The Sierra Nevada de Santa Marta, a UNESCO-declared Biosphere Reserve, is an isolated mountain complex encompassing approximately 17,000 km², set apart from the Andes chain that runs through Colombia. The Sierra Nevada has the world’s highest coastal peak (5,775 m above sea level) just 42 kilometres from the Caribbean coast. The Sierra Nevada is the source of 36 basins, making it the major regional ‘water factory’ supplying 1.5 million inhabitants as well as vast farming areas in the surrounding plains used mainly for the cultivation of banana and oil palm. The main problems to be solved in these basins are: i) Declining availability of water for irrigation, ii) Declining availability and quality of water for human consumption, iii) Increasing salinization of ground water and soils, iv) Increasing incidence of floods.

This is a feasibility study on the adoption of more efficient irrigation techniques by oil palm farmers in the Sevilla basin (713 km²), one of the key basins in the Sierra Nevada. The general objective is to identify the local environment at basin scale, the limiting factors and suitable field interventions in oil palm areas to improve the water use. A preparation and implementation phase was developed including an initial baseline assessment of the basin on climate, water availability, drought hazard, soil characteristics, land use, and topography. The agronomy (e.g. cultivars) and current field practices (e.g. nutrient management and irrigation practices) of the oil palm areas were characterized, and the crop water requirements determined. In addition, costs and benefits associated to the implementation of efficient irrigation technologies such as fertigation and water harvesting were assessed. Potential locations, risks and opportunities for water harvesting were evaluated with the idea to store water in the wet season to be able to use the resource in an efficient way in the dry season. A range of GIS and satellite-based datasets (e.g. CHIRPS, MODIS-ET, MODIS-NDVI, HiHydroSoil) were used to evaluate the environmental conditions, and local data and information was provided by local partners Cenipalma and Solidaridad to generate a comprehensive assessment at basin and field scale. The expectation is that fertigation and water harvesting techniques can be adopted in the Sevilla basin, but also in other basins in the Sierra Nevada de Santa Marta to reduce the environmental impact of oil palm production.

In Angola, more and better-quality data is required to improve crop suitability assessments over large extensions of arable land to ensure sustainable food and income security. For example, environmental data on soil texture, soil water storage capacity, vegetation growth, terrain slopes, rainfall and air temperature are key to develop reliable crop suitability assessments. These datasets are available from state-of-the-art satellite-based products and machine learning observations (de Boer, 2016; Funk et al., 2015; Hengl et al., 2014, 2017). The benefit of these data products is that data can be obtained for any province, municipality, or farm in Angola. On top of that, data can be shown in maps to easily visualize spatial variation and identify the most suitable location and area to grow desired crops. Land-crop suitability maps are obtained by calculating a weighted average of the environmental variables that influence crop growth (e.g. rainfall, air temperature, soil water storage capacity), providing an integrated and complete assessment on where to plant. Also, potential crop yields are determined for desired cropping seasons using the FAO AquaCrop model to provide more information about potential income.

Irrigated agriculture in Angola has been developed in commercial farms using mainly central pivot and drip irrigation systems. The installation of new irrigation systems is foreseen in large extensions of land over 5000 hectares. Irrigated agriculture results in higher crop yields and allows higher incomes to farmers. However, commercial farms must invest in high energy supply to operate irrigation systems with water pumping stations. The challenge for irrigation system operators is to know exactly when and how much to irrigate during the cropping season. If better information about irrigation volumes and intervals are provided a significal reduction in energy costs could be achieved. The objective is to predict irrigation demand volumes during the cropping season and provide a user-friendly decision tool to irrigation operators. To achieve this, weather forecasts, remote sensing, and the SPHY model will be used.

