
water development in dryland areas; to analyse what they achieved and how – and within which
policy and practice environments; to assess whether they were successful or not and why; and to
make suggestions for their transferability to and within the Horn of Africa policy context, with a
focus on practical suggestions that can help to overcome challenges and build opportunities.
The main objectives of this study are fourfold, and they are;
1. To provide evidence of effective approaches to water development in dryland areas.
2. To analyse the specific achievements of effective approaches to water development in dryland
areas, and how these were achieved in practice.
3. To highlight the key factors that underpin successful (or failed) water development projects.
4. To make suggestions for transferability of good practice principles to the Horn of Africa context.
The specific objectives are;
1. To identify case study examples from global dryland areas demonstrating the use of good
practices in water development.
2. To examine what made these case studies successful or not, what was the enabling policy and
practice context, and what were the impacts of such approaches, both positive and negative.
3. To analyse the policy and practice contexts for water development in the Horn of Africa and
consider specific opportunities and challenges to adopting such good practice approaches.
4. To provide practical suggestions for replicating good practices, in terms of enabling different
ways of working, overcoming implementation barriers, and policy opportunities and constraints.
In view of the objectives of this study, it can be stated that through analysing good practices and
principles on water development from other regions this report is aimed at providing improved
understanding of sustainable approaches to water development in dryland environments for
different and multiple uses. Such improved understanding of good practice principles in water
development and management will help policymakers and practitioners in the Horn of Africa to
design, implement and manage better approaches to water development in dryland areas. This will
not only help in the sustainable management of water resources in dryland area, but also improve
the wider environment of livelihoods diversification and non-pastoral livelihoods options. Insights
from other regions that can be adapted to the East African context also help to demystify these
sometimes remote regions, reducing misunderstanding of their productive potential and capacity
for resilience, and supporting better integration within wider national and regional development
contexts, including through the regional economic integration processes of the East African
Community.

5. 5
Summary
As little as 17% of precipitation that falls in dryland systems actually gets used by the crop. So the
question is, "what happens to the rest of the precipitation?" Precipitation is 'lost' for crop use
because it is intercepted by the crop or other vegetation, runs off from the soil surface to another
location, evaporates from soil or other surfaces without entering the crop root zone, percolates
below the crop root zone, or is transpired by weeds or other non-crop plants. Water conservation
practices are designed to eliminate or minimize these 'losses' to conserve precipitation in the crop
root zone for crop use. However, it is important to note that although these are 'losses' to the
cropping system, the lost water is not lost from the system as a whole and the water may be
beneficially used by the crop or ecosystem elsewhere. For example, water runoff may be captured
somewhere else in the field for crop use or contribute to a watershed's yield. Likewise, deep
percolation can recharge groundwater for other uses as well.
The Regional Learning and Advocacy Project (REGLAP) recognise that there is need for
sustainable water development and management in the dryland regions of Ethiopia, Kenya, and
Uganda. This recognition stems from three main concerns:
1. The uncoordinated nature and inappropriate approaches to water development by humanitarian
organisations and water engineers, which have potential damaging impacts on local ecological
systems and livelihood activities in the three countries (REGLAP Water Learning Group, 2013).
In the past, construction of boreholes in pastoral areas of Uganda, Kenya and Ethiopia has resulted
in constraints on the mobility of pastoralists and – to a certain extent – the sedentarisation of some
pastoralists groups, adversely affecting their livelihoods and the productivity of pastoralist systems
more generally.
2. An observed increase in the frequency of extreme weather events, including rising episodes of
droughts and floods, has also negatively affected the wellbeing of local populations, their
livelihoods and the surrounding environment. The impact of the 2010/2011 drought is a case in
point, with serious negative repercussions for populations in Northern Kenya and Southern
Ethiopia underscoring the need for future and more sustainable water development in these dryland
areas.
3. More recently, the increasing focus on dryland areas as centres for investment in crop
agricultural development, mining, tourism, and urban expansion. Consequently, as more
investments are targeted in drylands, there is a need for water development to meet the water
requirements of diverse and often competing sectors, while at the same time maintaining healthy
ecosystems and sustainable local livelihoods.
Within this context, the Water for Disaster Risk Reduction Learning Group of REGLAP, led by
IUCN, was created. The group’s aim is to collate and disseminate practical examples of good
integrated water development in drylands in order to influence and provide practical guidelines for
policy makers and practitioners. The REGLAP Water Learning Group has produced an initial set
of guidelines entitled ‘Good Practice Principles – Water Development in Dryland Regions’ based

