Figure 1: Green vs Desert in the Ica-Valley (Google Earth, 2016).
Julia Beutler (10802789) Dante Follmi (10712844) Olaf de Haan (10728570) Noud Egberts (10770925) Tutor: Anneke ter Schure Expert: Andres Verzijl
Relieving Water Stress
in the Ica-valley: an
interdisciplinary
approach to create a
sustainable
water-balance
December, 2016
Abstract
A huge share of the water intense asparagus cultivation is situated in one of the driest areas in the world: the Ica-Valley, Peru. This has major influences on both the environment and interrelations between different actors operating in the valley. The aim in this research is therefore to construct a strategy in terms of a sustainable water balance regarding asparagus cultivation. An interdisciplinary approach is required, in which with the overarching concept of sustainability and the scenario analysis both the social and environmental perspectives are included. Using Social Network Analysis and AquaCrop, it came forward that drip irrigation, plastic mulch and water use of 150 to 300 mm needs to be included and that the ANA should create more power and responsibility to implement these strategies properly by addressing both large agro-exporters and small to medium sized farmers. This would in turn lead to a sustainable water balance in the Villacuri-aquifer. The constructed scenario ‘Government intervention and Good irrigation practises’ should be pursued, as it includes stricter regulation for equalizing the power and addressing the techniques and with education + cooperation the knowledge is shared amongst all stakeholders.
Contents
1. Introduction2. Theoretical Framework 3. Methods
3.1. Social Methods: Social Network Analysis and Cognitive Mapping 3.2. Environmental methods: The Aquacrop Model
3.3. Hydrology 3.4. Scenario analysis 4. Results 4.1. Stakeholder analysis 4.2. Aquacrop 4.3. Hydrology
4.4. Integration of results: scenario analysis 5. Conclusion
6. Discussion & future recommendations 7. References
8. Appendix
1. Introduction
Peru is the second largest asparagus-producing country in the world (FAO, 2013). The Province of Ica, in the southwest of Peru, is responsible for 95% of the total asparagus production of the country and provides labor to 65000 people (Hepworth et al., 2010; Rios, 2007). Since Peru is close to the equator and has arid climate conditions, there is a small temperature and daylight length difference per season. Therefore, Peruvian asparagus can be harvested all year (Meade, 2011). This is a huge advantage over the asparagus cultivation in temperate climates, where harvest is only possible from April until June (Knaflewski, Kucharski & Krzesinski, 1997). The cultivation requires a lot of water, while the Ica-Valley faces one of the most serious drought problems of the world. (Bullock, n.d.). This in turn has influences on the multiple actors related to the water issue within the valley.
For the environment and the well-being of Icas inhabitants it is important to construct a sustainable water balance of the asparagus production. Therefore, the challenge is to construct a system whereby the asparagus could be cultivated in a sustainable manner. Asparagus crop growth is directly linked to water usage, which leads to the research question: What strategy in terms of water balance is most sustainable in the Ica-valley, regarding asparagus cultivation?
The research question is limited to the Ica-Valley, in order to specifically focus on the sustainable issues in this area, instead of including other areas and their environmental factors, communities and authorities. This would in turn result in a more complex situation; increasing the scope and thereby not maximising the opportunities of addressing the issues in the Ica-Valley properly.
To obtain in-depth knowledge of the complexity of the subject, the strategy of this research is interdisciplinary. Sustainability includes both the environment and the society, therefore the problem can only be addressed with interactions and on the interplay of these disciplines. The two disciplines, earth sciences and human geography are both contributing to get an
interdisciplinary understanding of the water problem in the Ica-valley. In the research the redefinition integration technique is used. The aim of the research is to search for an optimal sustainable strategy, which is the overarching concept from which conclusions are drawn and recommendations formed. The optimal sustainable water-balance strategy originates from the concepts of the two disciplines and hence creates a common meaning and vocabulary to address a solution for current water usage in the Ica-valley. This integrated approach could in turn be applicable in other areas with water related issues.
In the first section relevant theories and concepts will be elaborated. Afterwards a description of the used methods will be given, including the Aquacrop model in generating quantitative outputs in order to asses the requirements for a sustainable-water balance strategy, followed by the stakeholder analysis methodology and a literature review. Subsequently, the results from the aquacrop models are presented in order to examine an environmentally sustainable water-balance strategy. Furthermore, the relevant stakeholders which came forward from the stakeholder
analysis are illustrated and their stakes presented. Consequently the results from both disciplines will be integrated and therefore a new framework will be presented, using scenario analysis.
2. Theories and concepts
In this interdisciplinary research various concepts and theories of both human geography and earth science will be used. As the objective is to propose a strategy in terms of a sustainable water balance, both disciplines need to be well integrated in the concept of sustainability: thus social and environmental sustainability need to be combined in an overarching concept. However there are some key-concepts that can be divided between the two concepts (social and environmental). These are specific, contributing to this research, and are discussed below.
In this research we use, partly, McKenzie’s definition of social sustainability (2004) which states that: ‘’Social sustainability occurs when the formal and informal processes, systems, structures and relationships actively support the capacity of current and future generations to create healthy and liveable communities. Socially sustainable communities are equitable, diverse, connected and democratic and provide a good quality of life’’.