The scope of the project work is as follows:

  • Train selected NCBA Clusa PROMAC staff on drone operation, imagery processing software, and crop monitoring;
  • Provide technical assistance to trained NCBA Clusa staff on drone operation, imagery processing, and interpretation of crop monitoring data;
  • Present technical reports on crop development and land productivity (i.e. crop yield) at the end of the rainy and dry season

The trainings and technical assistance for the NCBA Clusa staff are provided in collaboration with project partners HiView (The Netherlands) and ThirdEye Limitada (Central Mozambique). Technical staff of the NCBA Clusa are trained in using the Flying Sensors (drones) in making flights, processing and interpreting the vegetation status camera images. This camera makes use of the Near-Infrared wavelength to detect stressed conditions in the vegetation. Maps of the vegetation status are used in the field (with an app) to determine the causes of the stressed conditions: water shortage, nutrient shortage, pests or diseases, etc. This information provides the NCBA Clusa technical staff and extension workers with relevant spatial information to assist their work in providing tailored information to local farmers.

At the end of the growing season the flying sensor images are compiled to report on the crop development. The imagery in combination with a crop growth simulation model is used to calculate the crop yield and determine the magnitude of impact the conservation agriculture interventions have in contrast with traditional agricultural practices.

In irrigated agriculture options to save water tend to focus on improved irrigation techniques such as drip and sprinkler irrigation. These irrigation techniques are promoted as legitimate means of increasing water efficiency and “saving water” for other uses (such as domestic use and the environment). However, a growing body of evidence, including a key report by FAO (Perry and Steduto, 2017) shows that in most cases, water “savings” at field scale translate into an increase in water consumption at system and basin scale. Yet despite the growing and irrefutable body of evidence, false “water savings” technologies continue to be promoted, subsidized and implemented as a solution to water scarcity in agriculture.

The goal is to stop false “water savings” technologies to be promoted, subsidized and implemented. To achieve this, it is important to quantify the hydrologic impacts of any new investment or policy in the water sector. Normally, irrigation engineers and planners are trained to look at field scale efficiencies or irrigation system efficiencies at the most. Also, many of the tools used by irrigation engineers are field scale oriented (e.g. FAO AquaCrop model). The serious consequences of these actions are to worsen water scarcity, increase vulnerability to drought, and threaten food security.

There is an urgent need to develop simple and pragmatic tools that can evaluate the impact of field scale crop-water interventions at larger scales (e.g. irrigation systems and basins). Although basin scale hydrological models exist, many of these are either overly complex and unable to be used by practitioners, or not specifically designed for the upscaling from field interventions to basin scale impacts. Moreover, achieving results from the widely-used FAO models such as AquaCrop into a basin-wide impact model is time-consuming, complex and expensive. Therefore, FutureWater is developing a simple but robust tool to enhance usability and reach, transparency, transferability in data input and output. The tool is based on proven concepts of water productivity, water accounting and the appropriate water terminology, as promoted by FAO globally (FAO, 2013). Hence, the water use is separated in consumptive use, non-consumptive use, and change in storage (see Figure).

Separation of water use according to the FAO terminology.

A complete training package is developed which includes a training manual and an inventory of possible field level interventions. The training manual includes the following aspects: 1) introduce and present the real water savings tool, 2) Describe the theory underlying the tool and demonstrating some typical applications, 3) Learn how-to prepare the data required for the tool for your own area of interest, 4) Learn when real water savings occur at system and basin scale with field interventions.

Methodology

  • Development of adaptation benefit-cost framework: The framework was developed in a manner to make it possible to isolate development- and climate-related benefits and costs of individual projects and to assess the sensitivity of adaptation benefits and costs to the uncertainty inherent in regional climate change scenarios.
  • Development of analytical tools and procedures: The project developed general procedures and specific analytical tools for consistently measuring the costs and benefits of adaptation projects in the agriculture sector in Africa. These procedures and tools allow multi- and by-lateral development institutions to evaluate the benefits and costs specifically related to climate adaptation “add-ons” to sustainable development projects.
  • Application of analytical tools and procedures: The project applied these procedures and analytical tools to estimate the benefits and costs of a well-defined adaptation project in the agricultural sector, particularly on the predominant crop in The Gambia: millet.
  • Water-crop model:
    A detailed water-crop model has been setup and applied for a reference period and for future projected climates. Adaptation strategies have been defined and explored with the model developed and an economic analysis have been applied on the results.