6. 6
on a collation of stakeholder views of ‘good practices’ during both ‘normal’ periods and in drought
emergencies. The guidelines provide a first step in a broader process of dialogue, including the
standardisation of water development approaches and the identification of a ‘lobbying agenda’ for
sustainable water development and service provision within dryland areas.
This report is a follow-up to the REGLAP Water Learning Group’s Guidelines and aims to
demonstrate the ways in which these principles work in practice with a view to informing further
practice and policy on water development and management in dryland areas in Ethiopia, Kenya
and Uganda.
Based on the findings of this report, and the existing guidelines referred to above, a revised set has
also been developed with a focus on practical development of water resources for dryland
agriculture and pastoralism – and mixed systems.
Key findings of this report which feed into the guidelines are as follows:
Critical contexts: dryland areas are complex, and this complexity requires that critical attention is
paid to specific system attributes, the relationships between systems within a landscape context
(such as, the relationship between drylands and higher-rainfall areas within a catchment/or even
sub-catchment area) and that developers take into account environmental, social and historical
contexts. Complexity is at the heart of challenges facing water development in drylands and all
too often agencies and governments have taken an overly simplified view of water resources
development, prioritising the delivery of the resource over the impact this will have on the complex
interactions between land, environment and the frequently overlapping livelihoods systems. Such
a flawed approach to water development, coupled with the high levels of poverty, and
marginalisation in dryland areas exacerbates water scarcity.
Presence of key institutional, legal and governance frameworks and the ways in which they
function to provide equitable access to water to various users:. Consequently, such institutions
provide a participatory framework for local level water governance that ensures the participation
of different water users in decision-making processes on water. Effective and genuine stakeholder
participation in water development and management is critical to successful water development.
The success of decentralised and participatory water governance frameworks have been enhanced
when their establishment has been backed by legal reforms that empower such institutions to
effectively carry out water development and management functions. Similarly, at sub-national
level, local-level water management institutions and that empower water users to participate in
local decision-making and financing of water management, have been more successful. Several
aspects are key to these water governance frameworks, such as:
Policy reform that effectively establishes decentralised institutions of water management and
associated legislative reforms that empower water users in decision-making processes on water;
Genuine participation of various water users in water development and management, clarity of
stakeholder roles and responsibilities; support for local ownership of local level institutions of
water management; and,

7. 7
Fruitful engagement between formal and informal institutions in water management; and local
financing of water management processes in the long term.
The vital role of women as water managers and users needs to be recognised and placed at the
heart of frameworks for water development and management. More often than not, women have
been marginalised and excluded from decision-making environments and have not been able to
contribute to effective development of the resource.
• Wider economic and social linkages: Economic and social linkages to wider national (and
regional) economies shape political-economic drivers of change in dryland areas (for instance
markets for water, charcoal and wood fuel). These linkages are constantly changing and critically
influence how and where water development takes place. These wider linkages challenge
received wisdom on integrated water resources management and suggest the need for a ‘problem-
shed1’ approach to water development in drylands (including, for example, how external market
demand for water, livestock and biomass fuels – wood and charcoal -- interrelate).
• Emerging from our case study material and analysis is a framework for water development in
dryland areas that focuses on three elements:
o Current Water Supply and Availability: how water availability responds to a range of
environmental factors (including rainfall, runoff, recharge and surface and groundwater flows);
o Current Water Demand and Uses: the structure of demand surrounding the resource, including
the stratified nature of demand across livelihoods systems and by different sectors; and
o Future Possible Demand and Uses: the kind of scenario planning that is necessary for longer-
term sustainability, including political-economic analysis and growth projections.
• Two cross cutting elements relate to the nature of systems of resource use, namely capacity and
sustainability. The latter refers to social, technical and environmental sustainability. There is a
strong emphasis on using resource governance to achieve a balance between these elements,
particularly under the influence of external pressures including land grabbing and changes in the
market for livestock products.
Identified examples of good practices in water development for dryland areas include ensuring
that water development projects serve the flexibility and mobility of users of the resource in
dryland areas. These are frequently – though not always – pastoralists and pastoral herds and this
refers to ideas of “opportunistic range management” and the success of these systems.
Addressing knowledge gaps between local perceptions and those within government, donors and
NGOs on water-related, ecological dynamics and social issues brings indigenous knowledge closer
to decision-making and reduces the likelihood of failed interventions caused by inadequate or poor
use of knowledge and information. A specific area in this respect is how to increase drought
preparedness and management, including managing the most severe or ‘decadal’ droughts that
affect parts of East and the Horn of Africa. Underpinning a suite of resource development options
is basic capacity building, civic education and information, advocacy, and skills for managing
water development.

