Introduction

In order to assess how our project could improve sustainability in agriculture, we first needed to get a good understanding of what makes an agrosystem sustainable and what sustainability challenges exist in agriculture today. Therefore, on top of a lot of individual research, we also reached out to various stakeholders, including agroecologists, farmers, ethicists, and lawyers, for further insight.

Water availability, phytopathology and fertilizer use were at the core of our sustainability research as RhyzUp aims to improve crops' ability to retain water, resist drought, combat pathogens, and absorb nutrients.

Using the knowledge gained from our research and interviews, we evaluated how our project relates to the 17 United Nations (UN) Sustainable Development Goals (SDGs).

TARGET 2.4: 1) DROUGHT AND FOOD PRODUCTION

Feeding an ever-growing population is a huge challenge. The Food and Agriculture Organization of the United Nations (FAO) estimates that 5% of annual agricultural GDP is lost to natural disasters every year2, with drought being the natural disaster that causes the most agricultural production loss. Particularly in low to middle income countries, drought as a single cause has led to 34% of crop and livestock production loss between 2008 and 2018.3 Therefore, we focused not only on drought as an issue in Switzerland but also tried to investigate how water availability is an issue globally. In the following, we address how drought, precipitation, and water management affect agriculture today and in the future.

TARGET 2.4: 1.1) DROUGHT IN SWITZERLAND

Although Switzerland is known for its abundant water resources, drought is predicted to become an increasing issue for local farmers. By 2035, precipitation is expected to increase in winter but decrease by about 15% in summer. In 2020, 4.7% of agricultural land in Switzerland was irrigated, but this figure is predicted by Agroscope to rise in future years.4

In dry years, water availability can become a pressing issue for Swiss farmers. In 2018, many Swiss farmers struggled with dry periods during the summer. This led to the Swiss Farmers' Association formulating a package of measures, calling for stability in fodder supply in the event of extreme drought.5 This shows that while drought and water availability may not be Switzerland's biggest problem at the moment, it will certainly become more important in the future.

In our interview with Rahel Emmenegger, deputy managing director of the Swiss Grain Producers Association (SGPV), we learned that not all regions of Switzerland are equally prone to drought. According to her, especially the axis from the Lake Geneva area to the canton of Schaffhausen is at greater risk of drought than other areas of Switzerland. Also, certain alpine valleys, such as the Rhone Valley and the Engadine, are at higher risk of water scarcity. This shows that water availability is often a very local issue and that drought mitigation measures need to be implemented where they are most important.

Using symbiotic rhizobacteria, as we do, is very cheap and easy to implement. There are several potential implementations of RhyzUp that make use of existing technology, which means that using our rhizobacteria would be a very accessible way for farmers to combat water scarcity. This knowledge can be found in the chapter Entrepreneurship and Implementation of the Human Practices Folder.

In addition, Rahel Emmenegger informed us that not all crops are equally sensitive to drought. This means that in Switzerland, crops that grow mainly during summer are more affected by water shortages than crops that are sown in fall. Specifically, drought is a threat to crops such as potatoes, many field-grown vegetables, grasses for fodder cultivation, and maize.

TARGET 2.4: 1.2) DROUGHT IN ETHIOPIA

Because Ethiopian agriculture is highly dependent on rainfall, and reduced rainfall drastically impacts food security, there have been several instances of drought causing humanitarian crises in the past years. Parts of southern Ethiopia are currently facing one of the most severe droughts on record, leading to huge deficiencies in crop and livestock production.6

Our interview with Dr. Mosisa Wakjira, a Wageningen-based researcher focusing on agrometeorology and its implications for sustainable agriculture in Ethiopia, provided valuable information for understanding Ethiopia's agrometeorology like the impact of rainfall variability on Ethiopian agriculture. Understanding water availability in an East African country helped us broaden our picture of drought and its impact on the local farming systems.

For the full interviews, take a look at the Interviews subpage of Human Practices.

Approximately 95% of Ethiopia's arable land is rain-fed. This means that crop production is almost entirely dependent on rainfall without the possibility of irrigation. Ethiopia can be broadly divided into two areas in terms of rainfall seasonality: unimodal rainfall regimes, characterized by one season of rainfall, and bimodal regimes, where rainfall usually occurs in two periods per year.

The implications for agriculture are different in the two regions. In unimodal rainfall regimes, where more water is usually available at once, the temporal distribution of rainfall and the growing season are critical for crop yield, while the amount of water available is not the main issue. In bimodal regimes, however, water availability can become a severe problem during the growing season, as total rainfall is split into two periods, leaving less water available for agriculture during both seasons. Crop yields in these regions therefore depend on the amount of water available and are highly sensitive to changes in rainfall. Farmers in bimodal regimes need to find ways to prevent water loss and improve water storage.7

TARGET 2.4: 1.3) GLOBAL PERSPECTIVES OF DROUGHT

Worldwide, about 20% of all cropland is irrigated, while 80% is rainfed.