This definition of social sustainability is useful since it both shows how social sustainability is reached and what the characteristics of social sustainability are. The social sustainability concept used in this research has three key-concepts, extracted from McKenzie (2004): ‘Equality between stakeholders’, ‘Limit corruption’ and ‘Connected stakeholders’. These key-concepts are extracted, as they are most relevant in the research and emphasize the social issues in the valley . Eventually these concepts are integrated in the results.
Definition of environmental sustainability: ‘’Environmental sustainability refers to consuming natural resources at a rate below the natural regeneration or to consuming a substitute, generating limited emissions and not being engaged in activities that can degrade the ecosystem’’ (Kleindorfer, Singhal, & Wassenhove, 2005).
Also for environmental sustainability there are three key-concepts, which specify the citation above and account for this particular discipline and research: ‘Limitation of water use from wells’, ‘Decrease of evaporation’ and ‘Limit salinity’. When the key-concepts of both definitions of sustainability are combined, a sustainable water balance strategy can be defined as: a strategy which limits water use and water quality deterioration while treating and paying equal attention to all stakeholders. More specifically, water use can be limited by decreasing water use from wells and evaporation along with limiting salinity.
This research also focuses on the water balance and salinity. In relation to the water usage in the Ica-valley, water excreted from aquifers is bigger than the inflow of water into the aquifer and can be determined as unsustainable. Furthermore the ecosystem can be unbalanced due to high salinity rates, by using water from saline sources (Hepworth et al., 2010).
A research on integrated water management strategies by Thomas & Durham (2003) emphasised greatly on the importance of the stakeholder dimension in water management
strategies. The stakeholder dimension should receive a lot of attention especially in the decision-making process, because otherwise it is difficult to include the conflicting interests of the different stakeholders (Thomas & Durham, 2003).
Important in the assessment of stakeholders is analysing the relative importance and strength or power of stakeholders. The stakeholder’s power relates to the power of the stakeholder to affect or be affected by other stakeholders. The power of stakeholders results from different characteristics like capital and other resources (Hanneman & Riddle, 2005). Besides the relative power of stakeholders being determined by the resources, it will also be determined by the number of connections a stakeholder has with other stakeholders and the relative strength of these connections (IIED, 2005). The reason that the number of connections partly determines the stakeholder’s power is simply because more connections means more choice and opportunity which makes the stakeholder less dependent on another (Hanneman & Riddle, 2005).
3. Methods
In this section the, diverse, methods of our interdisciplinary project will be discussed. Firstly the social methods will be described in order to create a basic framework wherein the importance of the environmental methods, and thereby integration, will be addressed.
3.1 Social Methods: Social Network Analysis and Cognitive Mapping
For constructing efficient policies it is important to create a clear guidance of how the stakeholders are organized. Studies have shown that understanding the social relations; power and thoughts of stakeholders within a system could enhance policy and decision-making (Scott 2013; Kitchin 1994; Saint Ville 2013). The knowledge of which stakeholders are involved and what their discourses are will be extracted from existing literature and case-studies. Besides, literature regarding water rights and power relations will be analysed to create a proper background of some assumptions which will be made regarding the Ica-Valley.The information gathered will be analysed on the basis of Social Network Analysis (SNA), creating a clear overview and method of improving the efficiency of the network. With SNA the actors with the most influence within the system can be determined by counting the amount of relations (ties) between actors and analysing their opportunities and constraints (Scott, 2011; Hanneman, n.d.; Granovetter, 1973). Consequently, actors who face the fewest constraints and have the most ties are in a more favourable position in the network and have a greater influence on the other actors (more power). Furthermore, it will possibly be important to create more ties between the stakeholders to enhance the data flows. Within the mind set of Cognitive Mapping, the discourses regarding the concept of sustainability of the various stakeholders will be analysed. It is generally thought that if the various representations and thereby actions are understood, the deficiencies within a system with multiples representations can be exposed and hence used for organising a collective plan to address the issue (Kitchin & Freundschuh, 2000).
3.2 Environmental Method: The aquacrop model
The reason why the Aquacrop model is used, is because modeling is probably the best way of predicting crop behavior for a period of time (Portmann et al., 2010). Compared to other models, that are solar- or carbon driven, Aquacrop is water driven (Panday, 2014). The assumption is made that there are different, contesting discourses of the stakeholders regarding asparagus cultivation. Subsequently, an underlying assumption is that these contesting discourses are generated due to the water scarcity within the Ica-Valley. It would therefore be very useful to propose a strategy in which the amount of water for cultivation could be limited. This should both be addressed in the social section together with equality, corruption and connection, as explained above, and in the environmental section wherein the exact possibilities of water use limitation will be investigated. Seventeen different scenarios are run with the model (Appendix, Table A1). Each with different input parameters; as discussed below. The output parameters are denoted in the Appendix, Table A2.
Input Parameters
Climate
For climate we use specific climate data that correspond with the city of Lima. This default data corresponds with the Ica-valley and has equal rainfall-, ETo- (reference evapotranspiration), Temperature- and CO2 -levels. However due to the Humboldt current Lima has slightly more rain than the city of Ica: 28 mm compared to 24 mm. This is due to the generation of fog that precipitates in the coastal area of Lima (WorldWeatherOnline, 2016; FAO, 2011). However there are places within the ica-valley where rainfall is even lower than 1 mm annually (Hepworth et al., 2010). Still the decision is made to use the default climate of Lima, because there will be still reliable outcomes for our analysis. Drainage to aquifers is negligible, because precipitation is too low. The average temperature in Ica is around 21 degrees and for Lima 21.5 and they show similar patterns on annual scale. Furthermore, the reference evapotranspiration that stands for the evaporative demand from the atmosphere (i.e. a hypothetical grass crop), is varying from 2 mm/day to 5 mm/day, with peaks in December and January that reach 6 mm/day (FAO 2009). Furthermore CO2 -levels are derived from the Mauna Loa on Hawaii and represent global CO2 -levels. This is based on increasing concentrations and is currently around 400 ppm.