8. 8
Discussion
1. Water conservation
Water conservation in the arid and semi arid regions is an important issue that influences both the
environment and crop production. Runoff which is induced by rainfall can cause soil erosion which
poses a dominant threat against long-term sustainability of farming (Derpsch et al., 1986). A
further problem usually associated with runoff is the loss of soil particles that may pollute water
bodies. Pollutants commonly found in runoff include soil particles, phosphorous, nitrogen,
pesticides, etc. (Motavalli et al., 2003a)
During runoff, soil particles in the form of displaced sediments are carried along with the flowing
water. The runoff mostly settles around the edge of a dam and the sediments it contains will
subsequently be deposited underneath the reservoir. This continuous and gradual silting of the dam
over time will consequently affect its capacity to store water.
The decrease in the capacity of reservoir depends on the concentration of soil particles in the river
that supplies the dam. In spite of decades of concerted research efforts, sedimentation is still
considered the most serious problem threatening the dam industry. The deposition of soil particles
in the dam may decrease the efficiency of the dams’ turbines.
2. Soil and water conservation practices in dryland farming
Dryland farming is the profitable production of useful crops without irrigation on lands that receive
annual rainfall of less than 500 mm per year. In the arid and semiarid regions, the conservation of
precipitation water for crop production is very vital. In dryland crop production areas, a major
challenge is to conserve precipitation water appropriately for use during crop growth (Baumhardt
and Jones, 2002). It is imperative that farming practices should conserve and utilize the available
rainfall efficiently. To optimize water storage under any precipitation condition, the soil should
have enough infiltrability, permeability and capacity to store water. Water is the main constraint
in dryland farming in the West of Iran. Precipitations tend to accrue during winter, while crops’
growth season in spring is accompanied by high temperatures. These conditions are the constraints
limiting crop production in dryland agriculture in Iran (Hemmat and Eskandari, 2004b).
3. Tillage
The objective of tillage operations is to improve soil conditions including porosity, temperature,
and soil water storage capacity for increased crop production (Alvarez and Steinbach, 2009).
Tillage systems that practise conservation farming during the winter are known as important
methods in controlling soil erosion and runoff (Alvarez and Steinbach, 2009; Derpsch et al., 1986).
Tillage practices play an important role in dry farming agriculture; however, the appropriate
implements, their time and method of use have to be specific for different agro-climatic zones.

9. 9
3.1 Conservation tillage
Conservation tillage research studies have focused on the effects of tillage practices on soil and
moisture conservation for increased crop production, water conservation and soil erosion control.
Several studies have attempted to develop appropriate and sustainable tillage and residue
management methods that would maintain favorable soil conditions for crop growth. After harvest,
stubble mulch is accumulated on the soil surface. Such materials do not only prevent direct impact
of raindrops on the soil, but also impede the flow of water down the slope, thereby decrease the
water flow on the soil surface and increase the amount of infiltration water (Hemmat et al., 2007).
Conservation tillage systems have the potential to improve soil quality and reduce soil loss by
providing protective crop residue on the soil surface and improving water conservation by
decreasing evaporation losses (Su et al., 2007). Tillage creates a rough cloddy surface that
lengthens the time necessary for the rain to break down the clods and seal the surface.
Reduced tillage practices have been used in the production of many crops to increase soil water
conservation (Locke and Bryson, 1997; Peterson et al., 1998). Reduced tillage practices protect
soils from erosion and runoff by maintaining more crop residue on the soil surface. The magnitude
and trends of change in soil physical properties depends on antecedent conditions, wheel tracks,
soil texture and climate (Hobbs et al., 2008). However, contradictory results have been reported in
literature about these effects. Mahboubi et al. (1993) showed the beneficial effects of long-term
conservation tillage systems including chisel plowing and no-tillage compared to conventional
tillage in ameliorating soil physical properties.
Compacted soils of arid regions have low organic matter contents and are proned to crusting which
may decrease infiltration, seedling emergence and plant growth (Unger and Jones, 1998). For soils
that are hard setting or have a root-restricting layer, some form of mechanical loosening through
deep tillage is necessary to conserve the soil and water in order to facilitate crop growth (Nitant
and Singh, 1995; Vittal et al., 1983). On the other hand in some soils, water conservation and water
and wind erosion contros are major goals of conservation tillage systems. Any tillage method that
keeps residue on the surface may protect the soil against dispersion by rain drop impact and the
pounded or flowing water will decrease crusting (Hoogmoed and Stroosnijder, 1984; Pikul Jr and
Zuzel, 1994)
3.2 Comparing various tillage systems
Studies have revealed that tillage operations do modify soil properties including soil structure
(Roger-Estrade et al., 2004; Saggar et al., 2001), bulk density and porosity (GLSB and KULIG,
2008; Lampurlanés, 2003; Unger and Jones, 1998), water retention and distribution (Hemmat et
al., 2007), root growth and yield (Box Jr and Langdale, 1984; Busscher and Bauer, 2003; Shirani
et al., 2002; Su et al., 2007). Conventional tillage methods used by farmers result in physical
degradation of soil and increased soil erosion and runoff (Unger and Fulton, 1990). Excessive
tillage results in deterioration in the soil environment and also increases the cost of production. On
the other hand, the no- tillage system can affect the growth and establishment of plants through