Irrigated agriculture accounts for about 40% of global crop production, while rainfed agriculture accounts for 60%. Per unit area, irrigated agriculture is much more productive than rainfed agriculture.8

Currently, much of the world's cropland is shifting from rainfed to irrigated,which has important implications for watersheds, water quality, and quantity9. 70% of freshwater is already used for agriculture, and the increasing popularity of irrigated agriculture is one of the main drivers of global freshwater demand. This poses a sustainability issue, as global freshwater resources are limited. For example, the freshwater consumption of Saudi-Arabia was more than nine times higher than their annual renewable freshwater resources in 2020.10

Rainfed agriculture, which currently accounts for more than half of all crop production, also faces new challenges due to climate change. As average temperatures rise, more water evaporates and is lost. Also, rainfed agriculture is way more vulnerable to drought than irrigated agriculture.

In addition, the seasonality of rainfall is projected to become more uncertain, which will also make farming more difficult and poses risks to crop yields. The increase in rainfall fluctuations was identified as a problem for agriculture by several of the stakeholders we spoke with: Rahel Emmenegger, Vivienne Oggier, and Fritz Meier. According to these experts, uncertainty about rainfall is a problem for farmers. In very wet years, fungal pathogens are more prevalent and lead to high yield losses, while in very dry years, agro-systems per se are less productive, and overfertilization may be an issue.

TARGET 2.4: 2) PLANT PATHOGENS AND FOOD PRODUCTION

Every year, 20 to 40% of crops are lost to pests.12 Protecting crops from pests is critical to food security and poverty alleviation, which in turn ensures healthy lives.13

The ecology of many plant pathogens is highly dynamic. Climate change is causing changes in the distribution, reproduction, and severity of some of the pests that cause the most economic damage to agriculture.14 In addition, increased global trade may result in the more rapid spread of plant pathogens from one geographic area to another.15

The above arguments demonstrate the need for plant resistance to pathogens. Not only is resistance to specific pathogens critical for agriculture, but also a plant’s general pathogen resistance.

TARGET 2.4: 3) IMPROVING FERTILIZATION

Food production relies heavily on providing crops with adequate nutrients. As a result, fertilizer use has increased dramatically in recent decades, with major impacts on ecosystems worldwide.

If agricultural systems are to remain productive in the future without causing too much damage to ecosystems, fertilization must become more efficient.17

The situation in Switzerland is no different. Because of the surplus of nitrogen and phosphorus in Swiss agriculture, the Swiss Federal Council decided on April 13, 2022, to reduce nitrogen and phosphorus by 2030.18 According to Rahel Emmenegger, this reduction path for fertilizers has strong implications for farmers. Because many farmers are forced to use less fertilizer, the protein content of crops is lower than before, which in turn negatively affects the selling prices of these crops. Fertilization efficiency is crucial to ensure that nutrients actually end up in the crops being produced.

TARGET 3.2: NEONATAL MORTALITY AND FOOD SECURITY

Of the 200 countries or territories identified by the UN, 54 have not yet reached the under-five mortality target.19 The goal is to reduce under-five mortality to less than 25 deaths per 1,000 live births.22

UNICEF attributes about half of all under-five deaths to malnutrition. Without sufficient food and essential nutrients, children are at greater risk of infection, and infections are more severe than in well-nourished children.23

TARGET 3.9: REDUCTION OF PESTICIDES

According to the European Environment Agency, exposure to certain chemical pesticides has been linked not only to cancer and chronic heart, respiratory and neurological diseases but also to acute symptoms such as headaches, irritation, vomiting and skin rashes.24^,25 In recent decades, environmental organizations and public health officials have been increasingly emphasizing the need to reduce the use of chemical pesticides in agriculture.

Pesticides are a topic of ogoing debate, and with yields and incomes at risk, farmers may not be able to consider alternatives to chemical pesticides, depending on the crops they grow and the methods they use. With this in mind, we as a team were convinced that developing alternatives to chemical pesticides is critical not only for biodiversity and the conservation of endangered species but also for human health and well-being. To better understand the options available to farmers in Switzerland today, we spoke with Fritz Meier, a local crop grower; Vivienne Oggier, who works as a crop protection and pest control advisor at the Agricultural Center in Saint Gall, Switzerland; and Rahel Emmenegger, who represents cereal, oilseed and protein crop growers. For the full interviews go see the subpage “Interviews” of Human Practices.

Fritz Meier said that in extreme cases, chemical pesticides are the only way to ensure the survival of his crops and prevent huge yield losses. At the same time, according to Vivienne Oggier, many pesticides are now subject to stricter regulations than they were a few years ago. In the field where Vivienne Oggier's partner grows beans, this has led to significant yield losses because the standard insecticide for seed treatment was banned and no alternatives are left.

Rahel Emmenegger noted that while there are many feasible efforts to reduce pesticides in cereals, this is hardly possible for some oilseeds, such as rapeseed. Her association, the Swiss Grain Producers Association, has supported research to find alternatives for rapeseed, but the results have not been very promising so far.