Crop
In this research a default maize crop is used as reference crop for asparagus. This crop is used because no reliable asparagus crop input data could be derived. The default maize crop is chosen instead of other default crops because:
1. Maize and asparagus use almost the same amount of water. Maize uses on average 500 to 800 mm water in one life cycle in arid regions (FAO, 2015). In the Ica-valley an average of 750 mm for asparagus is used(Rendón, 2009).
2. This is also denoted in the RAW (Ready available water) of both crops. RAW is calculated by multiplying the average fraction that can be depleted from the root zone (p) times the TAW
(Total available soil water). The depletion fraction for maize (0.50) and asparagus (0.45) is comparable (FAO 1998). Which means that both crops have similarities in water uptake. 3. The life cycle of both plants is comparable. Maize takes approximately 150 days from
germination to harvest and asparagus takes 180 days in the Ica-valley (FAO, 2015) 4. The crop coefficient (Kc), that predicts the evapotranspiration, is for both crops almost
equal. Asparagus has a Kc of 0.95 compared to maize with a Kc of 1.15 (FAO, 1998). Which means they have both comparable evapotranspiration regimes.
Irrigation
Appendix (Table A1) shows seventeen scenarios in order to understand what crop behaviour would do under different types of irrigation, irrigation quantity, surface wetted and salinity (‘Mulches’ is discussed in the ‘Field’ subparagraph). The quantity (mm/crop cycle) shows the amount of water irrigated in the model, whereby 750 mm is the standard that is commonly used in the Ica-valley (Rendón, 2009). We chose two types of irrigation to measure both drip- and border irrigation. Large agro business in the ica valley make use of drip irrigation in order to decrease water usage, compared to small-medium size farmers that make use of border irrigation originated from non-groundwater resources (Hepworth et al., 2010). According to the Aquacrop model, drip irrigation wetted the surface for 10% on average and in the case of border irrigation 100% is wettened. Small to medium sized farmers believe that aquifers are recharged due to their border flooding technique. Stagnating water on the soil surface will slowly percolate towards groundwater and refill aquifers (Hepworth et al., 2010). Therefore scenarios 11 to 15 are included in this research. The output of the model can tell us the amount of mm water drained towards the aquifer per hectare and discusses the advantage of border irrigation compared to drip irrigation.
Salinity is an input parameter that is measured by the electric conductivity in deciSiemens per meter (dS/m). Only in scenario 1, 2 and 11 water has a salinity of 0,4 dS/m. This is the type of electric conductivity of the water from the Ica river, which is mainly used by small farmers (CERES, 2000). This parameter is added to measure the effect of salinity on plant growth in one growth cycle. Field
In order to decrease evaporation from the soil, plastic mulch could be used. In this research this kind of mulch covers 95% of the soil surface and is applied in several drip-irrigation scenarios. This technique is not implementable with border irrigation, because this remains technically too difficult to apply. Due to the physical boundary (i.e. the plastic mulch), water cannot percolate into the soil. Soil & Groundwater
The soil that is commonly found in the Ica-valley are Arenosols (ISRIC, 2005). These soils consist of sand or loamy sand and has no or limited horizon formation properties. Therefore a default sandy soil of four meter with no horizons is used as input parameter. This commonly found soil in the Ica-valley is also the soil where most asparagus are cultivated on (Hepworth et al., 2010). The sandy soil has compared to other soil a high hydraulic conductivity (Ksat): 1500 mm/day. This means that water can easily be transported through the soil and can percolate easily downwards. Furthermore the
groundwater level in the Ica-valley is on average 37 meters below the surface, so there is limited groundwater available for plant growth (ANA, 2008).
3.3 Hydrology
To reach environmental sustainability one of the key-concepts ‘limitation of water use from wells’ could also indicate that groundwater inflow and outflow should reach an equilibrium. To indicate to what extend this system is imbalanced, a literature research is conducted. The main focus will be on a case study of the Ica-Villacuri aquifer, which is connected to the main-Ica aquifer and plays a key-role in asparagus cultivation in the Ica-valley (Hepworth et al., 2010). Finally this case study plays a role in the scenario analysis.
3. 4 Scenario analysis
In order to integrate the data from both Aquacrop, hydrology and the stakeholder analysis, a scenario analysis is conducted. A scenario analysis is a tool, which is useful to test and define strategies before implementing them in practice. According to Kosow & Gassner (2008) a scenario can be defined as:
‘’a description of a possible future situation, including the path of development leading to that situation. Scenarios are not intended to represent a full description of the future, but rather to highlight central elements of a possible future and to draw attention to the key factors that will drive future developments. Many scenario analysts underline that scenarios are hypothetical constructs and do not claim that the scenarios they create represent reality’’. (Kosow & Gassner, 2008, p.1).