10. 10
increased weed competition and poor soil physical conditions. Reduced tillage has been found to
be feasible in improving soil properties (Locke and Bryson, 1997; Peterson et al., 1998). Each
tillage system modifies soil properties differently. Moldboard plow buries plant residues and
stubble, but chisel plow enables retention of plant residues on soil surface.
3.3 Organic amendments and tillage
Previous studies have reported that application of sewage sludge, compost, farmyard manure and
other kinds of organic amendments resulted in a significant increase in aggregate stability, water
content, hydraulic conductivity and infiltration and a decrease in bulk density (Arshad and Gill,
1997; Bahremand et al., 1999; Motavalli et al., 2003b; Shirani et al., 2002). Some literature
reported that application of manure to the soil decreased soil compactibility (Mosaddeghi et al.,
2003). They also showed that mixing manure with the soil does not only decrease compactibility
but also decrease subsoil compaction.
4. Mulching and water conservation
Stubble mulching aims at disrupting the soil drying process by protecting the soil surface atall
times either with a growing crop or with crop residues left on the surface during fallow. The first
benefit of the stubble mulch is that wind speed is reduced at the surface by up to 99% and,
therefore, losses due to evaporation are significantly reduced (GLSB and KULIG, 2008). In
addition, crop residues can improve water infiltration (Hemmat and Taki, 2001) and decrease water
runoff losses (Morin et al., 1984). Layered mulch could keep soil moist, change soil moisture
regime and help to keep the soil moist(Sadegh-Zadeh et al., 2009). The decrease in evaporation by
layered mulch was due to the ability of the mulch to decrease soil temperature during the hot-dry
season. Other studies on mulching and soil moisture showed that tephra mulch could keep more
soil moisture than the un-mulched soil and tephra mulch were able to change aridic soil moisture
regime into a udic one.
5. Rainwater Harvesting
Extreme variability of rainfall, with high intensity, few rainfall events, and poor spatial and
temporal distribution is one of the key limiting factors for crop and livestock production. When
rainfall occurs in dryland areas, much is lost to run-off and evapo-transpiration. Therefore, local
harvesting or capturing a proportion of rainwater in wet periods, utilising the same for productive
purposes (e.g., supplemental/protective irrigation, domestic supply and livestock use) during dry
spells, offers a promising solution to challenges of uncertainty. However, in cases where rainwater
harvesting captures surface water flows, this might mean that water captured no longer replenishes
groundwater resources and thus might have knock-on adverse effects.
It is important to note that water harvesting can occur at both the micro- and macro-catchment
level, and may involve the diversion and spreading of run-off onto fields or the collection of
rainfall and run-off in inexpensive water storage systems. Rainwater harvesting at both micro-and

11. 11
macro-catchment level has been successfully used to provide water for domestic use, livestock and
crop production in many dryland regions.
6. Conjunctive Use of Surface and Underground Water
Conjunctive use of surface and groundwater sources is one of the most effective ways to buffer
water supply availability against high flow variability and drought propensity in both rural and
urban areas in many dryland regions. Conjunctive use of groundwater and surface water sources,
in some form or other and with varying degrees of effectiveness, is capable of achieving:
• much greater water-supply security – by taking advantage of natural groundwater storage in
aquifers larger net water-supply yield – than would generally be possible using only one source
alone
• better timing of irrigation-water delivery – since groundwater can be rapidly deployed to
compensate for any shortfall in canal-water availability at critical times in the crop-growth cycle
• Reduced environmental impact – by counteracting land water logging and salinisation, and
excessive river flow depletion or aquifer overexploitation.
7. Key Governance Factors Underpinning Successful Water
Development
The analysis of the available case study evidence, drawn primarily from Africa, Asia and Latin
America, indicates that many governance factors underpin conditions for successful water
development projects in drylands. These include:
1. Political will and commitment to water development in drylands by government and local
political actors. Evidence from Brazil and India clearly demonstrates that political commitment by
regional government and other state (and sub-state) agencies were instrumental in successful
dryland water developments. In Gansu, China, the government provided 50% subsidies to support
the implementation of the rainwater harvesting project; in Ceara, North East Brazil, the regional
government collaborated with 700 NGOs, state universities, and other government agencies to
construct cisterns for rainwater harvesting that provided safe water supply to five million people.
From the analysis undertaken for this report, it is apparent that the the stronger the political support
the more successful a particular programme activity will be.
2. Political stability and robust local-level systems of governance. Successful water development
projects in drylands took place when the respective countries and/or regions were experiencing
periods of political stability. For instance, the One Million Cisterns Project in northeast Brazil was
implemented after Brazil’s transition to democracy in 1988.
3. Availability of national and local development plans. Evidence from the provision of water
supply services as part of emergency relief during drought periods in Botswana and Zimbabwe

