As one of the world’s most precious resources, water is vital to life on earth in innumerable ways. When it comes to agriculture, water is at the very center of the industry and must be managed mindfully to ensure successful continued production. Join us as we embark on a comprehensive assessment of water management in agriculture, looking at how water has been mismanaged over the years and how we can improve moving forward. While it is clear that not all aspects of water management are in a grower’s control, growers are responsible for educating themselves on best water management practices to optimize the use of this indispensable resource.
As the first user of water resources (about 70-80%), agriculture “needs to radically increase its efficiency to respond to declining resources” (1). As this resource becomes more scarce, the demand grows for adequate drinking water for a growing population and clean water that supports a healthy ecosystem for humans and wildlife alike. While switching to more sustainable practices is a start, every facet of water management in agriculture needs to be looked at to mitigate and ultimately eliminate problems at their very source - before the runoff creates more significant issues that are more difficult to address.
A Growing Problem or a Problem With Growing?
While some of the effects of agriculture on waterways are straightforward, others are not immediately obvious. Of course, as synthetic chemical inputs became more widely used in the 1940s and beyond, it was to be expected that the excess of these harmful pesticides, herbicides, and fungicides would eventually find their way into surrounding waterways. While it is true that biologically healthy soil can act as a filter for contamination, as the soil is depleted of its natural microbiology, the contaminants will begin to leach through more and more. Chemical inputs are not the only problem, and a growing number of farmers are becoming more mindful of their effects, causing them to implement more natural alternative solutions.
However, just because something is labeled as natural does not mean it can be used without consequence. Some natural inputs may still cause an imbalance of nutrients in the soil. For example, inputs that are exceptionally high in nitrogen may still be considered natural - but if that nitrogen is not all taken up by the plant roots, the excess will still run off and leach into surrounding waterways. It has been established that this higher concentration of nitrogen (and other nutrients like phosphorus) can lead to “Eutrophication, [which] promotes algae growth and depletes oxygen in the water [having a] severe impact on aquatic life and water quality.” (2).
Another issue that can occur naturally is excess water salinity. While salts are naturally present in soil and water bodies, if a field is not properly irrigated, this can lead to salt buildup and larger saline deposits in waterways. The result is salinization, which can harm the biodiversity in fresh water, affecting many species of organisms, animals, plants, and algae (3). Additionally, farms that raise livestock can contribute to the pollution of waterways as their waste can be washed into aquifers and bring with it excess nutrients, but also viruses, bacteria, parasites, and traces of any antibiotic treatments that farmers may be using.
While some runoff from these farms goes directly into waterways through heavy rain or excess irrigation, some also make their way into the aquifers that feed into widely used irrigation systems. The problematic components from the runoff are deposited as sediment in the aquifers. They are not being cleared out each time new water is replenished - amplifying the problem for farmers and making it difficult to resolve.
When Water Sources Run Dry
One of the significant problems facing the agriculture industry over the last decade has been increasing drought caused by mostly unpredictable changes in climate. One of the hardest hit areas in the USA is California, which ranks first in all 50 states for agricultural exports due to the generally mild climate and fertile land. The drought problem has gotten so bad that legislation has been passed in California to try to mitigate the problem, with the government introducing the Sustainable Groundwater Management Act in 2014 (4).
While the legislation has been introduced to improve the situation, it poses a challenge for smaller growers in the Central Valley who may be unable to afford to buy land in areas without water regulations. This may contribute to a decline in crop diversity as smaller farms will be forced to only produce their most profitable crops. And, as a catch-22 - less variety in crops can result in increased water contamination due to nutrient imbalances, soil erosion, and less biodiversity.
The consistent drought also means that the water in aquifers is being used up more quickly than it is being replenished. This drives up the costs for water filtration and means that wells continuously need to be dug deeper, posing an issue to the land itself. With no water holding the land up and in place, many parts of California face subsidence when the land continues to sink lower due to the lack of structure underground (4).
The Connection Between Soil and Water
Water quality and soil health are connected, especially in agriculture; you cannot have one without the other. Whatever the soil cannot hold ends up in the water system - and that same water eventually ends up in the soil. Poor soil with too loose of a structure will lead to increased nutrient leaching and erode more quickly into waterways, bringing viruses, bacteria, and pathogens along with it. In contrast, soil with no drainage will lead to concentrated salt and mineral deposits that will harm fields, and the runoff from this soil will also create problems for waterways.
When soil is tilled and disturbed often, the organic matter and microbes will quickly degrade and no longer be able to cycle nutrients. Anything that is applied to the top of the soil will simply be flushed with the next rainfall - so not only is the runoff water highly polluted and toxic, but the farmer’s investment in fertilizer or other inputs is simply being washed away.
A balanced, healthy soil with enough organic matter to be well structured will hold the appropriate amount of water. This water will contribute to nutrients being more available for plant uptake and less likely to be washed away unused.
The Ongoing Search for Solutions
While water management has been a hot topic in agriculture for many years, there has also been headway made toward potential solutions. The growing regenerative movement prioritizes issues such as water management; those following regenerative agriculture principles are seeing promising results in restoring balance to our waterways. By eliminating soil-degrading practices such as tilling, monocropping, and leaving fields fallow, water sources can benefit from the reduction in contamination.
Allowing the soil to regenerate, leaving room for soil organisms to multiply and thrive, increasing the organic matter in the soil, and allowing it to cycle nutrients properly - this helps tremendously with water being retained in the soil where it is needed. When soil can hold that water in the root zone, it continues to provide life for the microbes in the soil, which in turn consume the nutrients and make them available for plant uptake. This means fewer nutrients being washed away with rainfall and irrigation efforts - and healthier plants that keep the cycle moving in the right direction. Natural soil amendments have been proven to help quickly improve the soil's health while other sustainable practices are slowly being implemented.
Aside from optimizing soil health, farmers need to closely monitor their water use and diagnose problems as soon as they are found. Things like rainwater harvesting, water conservation, and investing in drip irrigation throughout their fields are helpful ways that farmers can help to minimize their use of this resource while still ensuring the growth and health of their crops. Farmers can also determine the amount of water a crop needs and apply only what is required (3).
While farmers need to be aware of how they use their resources, they are not the only ones responsible for solving water management issues. Many farmers have been engaging in the same practices for decades and possibly generations - if something is working well for them, asking them to change their methods might be met with resistance and apprehension. Governments and policy-makers must educate farmers on the situation and offer incentives to adopt better practices that can make a difference. Offering training in more sustainable methods and then measuring their performance against those of their fellow growers can encourage farmers to continue implementing the techniques needed to improve water use and management.
As new technologies become available, farmers need to have access to them. With ongoing advancements in water filtration systems, it is essential for farmers to know what is available, at what cost, and how to install and use them (5). Farmers can make the most of their water by reusing it onsite without constantly sourcing more from the depleted aquifers. Even as new technology evolves and becomes available, farmers can also resort to more traditional methods of water management - those that have proven effective over decades of widespread use. Farmers can create strategic areas for water runoff to flow, directing it to their empty fields to return to the ground instead of into waterways. Recycling water from urban areas can also be a better alternative to continuing to deplete wells.
As we look at the various solutions concerning water management in agriculture, it is clear that plenty of options are available. Each farmer can assess their particular situation and find something that works for them that they can implement without disruption to their usual production practices. Continuing to provide training and education to farmers should be the priority of the government and policy-makers. Water is a finite resource that the entire planet must share - and it is in our best interests to use it wisely and continue to improve our management of this most precious resource.