The use of scenario analysis in regards to this research has multiple benefits. It has the ability to transcend disciplines and, secondly, it takes uncertainty into consideration (Laurent et al, 2015). The ability to transcend disciplines comes from the fact that when a scenario analysis is made, the different drivers in the system needs to be considered. The identified drivers have an impact on the system from different categories; in this case society and environment. Besides transcending disciplines it also helps to incorporate disciplines into a narrative (Laurent et al., 2015). The second benefit of scenario analysis is the ability to take uncertainty into account. First the key uncertainties are explored which in this case are the degree of social sustainability and the degree of
environmental sustainability. In exploring the uncertainties a dialogue is taking place between the researchers of the different disciplines which can again help to integrate disciplines.
The future scenarios are developed through a technique called the creative-narrative scenario technique (Kosow & Gassner, 2008). This scenario technique is characterized by a creative
and intuitive way of generating scenarios. This technique is intuitive in that it allows the intuition to play a part in defining the possible futures and defining the uncertainties. Since scenario analysis is about constructing and analyzing future scenarios, assumptions have to be made, but there is more than just a ‘gut feeling’ playing a role in constructing these scenarios. These scenarios are based on the results and contextual knowledge of the Ica valley.
Figure 2 - Scenario analysis (authors).
4. Results
4.1 Stakeholder Analysis
In this section a comprehensive overview is given of the characteristics and objectives of the different stakeholders and their interplay on the basis of SNA. It is important to notice that the focus in this research is on a limited amount of actors, which are considered as most important actors with regards to constructing a sustainable strategy within the Ica-Valley. Thereby, some actors are elaborated under the supervision of other stakeholders, as their motivation is partly the well-being of these particular actors.
Figure 3 - Social network of relevant stakeholders within the Ica-Valley, their interrelations and distribution of power and connectivity. Thicker lines means stronger ties (Authors).
Agro-exporters
Based on the amount of ties, it does not come forward that the agro-exporters have the most power in the system: they have the same amount of ties (relations) as the regional and national authorities (three). However, based on the fact that they have one of the most ties in the system and, as in this section comes forward, most economic capital and knowledge of techniques, it is assumed that the agro-exporters have the most power within the social network.
The agricultural land in the Ica-Valley is predominantly farmed and/or owned by large agro-export companies. There are currently 29 agro-export farms with 300 to 1500 hectares of agricultural land. In comparison, 22377 small to medium size farmers, with 1 to 100 hectares of land, are at play (Endes 2008, conducted from Progressio, 2010). These businesses have major contributions in the global agricultural industry as their crops, mainly asparagus, providing the export markets of Peru (Bullock, n.d.).
The agro-exporters their agricultural land is mainly situated in the downstream area of the Ica River. They managed to access groundwater by controlling existing wells and constructing new wells in new bought land (Dessaro, 2015). The various agro-exporters can be described as a heterogeneous group with the same interests and objectives. Subsequent to their power in economical terms, they managed to retrieve power in political terms. The discussed power is deeply embedded in the region's political system, resulting in an informal licence to discourse their objectives: generating the greatest market-share and unregulated access to groundwater aquifers (Dessaro, 2015). In turn, it is appealing for government bodies to support the large agro-exporters as they have the knowledge
and innovation techniques for efficient irrigation, monitor the water water resources and invest in infrastructure. As they are dependent on the groundwater, most agro-export companies are concerned by the water depletion, as it will affect their profitability. The majority of agro-exporters gathered to form a collaboration to, implicitly, join their political and economic power to influence governmental bodies in order to avoid groundwater regulations (Dessaro, 2015). Nevertheless, if critical levels are reached (empty aquifer or too expensive to drill) they are easily able to invest in less water critical areas elsewhere, as it is assumed that they are not culturally or historically rooted in the Ica region. This would have huge affects on the social-economic situation in the Ica-Valley. It will result in high unemployment rates, as the agro-exporters give labour to many local citizens. Besides, a huge capital of knowledge would disappear. However, in various case studies (Bullock, nd. Progressio, 2010), it is described that some agro-exporters actually are ‘emotionally’ aware of their independency and thereby dependency of their employees. One company stated that ‘we will do what we can to get the water right to support the 4000 poor families in Ica by providing jobs’ (Progressio, n.d.). Nevertheless, if the water level will reach a real critical level it will be questionable whether these agro-exporters will still support their previous statements.
Small and medium sized farmers
Within the social system, the small and medium sized farmers are only connected with the regional government, which is in turn highly influenced by the large agro-exporters. In contrast with large agro-exporters and their farms; small farmers tend to be above groundwater users (rivers and lakes) and their cultivated grounds are predominantly located upstream. In 2008 a prohibition on new wells was set to increase taxes and decrease the consumption of groundwater (Dessaro, 2015). Consequently, multiple small farmers could not afford these taxes and were forced to sell their wells to the agro-exporters; others are drilling to groundwater illegally (Bullock, n.d). Nevertheless, the majority is currently completely dependent on aboveground water as underground water is not accessible for them (Bullock, n.d). Besides, they do not have the information to repair old or poor wells (Progressio, 2010). In this manner, besides the access of water, economic and knowledge capacities are also a limiting factor (Azimi et al. 2012).
It is presumed that when the aquifers are empty, the agro-exporters will transform to aboveground users before investing in other, water richer, areas. The case study of Progressio (2010) observed mistrust and fear from small and medium sized farmers to agro-exporters and the government who supports them. It is assumed that they do not have the ability and willingness to migrate to other areas as they are culturally and historically rooted in the Ica-Valley. Eventually, that have to confront the potential degrading environment.