12. 12
show that the existence of district water development plans and a government-led institutional
frameworks for rapid implementation were central to the success of drylands water development
projects during emergency periods. The district water development plans provided a coherent
framework for water development, which was adhered to during drought periods. Further, the
active role of government and local authorities in leading water development plans, meant that
even in crisis periods, they maintained the oversight role when other actors, such as NGOs, were
involved in providing water supply services to communities affected by a drought or flood.
4. A good degree of coherence in policies and processes for implementation. The levels of policy
coherence will determine how clearly roles and responsibilities in water development in dryland
areas are defined, which has implications for successful delivery of projects and programmes.
Integrated approaches to natural resources management (for instance, including various
combinations of water, land, forestry and livestock) have been central to successful drylands water
development projects in India, Nepal and Burkina Faso. In India and Nepal, integrated
management of forestry and water resources underpinned the success of watershed and rainwater
harvesting projects. Further, policy coherence and integration also reflected other development
needs such as market integration and infrastructure development.
5. Decentralised frameworks of local administration and governance of water and natural
resources. The establishment of viable, local level institutions of water management in dryland
areas were central to the success of all projects in the case studies reviewed. This was mainly
because they enabled people’s participation in planning, implementation, and maintenance of
project activities. This is illustrated by the Ceare study on rural water supply in Brazil and
watershed project in India.
6. Capacities for collective action. Successful water development projects in dryland areas
depended, in part, on the ability of a wide range of actors (i.e., from government agencies, non-
governmental organisations, civil society, donor agencies and private sector organisations) to work
together in planning and implementation. Where capacity for collective action was low, because
of either limited space, social difference, or conflict, it was unlikely that water development
projects would be implemented, let alone sustained.
The governance factors described above are not an exhaustive list, nor do they represent a linear
causal relationship between one factor’s presence and successful water development in dryland
areas. Rather, the presence of one or more of the above led to greater success.
The importance of an analysis of governance factors is that it calls attention to the relationship
between the wider governance environment and implications of successful water development
policies, programmes and projects in dryland areas. It also promotes and enables practitioners to
be aware of interactions between governance factors and the outcomes they seek tp achieve
through water developments. Given varying contexts, clearly outcomes might vary from one
country to another.

13. 13
8. Materials and methods
8.1 Site characteristics and soils
The experiment was conducted at three sites in one of the famous areas of dryland wheat
production in Bijar, Kurdestan province of Iran. The soils belong to the Aridisols order (Soil
Survey Staff, 2006). The soil of the experimental sites consist of different textural classes (sandy
loam, loam and clay loam). The mean annual precipitation of the region is 400 mm, most of which
is received from late autumn, winter and early spring. During winter, most of the precipitation
water is converted into snow. The soils of the region have low organic matter and nitrogen, with
medium amount of phosphorus and high potassium content. The soil had been cultivated since
long time ago. The climate of the area is characterized by a cold and snowy winter and a warm
and dry summer with high evapotranspiration potential (in excess of 1500 mm in an evaporimetric
tank).
8.2 Experimental site and design
8.2.1 Tillage treatments
Three tillage treatments were imposed during seed bed preparation. The plot layout was arranged
using a randomized complete block design with four replicates. Plowing operations were carried
out in April 2003 and disking was performed twice in September of 2003.
Tillage systems used were as follows:
Moldboard plow (MP) (200 mm depth) and twice offset disking (70 mm depth).Chisel plow (CP)
(300 mm depth) and twice offset disking (70 mm depth).Deep plow (DP) with subsoiler (450 mm
depth) and twice offset disking (70 mm depth).The experimental design for each soil type was a
spilt-split plot with three tillage systems as main plots, manure applications (no application,
application of 3 mm thickness of farmyard manure (FM) on soil surface after sowing and mix same
amount of FM with the soil surface (70 mm depth before sowing) as split plots, and planting (no
planting and planting) as split– split plots. Each plot size was 2 m × 20 m in four replications.
Fertilizer including urea, ammonium phosphate, and microelements (Zn, Mn, Fe and Cu) were
applied before sowing according to soil analysis results and recommendation rates. Wheat
(Triticum aestivum L.) seeds (cultivar Sardary) were sown (at a rate of 150 kg ha-1) and weeding
was done manually.
8.3 Runoff and soil loss
Runoff and soil loss were measured in each plot. The plot edges were made of solid materials
(wood plank). The edges of the plots were about 15 cm above the soil surface to prevent input
from splashes entering the plot from the surrounding areas and were sufficiently embedded into
the soil. Runoff and soil loss were measured by collecting the runoff water in 40-liter capacity
buckets (Khan and Ong, 1997), which were placed at the bottom of each plot. The collection