Overview of The Gambia. Landsat composite from 1990.

The major steps taken were:

  • collection of base data and information
  • extraction of IPCC projections for The Gambia
  • downscaling of these projections to the local conditions for The Gambia
  • setup of a crop-water model
  • evaluation of the impact of climate change on yields
  • definition of adaptation strategies
  • evaluation of the impact of these adaptation strategies
  • evaluation of the economics of these adaptation strategies

Result and conclusions

For the development and application of the adaptation benefit-cost framework data from two GCMs were used while concentrating on the most common grain crop in The Gambia: millet. The most relevant adaptation strategies were selected: crop variety improvements, fertilizer applications and irrigation. However, the modeling framework as it is setup can be easily applied to other GCMs, SRES scenarios, crops, soils, or adaptation strategies.

From the analysis it is clear that the impact of climate change on millet yields depends highly on the GCM selected. The HADCM3 projections indicate a much drier future, while the ECHAM4 ones indicate somewhat more rainfall in the future. Considering the “no-regret” principle, we decided to explore the adaptation strategies for the HADCM3 projections only.

Model mean anomaly for A2 Maximum Temperature °C.

Emphasize was put on the annual variation, and more specifically on the successive years of low yields. Introduction of irrigation appears to be the most successful adaptation strategy, yields will increase and, moreover, year-to-year variation decreases substantially.

Variation in annual precipitation over the entire country (Based on: CRU dataset).

A rough estimate of the benefits in terms of gross return was carried out by multiplying the yield by the price of millet (about $ 0.15 kg-1). For the irrigation adaptation strategy this means that the gross return per hectare will increase from $170 to $235. As mentioned before, the reduction in year-to-year variation by the adaptation strategies will be even more important and should be analyzed in detail.

Finally, the most promising adaptations has to be implemented and successive studies should look into whether these adaptation strategies can be adopted through market forces, whether the government should impose these by subsidizes or tax regulations, or whether bi-lateral aid should focus on this in an effort to minimize risks of food shortages.

For smallholder farming systems, there is a huge potential to increase water productivity by improved (irrigated) water management, better access to inputs and agronomical knowledge and improved access to markets. An assessment of the opportunities to boost the water productivity of the various agricultural production systems in Mozambique is a fundamental precondition for informed planning and decision-making processes concerning these issues. Methodologies need to be employed that will result in an overall water productivity increase, by implementing tailored service delivery approaches, modulated into technological packages that can be easily adopted by Mozambican smallholder farmers. This will not only improve the agricultural (water) productivity and food security for the country on a macro level but will also empower and increase the livelihood of Mozambican smallholder farmers on a micro level through climate resilient production methods.

This pilot project aims at identifying, validating and implementing a full set of complementary Technological Packages (TP) in the Zambezi Valley, that can contribute to improve the overall performance of the smallholders’ farming business by increasing their productivity, that will be monitored at different scales (from field to basin). The TPs will cover a combination of improvement on water, irrigation, and agronomical management practices strengthened by improved input and market access. The goal is to design TPs that are tailored to the local context and bring the current family sector a step further in closing the currently existing yield gap. A road map will be developed to scale up the implementation of those TPs that are sustainable on the long run, and extract concrete guidance for monitoring effectiveness of interventions, supporting Dutch aid policy and national agricultural policy. The partnership consisting of Resilience BV, HUB, and FutureWater gives a broad spectrum of expertise and knowledge, giving the basis for an integrated approach in achieving improvements of water productivity.

The main role of FutureWater is monitoring water productivity in target areas using an innovative approach of Flying Sensors, a water productivity simulation model, and field observations. The flying sensors provide regular observations of the target areas, thereby giving insight in the crop conditions and stresses occurring. This information is used both for monitoring the water productivity of the selected fields and determining areas of high or low water productivity. Information on the spatial variation of water productivity can assist with the selection of technical packages to introduce and implement in the field. Flying sensors provide high resolution imagery, which is suitable for distinguishing the different fields and management practices existent in smallholder farming.