The National Water Authority and their subsidiaries
Beforehand, the authors presumed that the National Water Authority (ANA) would have the most power in the system as they can create policies and restrictions. However, as will be explained, due to corruption, lack of capital and bad leadership the influence is much smaller, in favour of agro-exporters.
The ANA is a governmental agency within the ministry of agriculture and irrigation. It is the highest authority on water policy in Peru, thus all the political, water related, decisions have to be approved by the ANA or the subdivided regional authorities: the AAAs and hence subdivided local water authorities: the ALAs (Bullock, nd). In theory, they are responsible for monitoring data regarding water levels, flows and the amount of wells (Bullock, nd). The AAAs and ALAs are not involved in the decisionmaking process.
In 2009 the first policy was organised which sought to construct the water sources as participatory spaces, including both state coordination and a decentralization of the public water management to regional and local level (AAAs and ALAs) (Dessaro, 2015). The framework, which provided the background of the above actions, is the Integrated Water Resource Management paradigm. Within this paradigm efficient, equitable and a sustainable development is central (Durham & Thomas, 2003). The development to a more sustainable strategy had, though, some constraints. Because the production of small farmers is too inefficient for the global export market, the authorities mainly focused on supporting the large agro-exporters for generating more revenues (Dessaro, 2015). Here it comes forward that power is extremely important in constructing a certain social sustainable landscape: a social actor has a disproportionately greater share of waterpower than other actors in the Ica-Valley. Small farmers and local people state that some constructed policies are good, however, the implementation is too limited as a result of a lack of capital, staff and thus power. If authorities expose illegal wells of agro-exporters, they are able, due to their power, to undermine the authorities (Progressio, 2010). In contrast, Illegal wells of small farmers will be ‘shut down’ much easier, resulting in more inequalities in the region. Besides, an engineer from an agro-exporter states in the case study by Progressio (2010) that whilst there are certain restrictions of the amount of water withdrawal, the authority never controls or checks this. Only the producers are aware of the precise information on the aquifers and wells, as they do have monitoring applications.
Consequently, ANA is left aside. In fact, the ANAs ‘approximate’ number of the amount of informal wells in periods of water regulation has increased. In 2010 only 29 per cent of the wells were legally registered with the ANA (Bullock, nd).
ProInversion
ProInversion is an independent department in the government, which is responsible for generating private sector investments in Peru (Bullock, nd). In 2008 they started to interest in the Ica-Valley with regards to the drought problems. Currently, ProInversion is collaborating with the ANA and potential investors to research the feasibility of some large-scale projects in counteracting the drought issues. Already two private firms have shared their interest and willingness to finance the investments in a public-private collaboration (Bullock, nd).
4.2 Aquacrop
After the input, discussed in the method section, was run in Aquacrop, several correlations can be distinguished whenobserving the outcome (table 1). In the following paragraphs these correlations will be discussed. A statement derived from these correlations, which will also be mentioned in the
conclusions, follows the correlations. The observed relationships are mainly linear. All Aquacrop outcomes are also added to the appendix (part B) as screenshots.
Mulch
There appears to be a relationship between mulch and evaporation. Whenever mulch is applied, the evaporation tends to be slightly below 50% of the evaporation with the same amount of irrigation water, but without the mulch. This does, however, change when less water is irrigated, as can be witnessed with 150 mm and 100 mm of irrigation water. This change in effect of mulch on evaporation is visualized in the figure below. Here the percentages of evaporation reduction are both around 40%. This relationship is also visible when comparing the mulch/no mulch results with the ET water productivity. This is logical because the ET water productivity is partly determined by the evaporation.
Figure 4 - The effect mulch has on Evaporation Irrigation type and amount
Another relationship found was between drip irrigation and border irrigation. According to the data, drip irrigation is more water efficient than border irrigation, which is also depicted in figure 5. The drip irrigation used in this comparison is drip irrigation without mulch, because border irrigation is also without mulch. Drip irrigation causes an evaporation less than one third of that of border irrigation. This proportion is even far less when 150 mm is irrigated. The percentage found here is 15%. But there are also several other parameters in table 1 that might be a factor in the latter case. For instance, the canopy cover of the 150 mm border irrigation is severely reduced, while the 150 mm drip irrigation is not. This results in very different water uptake by the plant which should be included when conclusions are drawn. The relationship can also be seen when looking at the ET water productivity because of the same reasons discussed in the previous paragraph.
750 mm of irrigation water seems to be more than is required for maximum yield. This applies also for 500 mm. When compared to 300 mm , both amounts differ less than 0.1 ton/ha in yield. This is such a small difference that it is negligible. Moreover, the ET water productivity is the same with all three irrigation quantities, as is the ratio and canopy cover. There is a drop in all mentioned outcomes when 150 mm irrigation water is applied. Therefore, the most efficient quantity of irrigation water seems to be between 300 mm and 150 mm. This is also visually explained in figure 5. According to the findings in Aquacrop, border irrigation causes less drainage to the ground water than drip irrigation. How much less is consistent with irrigation of 750 or 500 mm. Drip irrigation drains in both cases about 20 mm more water to the aquifer. With 300 mm this amount has declined to 7.5 mm. When less than 300 mm is applied for irrigation, both irrigation techniques show no drainage. This correlation between border irrigation and drainage to groundwater is not in line with the literature. Hepworth et al. (2010) for instance, write about how medium to small sized farmers believe their border irrigation refills the aquifer. According to the findings of table 1 these farmers are wrong. There is however, still a positive correlation involving drainage to the aquifer found in the results. According to the Aquacrop simulations, more irrigation water causes more drainage to the aquifer. This is also why border irrigation causes less drainage; more irrigation water is lost due to evaporation.