14. 14
buckets were connected to the runoff plots via PVC tubes, which collected both soil sediments and
runoff water from the each plot after every rainfall event. Sediment concentration was determined
through sampling collected runoff at the out let of each plot. Sediment content was determined by
means of drying and weighing (Inbar and Llerena, 2000). Sediment yield was assumed to be equal
to the rate of soil erosion. Runoff and sediment measurements were conducted from cultivation to
harvesting stages.
8.4 Measurement of soil properties
The measured soil properties were pH, CaCO3 content, soil water content at field capacity (FC)
and permanent wilting point (PWP), organic matter (OM) content, particle size distribution,
electrical conductivity of saturation extract (ECe), cation exchange capacity (CEC), and soil bulk
density. Soil bulk density was measured on undisturbed core samples (Blake and Hartge, 1986).
Particle size distribution was determined by the Bouyoucos hydrometer method (Bouyoucos,
1962). Water infiltration rates were determined in the soil surface of various treatments using a
double-ring infiltrometer (Bouwer, 1986). The CEC was determined according to method used for
alkaline soils (Bower et al., 1952). The pH and electrical conductivity were determined from
asaturated past extract (Rhoades, 1982). The amount of CaCO3 was determined by acid
neutralization ethod (Allison and Moodie, 1965) and the OM content was determined by the
potassium dichromate oxidation method (Nelson et al., 1982). The soil water content was
measured using gravimetric method. Water retention capacity was measured at FC (− 33 kPa) and
PWP (− 1500 kPa) (Gardner and Klute, 1986). Soil water content was measured at depths of 1 to
100 cm in every 5 cm intervals by the gravimetric method.
Wet aggregate stability was determined using the method of Kemper and Rosenau (Kemperand
Rosenau, 1986). Fifty grams of air-dried aggregates (3–5 mm diameter) from each soiltype was
wet sieved through a 2 mm sieve. The sieving time was 10 min at 50 oscillations per minute. The
percent of aggregate size bigger than 2 mm was calculated and used as an aggregate stability index
among treatments. Soil compaction was determined using the Cone index readings which were
taken with a hand held 13-mm diameter, 30 ° cone tip penetrometer (Carter, 1967) at soil surface
of each plot. The soils were sampled to determine their properties during the months of October
(2003), April (2004) and June (2004) to represent the planting time, middle and end of wheat
growth, respectively. The dry weight of roots per plot was measured at harvest.

15. 15
Irrigation Scheduling in Tobacco
Soil-plant-water relationships treats those physical properties of soils and plants that affect the
movement, retention, and use of water and soil must be considered in designing and operating
conservation irrigation systems. But he must also have a working Imowledge of all soil-plant-
water relationships in order to plan efficient irrigation for particular crops grown on particular
soi13 and to adjust the design to various conditions. This general knowledge also enables him to
assist an irrigator in managing the system efficiently.
1.Materials and methods
1.1 Experimental site
Pot experiments were conducted in a canopy at the Xiuwen Irrigation Test Central Station (26450
to 27120N, and 106220 to 106530E) in Guizhou Province in southwest China. Guizhou Province
is a region with typical karst landforms consisting of relatively low mountains and hills. The study
area has a subtropical monsoon humid climate, with an average annual air temperature of 14.6C
and annual precipitation of 1 235 mm. The mean annual relative humidity is 77%, the annual
sunlight is 1 021.5 h, and the frost-free growing season is 270 d per year. The experiments were
performed on a plowed soil layer consisting of loess soil with an organic matter content of 33.69
g/kg, total nitrogen of 2.2 g/kg, total phosphorus of 0.3 g/kg, total potassium of 24.87 g/kg, dry
density of 1.38 g/cm, and pH value of 7.0. The field capacities were 37.3%, 35.7%, and 33.6% for
different soil layers at depths of 0e10 cm, 10e20 cm, and 20e40 cm, respectively.
1.2. Experimental design
Pot experiments were conducted in 2006 and 2007 to investigate the tobacco water requirement
and the effect of water deficit on tobacco yield. To avoid the effect of precipitation, experiments
were carried out in a canopy with two open ends. The canopy was 30 m long, 10 m wide, and 4 m
high. To facilitate the experiment, tobacco was planted in plastic pots with a height of 40 cm and
a diameter of 35 cm. Tobacco seeds (Yun 85), the most popular cultivar in the region, were
transplanted on April 25, 2006 with five various treatments (treatments 1 through 5) and on May
1, 2007 with nine various treatments (treatments 6 through 14). Treatment 5 was considered the
conventional treatment. A randomized complete block experimental design with all the treatments
described above and 15 repetitions for each treatment were adopted.
In contrast to the common classification of tobacco growth stages, including the elongatio n,
vigorous growing, and mature stages, the whole growth period was classified into four growth
stages in the experiments, including the rejuvenation, group, vigorous growing, and mature stages.
In order to investigate the water requirement under various water stress levels, lower limits of soil
water content at different growth stages were set for the 14 treatments involved in this study (Table
1).
1.3. Observation and calculation methods