TARGET 6.3: WATER POLLUTION OF FERTILIZERS AND PESTICIDES

The most significant contributors to water pollution from agriculture are excess nutrients that accumulate in water bodies and the buildup of nitrates and pesticides in rivers, lakes, and groundwater, which not only disrupt aquatic ecosystems but also pose health risks to humans and animals.28 For example, exposure to high levels of nitrates in drinking water can lead to methemoglobinemia, commonly known as "blue baby syndrome," which can be fatal for infants.29

The impact of fertilizer runoff on ecosystems is described in “Target 15.1: Reducing Eutrophication”.

Additionally, runoff water from agriculture often contains soluble fertilizers which can lead to contamination of lakes, streams and groundwater. Human exposure to pesticides through dermal contact or ingestion increases the risk of immunosuppression, hormone disruption, reduced intelligence, reproductive distortion and cancer.30 It is therefore of great interest to reduce the amount of pesticides used in agriculture.

TARGET 6.4: IMPROVING WATER-USE EFFICIENCY

In our interviews, we explored different types of irrigation systems used in Switzerland. At Gebrüder Meier, we discovered an innovative approach to the production of "hydro salads" using a closed irrigation system in their greenhouses, where the water is enriched with all the necessary nutrients. Residual water and nutrients are simply collected and used in the next cycle.

Even though greenhouse systems try to maximize water use efficiency, water is still a cost factor, according to Fritz Meier. Using RhyzUp to further improve water-use efficiency in greenhouses would, therefore, be beneficial for both sustainability and crop growers' bottom lines.

While Gebrüder Meier's greenhouses are a model example, and greenhouses have become increasingly important and efficient in recent decades31, agriculture still faces many challenges in implementing efficient and sustainable irrigation systems, and it is unrealistic for agriculture to completely switch to closed irrigation systems, as greenhouses represent only a small portion of the global land used for crop production. In addition, growing crops in greenhouses comes with higher capital costs and energy consumption that many growers worldwide could not afford.

Fortunately, our engineered Pseudomonas strain could also be used in the open field. According to Dr. Mosisa Wakjira, open field agriculture loses a lot of water to runoff. It could therefore greatly benefit from the improved water retention provided by our project.

TARGET 13.1: ADAPTING TO CLIMATE CHANGE

The 13th goal of sustainable development is not only about reducing greenhouse gas emissions as the main cause of climate change but also about adapting to the consequences of climate change. This is stated in target 13.1: “Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries”.34

In addition, the strain of Pseudomonas we have developed promises to clear out troublesome root pathogens and improve overall plant resistance to pathogens. As the world's climate changes, so will the distribution of pathogens.16 It is difficult to predict which pathogens will be able to spread to which parts of the world, and each pest must be considered separately. In general, however, climate change will lead to longer growing seasons, which will allow many pathogens to increase their time to reproduce and spread. Pathogenic organisms that evolved in temperate and cold regions are generally exposed to temperatures cooler than their physiological optima. Rising global temperatures could, therefore, lead to increased pathogen pressure, particularly at higher latitudes.35

TARGET 15.1: REDUCING EUTROPHICATION

Target 15.1 is worded as follows: “By 2020, ensure the conservation, restoration and sustainable use of terrestrial and inland freshwater ecosystems and their services, in particular forests, wetlands, mountains and drylands, in line with obligations under international agreements.”37 Although the target year has passed, much more can be done to protect inland freshwater ecosystems.

Runoff of phosphate and nitrogen compounds from agricultural fertilizers increases eutrophication.38 Eutrophication is a process in which plants and algae grow excessively on surface waters. It reduces sunlight penetration to the lower layers of water, which reduces photosynthesis in submerged aquatic plants, leads to lower levels of dissolved oxygen, which kills aquatic organisms such as fish that serve as food for many other organisms and leads to the production of toxins by cyanobacteria. Eutrophication is often associated with a loss of biodiversity.39

TARGET 15.5: MAINTAINING INSECT BIODIVERSITY

Target 15.5 is on the protection of biodiversity and natural habitats and is worded as follows: “Take urgent and significant action to reduce the degradation of natural habitats, halt the loss of biodiversity and, by 2020, protect and prevent the extinction of threatened species.”37

Pesticide use has been identified as one of the main drivers of insect biodiversity loss, although it is now more regulated than ever in many parts of the world.40 Non-target organisms such as bees have been found to be exposed to pesticides in the EU, even in protected habitats.41 As noted in chapter "Target 3.9: Reduction of Pesticides", three of the stakeholders we spoke to emphasized that, in some cases, the use of pesticides is crucial to ensure crop yields. This shows that there is still a need for good alternatives to chemical pesticides.

TARGET 15.8: PREVENTING OUR BACTERIA FROM BECOMING INVASIVE

While designing our project, it was important to us to ensure that our engineered bacteria would not invade environments where we did not want them. To do this, we included a xylose sensing mechanism to initiate biofilm production, a kill switch when the bacteria would not be in the presence of xylose as a root exudate, and modes of implementation, such as adding the bacteria to microgranular fertilizers that would limit the spatial distribution of our bacteria.

Thinking about the ecological consequences of the use of your projects is crucial. Reto Flückiger of Andermatt Biocontrol, a company that sells products based on rhizobacteria, told us that in order to be approved for commercial use, the bacteria must be endemic to the region of application.