Figure 5 - The effect that each irrigation type has on evaporation Salinity
As for the added salinity factor, the mass of salts that ultimately ended up in the soil is depicted in table 1. What stands out is that border irrigation results in slightly more salt accumulating in the soil, compared to drip irrigation. This could be because of the higher evaporation factor, causing an increase in the salts precipitated, meaning that the plants absorb less of the salts. This also means that drip irrigation causes slightly more leaching. What is not depicted in table 1 is if the resulting salinity is harmful to the maize plant. With both amounts of salinity, Aquacrop indicates that there is
no possibility of salinity stress to the maize plant. Keeping in mind that asparagus has a far higher salinity tolerance than maize, there will definitely be no harm done to the asparagus plant, salinity wise (FAO, 2012). The Aquacrop model runs however, just for one year. So the amount of salts precipitated after several years, is not captured in this report.
Concluding from the paragraphs above, the highest yield per hectare would be achieved by irrigating high amounts of water (750 mm) using drip irrigation techniques and plastic mulch (scenario number one). This is however not the most sustainable. A more sustainable way can be reached, resulting in just a small amount of less yield per hectare, by applying less water to the field. This amount would lie somewhere between 300 mm and 150 mm per hectare. If this amount of irrigation water is combined with drip irrigation and plastic mulch, the most water efficient way of agriculture is reached.
Drainage
Drainage is positively correlated with the amount of irrigation. The more irrigation is applied, the more water is drained to the groundwater below. When drip irrigation is applied the limit of water drainage is presumably reached just after 300 mm of water, because 300 mm results in a small amount of drainage and 150 mm always provides zero drainage. This applies however, not to border irrigation. When border irrigation is used, this limit is reached between 500 mm and 300 mm. This is also visually explained in figure 6. Again, the no mulch scenarios are used, for the same reason as is applicable to figure 5. This difference in effect between the two irrigation types probably has something to do with the higher evaporation rate that border irrigation causes. If more water is evaporated, less water is left to reach the aquifer. Therefore, if more drainage to the aquifer is desired, drip irrigation should be applied.
Figure 6 - The effect the irrigation type and amount has on the drainage to the aquifer
Table 1 - The results from the 17 Aquacrop model runs, using the reference crop maize
Scenario Nr. Yield (ton/ha) ET* water productivity (kg/m3) Drained to groundwater (mm) Canopy cover Evaporation (mm) Ratio (%) Salinity (ton/ha) 1 13.080 4.63 449.4 Optimal 4.6 100 0.765 2 12.962 4.56 447.5 slightly less optimal 9.3 99 0.765 3 12.962 4.56 447.5 slightly less optimal 9.3 99 0
4 12.962 4.56 197.1 slightly less optimal 9.4 99 0 5 12.964 4.56 7.5 slightly less optimal 9.5 99 0 6 8.940 4.14 0.0 good 11.6 72 0 7 13.080 4.63 449.4 Optimal 4.6 100 0 8 13.080 4.63 199.1 Optimal 4.6 100 0 9 13.083 4.63 10.0 Optimal 4.5 100 0 10 9.266 4.28 0.0 good 4.7 74 0 11 12.960 4.19 426.8 slightly less optimal 34.1 99 0.769 12 12.960 4.19 426.8 slightly less optimal 34.1 99 0 13 12.961 4.18 175.8 slightly less optimal 34.8 99 0 14 12.946 4.16 0.0 slightly less optimal 36.6 99 0 15 5.636 2.77 0.0 bad 79.8 42 0 16 5.637 3.99 0.0 bad 17.1 42 0 17 6.022 4.30 0.0 bad 6.9 45 0
*ET is an abbreviation of EvapoTranspiration, the plants evaporation and transpiration combined.
4.3 Hydrology
According to Hepworth et al. (2010) there are different allegations about the water overuse of the Villacuri aquifer. According to other research, which is conducted by stakeholders such as the ALA, ANA or agro-exporters, an independent study by the World Bank seem to be most convincing. Moreover, they are not involved in the stakeholder debate.
The inflow of this aquifer is fed by river streams originating in the Andes mountains which end up in the lower (south) Ica-river. However, water originating from the upper streams in the Andes seems to be the only input, because there is a limited input of precipitation on the same geographical locations as the aquifer (Hepworth et al., 2010). Furthermore the outflow is mainly by agricultural practices in the valley.
According to the World Bank (2008), water overexploitation, from one of the main aquifers in the Ica-valley, has been 244 Mm3/year. This means a demand of 496 Mm3/year, compared to a recharge of 252 Mm3/year (Foster et al., 2008). As a consequence, to reach an environmentally sustainable water use, ideally only 252 Mm3/year should be used for anthropogenic purposes. This means that water use should be cut by 49%.
So when adapting towards a 150-300 mm irrigation pattern instead of 750 mm,
approximately 53% or even 73% less irrigation water is irrigated for asparagus cultivation. This could have major contributions to reach a water cut by 49% and create environmentally sustainable water use for asparagus in this particular case study.