16. 16
Daily climatic parameters, mainly including precipitation, wind speed, temperature (maximum,
minimum, and average), sunshine duration, relative humidity, and pressure, were measured at the
Xiuwen Weather Station adjacent to the experimental site. Soil moisture was monitored at 8:00
am every day with a time-domain reflectometer (TDR; soil moisture meter, USA). The TDR was
installed at different flow depths: 0e10 cm at the rejuvenation stage, 10e20 cm at the group and
vigorous stages, and 20e40 cm at the mature stage. In pot experiments, water was discharged into
pots through point-source irrigation until the soil moisture reached the lower limits of soil water
content determined in Table 1. In this study, the water requirement intensity was defined as the
ratio of the water requirement to the corresponding duration of time, and the water requirement
module was defined as the ratio of the water requirement of a certain period of time to the water
requirement throughout the growth period. The tobacco water requirement (ETt) at each growth
stage was calculated with the field water balance equation:
ETt ¼ W0t Wt þPt þIt St þKt ð1Þ
where the subscript t means the growth stage t; W0t and Wt are the water contents in the soil
profile at the beginning and end of stage t, respectively; Pt is the precipitation; It is the amount of
irrigation water; St is the percolation; and Kt is the groundwater recharge. Since the experiments
were conducted in a canopy, the values of precipitation, percolation, and groundwater recharge
were set as zeros.
2. Results and discussion
2.1. Variation of tobacco water requirement
The tobacco water requirement throughout the growth period in pot experiments ranged from
159.00 to 278.90 mm (Table 2), while it ranged from 400 to 600 mm in field production (Chen et
al., 1995; Gao, 2006; Li et al., 2008), much higher than in pot experiments. He (2004)
demonstrated that the tobacco water requirement was 45 mm at the elongation stage in a pot
experiment, while it was 58 mm in field production. In pot experiments, the tobacco water
requirement ranked the highest at the mature stage, followed by those at the group/vigorous
growing and rejuvenation stages, while it ranked the highest at the group stage in field production,

17. 17
followed by the tobacco water requirement at the vigorous growing stage (Wang et al., 2007; Chen
et al., 1995).
2.2. Variation of tobacco water requirement intensity
Crop water requirement intensity can be affected by the water requirement, growth stage, and
metabolism. The average water requirement intensity of tobacco throughout the growth period in
pot experiments was 1.39 mm/d, which was lower than the value of 2.93 mm/d in field production
(Li et al., 2008; Jiang et al., 2011). The water requirement intensity followed by those at the mature,
group, and rejuvenation stages. These results were consistent with those in field production.
low water requirement intensity was attributed to the small size of plants at the rejuvenation stage.
As tobacco plants grew, the water requirement intensity at the group stage increased, ranging from
0.69 to 1.48 mm/d. The vigorous growing stage was a period of quick growth, at which the water
requirement intensity reached the highest level, ranging from 0.97 to 2.56 mm/d. This finding was
consistent with Wang et al. (2007) and Hajiakbar et al. (2006). Physiologicalmetabolic activity
decreased at the mature stage, at which tobacco leaves were picked. Thus, the water requirement
intensity declined, ranging from 0.76 to 1.88 mm/d. However, the average water requirement at
the rejuvenation and group stages were more than 1.5 mm/d in field production, and the values
were greater than 4.0 mm/d and 2.0 mm/d, respectively, at the vigorous growing and mature stages
(Chen et al., 1995; Hajiakbar et al., 2006).

