The Nexus between Energy, Food, Land Use, and Water
Application of a Multi-Scale Integrated Approach

The Republic of Mauritius

  • The Nexus Assessment Project was commissioned by the Energy Team of the Climate, Energy and Tenure Division (NRC) of the UN Food and Agriculture Organisation (FAO)

    and sponsored by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ).

Sugarcane plantation in Mauritius; courtesy of Asadbabil.
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Since its independence in 1968, The Republic of Mauritius has developed from an agricultural based to a diversified economy by strongly expanding its financial and tourism sectors. Most of its arable land is planted to sugarcane (78% in 2010) for sugar exports, which provide a mere 4% of the Gross Added Value while draining most of its natural resources (90% of water). At the same time, Mauritius is importing most of the food and energy it consumes.

What are the prospects of using the actual exports of sugar for internal production of biofuels? What options are there for alternative patterns of agricultural production on the islands to become more self-sufficient in food?

Objectives

The objective of this case study was to single out the agricultural sector of Mauritius and analyze the energy, water, food, and monetary flows in relation to the requirement of human activity, power capacity and land use, with a special focus on the pattern of imports and exports. To this purpose, we (i) analyzed the option of using actual sugar exports for internal production of biofuels to produce local energy carriers, thus increasing energy self-sufficiency, and (ii) explored an alternative pattern of agricultural land use on the island to increase local food production, thus increasing food self-sufficiency.

Data for the analysis were obtained from the Ministry of Finance and Economic Development and the Ministry of Agroindustries and Fisheries of the Republic of Mauritius, as well as from FAO. All data refer to 2010 unless stated otherwise.

Diagnostic step

The integrated characterization of the present metabolic pattern of Mauritius is presented in Fig. 6. The upper (7 x 7) matrix characterizes the pattern of consumption. The 7 columns represent, respectively, the three flow elements, food, energy, and water, the three fund elements, human activity, power capacity, and managed land, and monetary flows (gross added value in the various compartments). The rows represent the 5 compartments of society (HH, SG, BM, AG, EM) and exports for the paid work and agricultural sectors. Exports must be considered given that part of the flows consumed and funds employed is used to this end. In biophysical terms the latter is a “use” of flows and production factors to generate products and services that are not consumed in society. Agricultural exports have been separated from those of the rest of the paid work sector to single out the agricultural sector, thus emphasizing its large water consumption and poor added value. The lower (2 x 7) matrix characterizes the pattern of supply. The 7 columns are the same as in the upper matrix and the 2 rows distinguish between local supply of the various flows and funds and those obtained by imports.

In Fig. 7 we illustrate for the food consumption in the household sector how the integrated characterization establishes a relation between a single aggregate number (5.9 PJ of food energy consumed in the household sector) and the fund elements human activity and land-use. Indeed, the aggregate number is defined by two matrices, one based on dietary requirements and one based on primary agricultural products. The former establishes a link to demographic characteristics (note that in this accounting tourists are considered as a small number of “resident-equivalent” in relation to their food requirement) the latter to agronomic variables and geographic characteristics. Thus, in this way, we establish a relation between quantitative data on food flows and: (i) dietary requirements of the population; and (ii) the supply of agricultural products. This makes it possible, in turn, to perform a spatial analysis on the available dataset on food flows in relation to both the requirement side (size of the resident population and its geographic distribution: urban and rural – top right of Fig. 7) and the supply side (size of crop fields and yields of the various agricultural products – bottom left of Fig. 7). This integrated analysis makes it possible to apply the Sudoku effect to the multi-level representation based on vectors and matrices generating more robust scenarios.

Scenario 1: Using the present sugarcane output for local ethanol production

A first scenario is using all of the present sugarcane output for local ethanol production rather than for sugar export. This scenario implies that all of the production factors – the entire area planted to sugarcane (78% of agricultural land) and the power capacity and human labour involved in its production – and the relative input flows (water, energy, and food) presently allocated to the agricultural sector (more specifically, agricultural export) are moved to the energy and mining sector to produce energy carriers for local use. In our accounting system based on matrices, this scenario is implemented by moving the vector of “end uses” that is now in the compartment of “Export Agriculture” in Fig. 6 and sum it to the vector of “end uses” of the energy and mining sector.

Taking into account that the gross supply of biofuels from crops is dramatically reduced by the internal loop of energy carriers in the production process, the net supply of energy carriers to society from the local production of biofuels is only 8 PJ. This contribution will reduce energy imports by only 5%, but claim 90% of the water-use in Mauritius.

Scenario 2: Replacing sugarcane with food crop cultivation to improve food self-sufficiency

Another interesting scenario for Mauritius is shifting the agricultural production from sugarcane monoculture to food and feed crop cultivation to increase the level of food self-sufficiency. The results of this simulation show that this scenario is impossible for two different reasons: (i) shortage of labour (internal constraint); the Sudoku cannot be solved in relation to the fund element human activity; and (ii) shortage of suitable land (external constraint).

Internal constraint: Labour shortage – The labour requirement per hectare for the cultivation of the selected crop mix is much larger that for sugarcane. Therefore, switching to food crops will increase the labour requirement in the agricultural sector. This increase is incongruent with the existing profile of allocation of labour in society. Implementing this scenario would demand a major re-adjustment of the allocation profile of labour over the different economic sectors. The low economic labour productivity in agriculture (ELP = gross added value produced in a sector divided by the hours of human labour in that sector) does not encourage such re-adjustment. In fact, the ELP of agriculture is the lowest of all economic sectors in Mauritius (as in all the other modern economies). Therefore, a re-allocation of the work force in favor of agriculture would lead to a reduction in the overall added value generated in Mauritius.

Alternatively, if we would maintain the labour supply in agriculture at its present level (83 million hour in total) and have all farmers cultivate food crops (rather than sugarcane), only 22,000 hectares of agricultural land could be cultivated (because of labour shortage). That is, only 30% of the agricultural land presently in production. This is a clear example of an internal constraint (shortage of labour) that would prevent making full use of available resources. This situation could be improved by increasing the biophysical labour productivity (output/hour) through use of machinery; however, this will increase the cost of production. This option could be considered if the internal food supply could be sold to tourists and residents at high prices. This would require some marketing strategies to valorize the market value of local products (e.g., traditional delicacies, special local recipes, organic products). Achieving economic viability for the internal production of crops is essential to justify its adoption in the first place.

External constraint: Shortage of suitable land − A large-scale move from existing sugarcane plantations to food crop production for internal consumption is subject to geographic constraints, including soil type, slope, and hydrological characteristics. The traditional crop mix cultivated right now in Mauritius cannot be simply extrapolated to the entire area presently under sugarcane. Using the existing crop characteristics (but obviously other crops and varieties could be introduced) we assess that the existing crop mix can only be expanded on 64.6% of the agricultural area. Maize could perhaps be grown on some of the rest (another 22% of the total), given the demand for this cereal to feed chicken in Mauritius is large, leaving the rest of the area (13.4%) to sugarcane. This new crop mix, with a dramatic reduction of sugarcane, will positively affect water metabolism, reducing the consumption of water of the agricultural sector.

In this second scenario the shift from sugarcane plantations to food cultivation (taking into account internal and external constraints) will not significantly improve the level of food self-sufficiency for Mauritius. The internal coverage of the food requirement will increase from 16% to 33% of the total.