4. 4 Integration of results: scenario analysis
As discussed in the theoretical framework a scenario analysis is used to integrate results and to obtain the best possible sustainable strategy for asparagus cultivation.
Scenario 1: Government intervention, good irrigation practices
In this scenario there is environmental sustainability represented by good irrigation practices and social sustainability as a result of well structured government intervention. Good irrigation practices such as 150-300 mm quantity and use of mulch and often drip-irrigation are the result of projects which educated both small and medium sized farmers and the larger agro-exporters. These educational programs also tried to connect small and medium sized farmers with large agro-exporters. These large agro-exporters have the knowledge and techniques that can help the small and medium sized farmers to use the water resources more efficiently. The money for these projects is generated by ProInversion which attracted private investors and also received money from the ANA. This increasing economic capital gives the local government the ability to better monitor and guide the production of asparagus. They pay for instance a lot of attention to the to the water levels of the aquifers, such as the Ica-Villacuri aquifer, which is fed mainly by river streams from the Andes. Use of water from this aquifer is under strict regulation so the outflow will not outnumber the inflow. In this scenario the problem is addressed from all levels.
Scenario 2: Development of sustainable crop cultivation, but growing gaps
between stakeholders
In this scenario the gap between stakeholders, especially between the large agro-exporters and small and medium sized farmers is growing. A positive aspect of this scenario is that there is development in sustainable crop cultivation. The reason that the gap between the agro-exporters and small and medium sized farmers is growing is because the AAA and ALA lack the capacity to
implement and thereby monitor the policies constructed by the ANA properly. The effort of the ANA is mainly focusing on providing an adequate infrastructure and regulating well depletion, favouring the agro-exporters, but failing to support the small and medium sized farmers. Another aspect that contributes to the growing gap is the implementation of a maximum irrigation quantity of 150-300 mm of water and drip irrigation. This is a good implementation from an environmental perspective but it has far reaching consequences from a social perspective. The dripping techniques required for more sustainable asparagus production with (only) 150-300 mm of water are not affordable for all farmers which leads to the exclusion of the poorest. Consequently, a major part of the small and medium sized farmers can either cultivate asparagus illegally or stop cultivation completely. The agro-exporters have an even larger advantage over the small and medium sized farmers since they can adapt to the new rules or can avoid the regulation policies. What is good about this scenario is that the industry will keep running, but still illegal extraction from wells could enhance an unsustainable water use. The demand is still higher than the recharge of the aquifer.
Scenario 3: Better position of stakeholders, but no environmental
awareness
The ANA set up more regulation policies as a result of more capital and thus power generated by ProInversion. Hence, the regional and local authorities (AAA & ALA) assigned more responsibility to address illegal water activities for all small to medium sized farmers to address the inequalities within the system: the interests of the agro-exporters are no longer in favor of the small to medium sized farmers. In line with equalising the social networks, more ties are being created between small to medium-sized farmers and the large scale agro-exporters, partly by a more on the front regional authority who actively connects the different stakeholders. In these relations more information is being shared on the irrigation techniques and repairing of wells. In this manner, more small farmers are able to reach the aquifers, and thus compensate partly the removal of illegal wells. Besides, the maximum yield is being pursued, thus both agro-exporters and small to medium sized farmers (with dripping techniques) will use irrigation of 750 mm, because they are not willing to give up the tiniest amount of yield. Furthermore, there will be no installation of plastic mulch, and in combination with the irrigation quantities, this will result in evaporation and will enhance faster aquifer depletion. This threatens the availability of water for all stakeholders in the Ica-valley and will result therefore in new social issues.
Scenario 4: Business as usual
The regulating bodies (ANA, AAA & ALA) do not come up with sustainable strategies. Illegal wells runned by the agro-exporters are increasing and illegal wells from small to medium sized farmers are shut down. Furthermore due to the lack of knowledge or lack of capital, small to medium sized farmers still use the same quantity of irrigation, border irrigation and are unable to use mulch. Agro-exporters, that are not willing to sacrifice any yield and still have the most power, do not change in their water use behaviour. Moreover, no mulch is used, because this is not beneficial in terms of yield. Consequently water extraction from wells will continue to rise and the gap between stakeholders will become larger.
5. Conclusion
This research was achieved in order to generate the most sustainable strategy to address the water balance in the Ica-valley, regarding asparagus cultivation. This most sustainable strategy is achieved by constructing different, possible scenarios, which gave multiple insights in the consequences of integrating the social and environmental findings. As is elaborated in the results, the most water efficient way of irrigation is using drip irrigation techniques, combined with plastic mulch and an additional application of 150 to 300 mm of water. Besides, as the maldistribution of power is the root cause of the social unsustainable situation, the power should me more equally divided amongst all stakeholders. As the most power is for the large-scale farmers, it would be helpful if they were eager to effectively adapt sustainability strategies. However, their main objective is to generate greater profit, thus the ANA should create more power and responsibility to address illegal activities both for small scale, medium scale and large scale farmers, so that the water management is collectively addressed. In this manner, within the first constructed scenario, ‘Government intervention and Good irrigation practises’, the retained results are best incorporated: with the increased economic capital generated by ProInversion, more regulation (by ANA), monitoring (by ALA/AAA) and cooperation/education (by AAA/ALA/agro-exporters) can be organised within the valley. With strict regulation the efficient irrigation techniques and quantities are applied and distributed among all farmers; with education and cooperation the knowledge is shared amongst all stakeholders and with effective monitoring all the farmers will be approached equally.