In May 2020, FutureWater launched an online portal where all flying sensor imagery from Mozambique, taken as part of the APSAN-Vale project, can be found: futurewater.eu/apsanvaleportal

There is so far no accepted general methodology for assessing the significance of climate risks relative to other risks to water resources projects that the World Bank Group supports and invests in. The Independent Evaluation Group (IEG) in its 2012 report entitled “”Adapting to Climate Change: Assessing the World Bank Group Experience””, found that “climate models have been more useful for setting context than for informing investment and policy choices” and “they often have relatively low value-added for many of the applications described” and that “although hydropower has a long tradition of dealing with climate variability, the Bank Group lacks guidance on appropriate methods for incorporating climate change considerations into project design and appraisal.”

The book “”Confronting Climate Uncertainty in Water Resources Planning and Project Design: The Decision Tree Framework”” by Casey Brown and Patrick Ray was published in 2015. Since then, the Decision Tree Framework (DTF) has been applied to Bank projects facing diverse situations in six pilots covering hydropower, water supply, and irrigation with funding from the Water Partnership Program (WPP). This effort is continuing in two additional pilots with financing from the Korea Green Growth Trust Fund (KGGTF) targeting the resilience component of water security of flood protection and irrigation in the Nzoia River basin in Kenya and the application of the Hydropower Sector Climate Resilience Guidelines (which in turn are based on the DTF) to the Kabeli-A hydroelectric project in Nepal.

Together with partners, FutureWater applies the following bottom-up methodology DTF to the Nzoia irrigation project in Kenya and the Nepal’s Kabeli-A run-of-river hydroelectric project study. FutureWater´s main tasks are assessing risks using crop modeling and water allocation modeling of the Nzoia case study, and hydrological modeling of the high-mountain region in Nepal.

The Mashhad city is the second largest city in Iran. The economic growth in the Mashhad city is strongly threatened by water shortages and unregulated groundwater extraction. The situation is critical, and the government is considering drastic infrastructural measures such as desalination and water supply from the Sea of Oman (Ministerie van Landbouw, 2018). Hence, finding cost-effective alternatives to reduce groundwater consumption in the Mashhad basin (Figure 1) is of regional interest.

The SMART-WADI project (SMART Water Decisions for Iran), carried out by a consortium of FutureWater, IHE-Delft, and local partner EWERI, focuses on farmers who irrigate their crops with groundwater. The aim is to provide up-to-date information and advice on water productivity, irrigation and farm management. The project combines the latest satellite technology for the quantification of water consumption and productivity, with high resolution flying sensor (drone) images to monitor the crop growth.

Figure 1. Mashhad basin in Iran.

Using this information in a crop model can determine the potential for improving agricultural practices and reduce groundwater consumption. This way, a higher crop yield (food production) and higher water productivity can be obtained (Figure 2). Eventually farmers receive this information in combination with recommendations regarding irrigation planning via an online portal or mobile app.

SMART-WADI is now in the phase of a feasibility project, in which the market context and technical aspects are tested. This is supported by the Partners for Water Program of RVO.nl, with co-funding from the executive project partners. Based on the first signals and the experiences of FutureWater and IHE-Delft in similar projects, it is estimated that this information service has great potential to be scaled up to other areas in Iran.

FutureWater is developing and testing a framework to predict crop yield and water productivity based on crop growth monitoring using flying sensors and remote sensing. Thanks to this innovation, farmers can timely plan field management practices (e.g. irrigation application) enhancing water productivity and reducing groundwater consumption.

Figure 2. Conceptual framework of SMART-WADI.

Nowadays, projects that invest in sustainable water management and agriculture require evidence that the targeted measures to boost water productivity are effective. Water productivity monitoring therefore becomes increasingly important. Water productivity requires data on yields and water consumption (evapotranspiration). Yield data are often difficult to obtain from farmers, especially in areas with many smallholders. Evapotranspiration is even more difficult to assess in the field. Remote sensing-based and model-based monitoring of water productivity has a large potential, also to identify yield gaps and assess the local feasible effectiveness of measures.