18. 18
2.3 Variation of tobacco water requirement module
The water requirement module of tobacco at the mature stage in pot experiments ranked the highest
under protected cultivation, followed by those at the group/vigorous growing and rejuvenation
stages. The water requirement module at the group stage in pot experiments was close to that at
the vigorous growing stage (Table 4). However, the tobacco water requirement module at the
vigorous growing stage ranked the highest in field production, followed by those at the mature and
elongation stages. Sun et al. (2000) found that the tobacco water requirement modules at the
elongation, vigorous growing, and mature stages were 20.0%, 50.0%, and 30.0%, respectively.
Gao (2006) found that these values were 16.6%, 50.0%, and 33.4%, respectively. Cai et al. (2005)
also found that these values ranged from 17.3% to 22.3%, 42.7% to 46.1%, and 35.0% to 36.8%,
respectively. Hajiakbar et al. (2006) measured these values as well, obtaining ranges of
16.0%e20.0%, 44.0%e44.6%, and 34.8%e37.0%, respectively.
2.4. Effects of water deficit on tobacco water requirement
Water deficit at the group, vigorous growing, and mature stages affected the tobacco water
requirement to different extents. Compared with the conventional treatment, the water
requirements throughout the growth period with water deficit occurring at the group stage
decreased by 37.3 mm and 39.1 mm under treatments 12 and 9, respectively; the values with water
deficit occurring at the vigorous growing stage decreased by 39.3 mm and 62.0 mm under
treatments 13 and 11, respectively; and the values with water deficit occurring at the mature stage
decreased by 14.10 mm and 29.27 mm under treatments 4 and 3, respectively. The corresponding
water requirement intensities throughout the growth period decreased by 0.27 mm/d and 0.29
mm/d under treatments 12 and 9, by 0.29 mm/d and 0.42 mm/d under treatments 13 and 11, and
by 0.09 mm/d and 0.18 mm/d under treatments 4 and 3, respectively. The influence of soil water
stress at the vigorous growing stage on the water requirement and water requirement intensity of
tobacco was the most significant, followed by that of soil water stress at the group and the mature
stages.

19. 19
Conclusion
The objective of this study was to develop appropriate tillage and farm yard mulching systems for
conserving water and soil with the aim of improving the grain yield of wheat (Triticum aestivum
L.) of the cultivar Sardary. Three plowing treatments (MP, CP, and DP) and three FM applications
(no application, mixing with soil and application as mulch on soil surface) were employed. From
the results it can be concluded that:
ter content in the soil profile and
decrease runoff and soil loss. However, the yield was not economical due to the effect of ice
damage on the winter wheat seed.
systems increased grain yield. The
mulched DP had the highest yield of wheat among the treatments.
tion, soil water content and yield in the conventional tillage system
(MP).
ge systems and at the same time conserves water
and soil. Therefore, it is a good strategy to be adopted not only with the conventional tillage system
but also with the conservation tillage system which is usually associated with low yield.
The tobacco water requirement throughout the growth period in pot experiments ranged from
159.00 to 278.90 mm, a range lower than that in field production. The tobacco water requirements
at the rejuvenation, group, vigorous, and mature stages ranged from 5.90 to 7.60 mm, 33.80 to
72.60 mm, 23.30 to 66.50 mm, and 36.20 to 142.84 mm, respectively. The tobacco water
requirement and water requirement module at the group stage were almost equal to those at the
vigorous growing stage in pot experiments. At these two stages, the tobacco water requirement,
water requirement intensity, and water requirement module ranged from 23.3 to 72.6 mm, 0.69 to
2.55 mm/d, and 14.65% to 33.09%, respectively.
The tobacco water requirement intensity in pot experiments showed the same pattern as that in
field production. The water requirement intensity at the vigorous growing stage under protected
cultivation ranked the highest, followed by those at the mature, group, and rejuvenation stages.
However, the average tobacco water requirement intensity was 1.97 mm/d at the vigorous growing
stage in pot experiments, with an obvious reduction of 2.04 mm/d as compared with that in field
production.
The tobacco water requirement at the vigorous growing stage was the most sensitive to water stress
in pot experiments at the study site. Serious water deficit at the vigorous growing stage can cause
a significant aftereffect on the tobacco water requirement. Tobacco in pot experiments should not
undergo severe water stress at the vigorous growing stage and at three continuous growth stages.
Results showed that the lower limit of moderate soil water stress at the vigorous growing stage
was 65% of the field capacity.

20. 20
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