6. Discussion & future recommendations
A general point of discussion arises from the fact that this research is purely theoretical in the sense that we did not really implement the strategy in the Ica region and collect empirical data on how the strategy changed the water-balance, nor the social interrelations between the stakes. What also comes forward as a point of discussion is the outcome. Even though no literature about asparagus in Ica specifically was found, that mulch and drip irrigation is most sustainable and that agro exporters have the most power was to be expected. Therefore the results will not be of great value to farmers or government in the area, but hopefully they will contribute to the push towards sustainability in the Peruvian asparagus industry. What was not to be expected from the results is that irrigation of 750 mm per hectare (Obtained from reliable literature) is more than necessary and can be reduced by more than half, to make the process more sustainable.
More specifically, in the Aquacrop model no mulch was used with the border irrigation scenarios, so that the irrigation water would not be able to penetrate the soil because of the water impermeable mulch. This is, however, only applicable to plastic mulch. When using another, more organic type of mulch, for instance woodchips, the irrigation water would, indeed, be able to pass through. In this manner mulch and border irrigation could be combined. However, there would probably still be more evaporation than using drip irrigation, due to the slower water absorption by the soil. However, this should be further investigated to reach certainty. Secondly, the effects of the proposed plastic mulch on the environments is not included, while plastic is generally not seen as sustainable. Further research could investigate the feasibility of other types of mulch.
Another point of discussion is related to the salinity. It would be more interesting to ran the Aquacrop model for a longer period than a year, since salinization is a slow process (Cannon & Wentz, 2015). With regards to the irrigation practises, it is important to stress that there are still improvements of the irrigation schedule possible. The used schedule wat the input for every irrigation amount, and the time between each irrigation application could have been optimized, to reach a more realistic schedule. Furthermore, the use of the river water might be unsustainable, as it is discussed that the amount of river water is in decline because of climate change(Hepworth, Postigo & Delgado, 2010). Also we took only the case study of the Villarcur aquifer in consideration. It would be possible that other aquifers could have different circumstances. For future research it is interesting to see the possibilities of genetically modified asparagus, which manage to use less water or other beneficial characteristics.
In this research a limited amount of stakeholders are explicitly discussed. However, it would probably create more insights to incorporate all the stakeholders. Also involving more upstream areas and their communities could create more insights. It would be interesting to investigate the options of including other regions and their lakes/oasis/rivers to address the water scarcity. However it is important to note that this will have influences on the, in this research described social sustainability, as more communities and discourses will be involved. Besides, a considerable amount of information and articles found were in Spanish, which, due to a language barrier, made it sometimes difficult to understand as the information was translated by internet based translation sites.
Lastly, as this is an interdisciplinary project, more strength would be created when incorporating more disciplines. More in-depth could be created by including a business analyst, which could analyse the opportunities of enhancing more economic capital by ProInversion and in turn their investments which could provide capital for all the involved stakeholders.
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8. Appendix
A. Tables Table A1Scenario Nr. Irrigation quantity (mm/per crop cycle) Type of irrigation Surface wetted (%) Salinity (dS/m) Mulches (synthetic plastic mulch) 1 750 Drip 10 0,4 Yes 2 750 Drip 10 0,4 No 3 750 Drip 10 0 No 4 500 Drip 10 0 No 5 300 Drip 10 0 No 6 150 Drip 10 0 No
7 750 Drip 10 0 Yes 8 500 Drip 10 0 Yes 9 300 Drip 10 0 Yes 10 150 Drip 10 0 Yes 11 750 border 100 0,4 No 12 750 border 100 0 No 13 500 border 100 0 No 14 300 border 100 0 No 15 150 border 100 0 No 16 100 Drip 10 0 No 17 100 Drip 10 0 Yes
The 17 different scenarios imported in Aquacrop Table A2
Output parameter
Description
Yield (ton/ha) The yield increase/decrease defines the productivity. Water
productivity (kg/m3)
Water productivity is the amount of kg yield that is produced per m3 water that is evapo-transpired and explains the optimal water usage compared to the yield.
Drainage (mm) The drainage is the amount of mm water that percolates towards the groundwater and is added into aquifers.
Canopy cover Canopy cover (CC) gives an overall view of the canopy over time compared to the reference/potential CCpot (max. of CC under optimal conditions).
Evaporation (mm)
Evaporation is the quantity of mm water transpired from the soils surface.
Biomass ratio (%)
Biomass ratio defines the percentage of actual produced biomass compared to the potential biomass.
Salinity (ton/ha) Salinity is the amount of ton per ha that is stored into the soil after one plant lifecycle
B. Aquacrop outcomes
1 first outcome
Met opmerkingen [1]: The explanation of aquacrop is very nice! One thing to worry about is style and grammar, please by attention to this in the last version.
More importantly, until now there is no good reason given why to do all this. This might also be because context information up to this point is minimal.
I think you can circumvent this a little by first explaining about the social network analysis, but context and case-related info is also a bit thin in that part
What I would like to read is a problem statement out of which aquacrop follows (as it seems to be your only method in your environ. analysis. You do not want to convey the you did your aquacrop for the sake of it. For this perhaps you can improve the first paragraph, before input parameters.
3 Third outcome
5 Fifth outcome
7 Seventh outcome
9 Ninth outcome
11 Eleventh outcome
13 thirteenth outcome
15 Fifteenth outcome