The objective of this pilot study was to achieve plot-level maps of water productivity and yield to test a methodology to assess the performance of different farmers in order to provide them with recommendations to improve water productivity. More specifically, this pilot study combined high-resolution imagery from Flying Sensors (FS) with a crop water productivity model to assess yield and water productivity for several plots with maize in Mozambique. Canopy cover was derived from the imagery and linked with the crop model simulations to obtain water productivity maps covering the entire growth cycle. The methodology is also used for the monitoring of crop performance during the growth season and can be used to forecast yield by the end of the season.

This feasibility study demonstrated that there is an opportunity to further develop a service that monitors water productivity based on FS-imagery and crop modelling. Service costs outweigh the additional revenues obtained by farmers. The experimental development has demonstrated that the service is technically feasible and can provide the tangible outputs needed. To bring the proposed service to a higher level of maturity, it is recommended to focus future development activities on (i) Testing for different locations and crops, (ii) Further enhancing link between FS-based imagery and crop modelling, and (iii) Involving end-users and testing within a project where WP-measures are implemented.

Background

A key factor in enabling an increase and efficiency in food production is providing farmers with relevant information. Such information is needed as farmers have limited resources (seed, water, fertilizer, pesticides, human power) and are always in doubt in which location and when they should supply these resources. Interesting is that especially smallholders, with their limited resources, are in need of this kind of information. Spatial information from flying sensors (drones) can be used for this. Flying sensors offer also the opportunity to obtain information outside the visible range and can therefore detect information hidden for the human eye (Third Eye). Nowadays, low-cost sensors in the infra-red spectrum can detect crop stress about two weeks before the human eye can see this.

The ThirdEye project supports farmers in Mozambique and Kenya by setting up a network of flying sensors operators. These operators are equipped with flying sensors and tools to analyse the obtained imagery. Our innovation is a major transformation in farmers’ decision making regarding the application of limited resources such as water, seeds, fertilizer and labor. Instead of relying on common-sense management, farmers are now able to take decisions based on facts, resulting in an increase in water productivity. The flying sensor information helps farmers to see when and where they should apply their limited resources. We are convinced that this innovation is a real game-changing comparable with the introduction of mobile phones that empowered farmers with instantaneous information regarding markets and market prices. With information from flying sensors they can also manage their inputs to maximize yields, and simultaneously reduce unnecessary waste of resources. In summary, the missing information on markets has been solved by the mobile phone introduction, the flying sensors close the missing link to agronomic information on where to do what and when.

Flying sensors

Thanks to our innovation, farmers’ demand for key agricultural information will be satisfied by means of an extension service based on flying sensor (drone) information. The deployment of flying sensors is unique in its ability to provide farmers with real-time, high-resolution, and on-demand information. We provide essential agricultural information:

  • At an ultra-high spatial resolution (NDVI)
  • With unprecedented flexibility in location and timing
  • Based on wavelengths not observable by the human eye
  • With a country-specific business oriented approach.

To this end, we use low-cost high-resolution flying sensors (drones) in a development context to ensure that farmers will get information at their specific level of understanding, and simultaneously develop a network of service providers in Mozambique and Kenya.

A flying sensor is a combination of a flying platform and camera. Reliable flying sensors are on the market in a wide-range of categories each with its specific characteristics. Based on the consortium’s experiences over the last years low-cost flying sensors have been identified that are excellent equipped for our innovation. Typically, a flying sensor flies at a height of 100 meter and overlapping images are taken about every 5 seconds. This results in individual images covering about 50 x 50 meter and an overlap of 5 images for each point on earth. So, in order to cover 100 ha 500 images are taken during a flight.

The use of Flying Sensor is unique and no comparative techniques exist that provide farmers with real-time high-resolution information. The use of satellites to provide farmers with spatial information has been promoted but has three main limitations: they have fixed overpass times, the spatial resolution is low, and the presence of clouds halters the information. It is unlikely that, within the coming decades, progress in satellites will be real competitors of flying sensors. Another category of comparable techniques to provide farmers with information is the use of ground sensors. Typical examples of these sensors are soil moisture devices, soil sampling and laboratory analysis, crop sampling and laboratory analysis. However, all those sensor techniques have the common limitation that information is only local point representative, while the main question farmers have is regarding to spatial differences. Moreover, these ground sensors are in all cases too expensive to be used by small-scale farmers.

Our flying sensors have cameras which can measure the reflection of near-infrared light, as well as visible red light. These two parameters are combined with a formula, giving the Normalized Difference Vegetation Index (NDVI). This information is delivered at a resolution of 2×2 cm in the infra-red spectrum. Infra-red is not visible to the human eye, but provides information on the status of the crop about two weeks earlier than what can be seen by the red-green-blue spectrum that is visible to the human eye. NDVI is the most important ratio vegetation index and says something about the photosynthesis activity of the vegetation. Moreover, NDVI is an indicator for the amount of leaf mass, and therefore, ultimately biomass. In general, open fields have a NDVI value of around 0.2 and healthy vegetation of around 0.8. NDVI values give an indication of crop stress. This can be caused by a lack of water, lack of fertilizer, pests or abundancy of weeds.

This Flying Sensor is equipped with infrared sensors that detect crop stress about two weeks before the naked eye can observe this.
This Flying Sensor is equipped with infrared sensors that detect crop stress about two weeks before the naked eye can observe this.

NDVI technology

When light falls on a leaf, reflection occurs. The amount of reflection of green light (0.54 µm) is very high, making plants green to the human eye. Healthy vegetation does not reflect much red light (0.7 µm), since it is absorbed by chlorophyll abundant in leaves. In the near-infrared spectrum (0,8 µm) the amount of reflection increases rapidly to 80% of the incoming light. This increase is caused by the transition of air between cell kernels. This is characteristic for healthy vegetation.

Damaged plant material does not show this increase in reflected near-infrared light. Moreover, the reflection of red light is much higher than in healthy plant material. By measuring the reflection in these spectra, damaged plant material can be distinguished from healthy plant material (Schans et al., 2011).

With our NDVI technology damaged plant material can be distinguished from healthy plant material.

Progress

From 2014 to 2017, FutureWater has been granted support from the Securing Water for Food program, funded by USAID, Sida and the Dutch Government of Foreign Affairs, for piloting the use of flying sensors to support farmers in Mozambique with their decision making in farm and crop management. In Mozambique, we have transferred our technical skills to local ThirdEye operators over the past 3 years. We currently have 6 active local operators providing service to more than 3,500 farmers over more than 1,600 ha. These operators are able to support over 400 small-scale farmers, by collecting information and sharing it with farmers on weekly basis. Based on the information, farmers take decisions on where to do what in terms of irrigation, fertilizer application and pesticides, helping them improve their water productivity. Furthermore, they now have the capacity to deal with technical issues and are very skilled in providing advice to farmers. As a result, the farmer’s water productivity was increased by 55%, meaning less water is used to achieve the same crop yield as without ThirdEye services. ThirdEye has evolved since 2014 from a start-up to becoming the leading company in Mozambique in the field of mapping and monitoring services for farmers based on aerial images, which will continue to expand its activities over the coming years.

Since last year, the ThirdEye service is also implemented in Kenya as part of the Smart Water for Agriculture program implemented by SNV. Last month the first round of training was given to 5 operators, who will be serving at least 2,000 smallholder farmers the coming months. Training consists of flying sensor use, technical skills, safety and protocols, imagery processing and consultancy. After this, the operators will start working regularly in the regions of Meru and Nakuru. Here they will go the farmer’s fields, conduct flying sensors flights, process the images and give advice on improving their agricultural practices. Next to the service for smallholder farmers, ThirdEye delivers various services to medium and big sized farmers.

Training new operators in the field.
Training new operators in the field.

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