How California Farmers Are Sustainably Managing Water In The Field

The Golden State is not only home to one of the world’s few Mediterranean climates, but also one of its leading agriculture powerhouses. Its water use - especially for agriculture - is constantly in the spotlight.

Over the last decade in particular, California’s water management and supply have received heightened attention as the state experienced a historic, state-wide drought from 2011 until 2016. Farmers, the government, and the media have brought increased focus to the need for water conservation and water quality preservation across the state.

As California’s latest drought begins to unfold, we thought we’d dive into what makes California’s climate unique, and what farmers are doing to weather these recurring periods sustainably and successfully.

California: Only One Of Five Mediterranean Climate Regions In The World

Many crops, especially permanent crops such as wine grapes, tree nuts, citrus, stone fruits and others grown in California, require very specific climate conditions to be productive. These crops need long, hot and dry summers, followed by cooler, wet winters in which the temperature drops close to but not below freezing. The summertime heat is crucial for budding, flowering and fruit development, while the winters allow trees and vines to go dormant, enabling them to bloom and fruit again the following year.

This combination of weather conditions is commonly referred to as a Mediterranean Climate. Fairly scarce around the world, this climate type can generally only be found along western coasts of continents between 30-40 degrees latitude in the northern and southern hemispheres. Globally, there are five major regions in the world that combine these characteristics: The coasts of the Mediterranean itself, Chile, Southwest Australia, South Africa, and California.

Periodic droughts are a feature of all Mediterranean climates, yet California has perhaps the most pronounced oscillations between wet and dry, as well as the most robust infrastructure and resources to navigate both. The 2016-2017 rainy season was officially the wettest on record and came directly on the heels of one of the most severe multi-year droughts in the state’s history.

That being said, California has always experienced these intense swings between drought and flood, allowing farmers, government and industry players alike to be well prepared. The state is crisscrossed with canals and aqueducts controlled by federal and state governments, which have been in use since the mid-20th century. These sources allow farmers to access surface water largely on-demand. The government is currently in the midst of implementing a landmark new groundwater management law prompted by the 2011-2016 drought, that will ensure the sustainable management of water from its aquifers.

Having discussed a bit about California’s unique climate and history of droughts, let’s explore what tools and technologies farmers are implementing today to conserve water and ensure a sustainable future.

Drip Irrigation and Automated Irrigation Scheduling

Perhaps one of the most effective ways many farmers are saving water is by installing more efficient irrigation systems. California’s farmers have been particularly active at installing micro-drip irrigation in place of less efficient systems such as flood irrigation or center-pivot sprinklers. To deliver irrigation water in extremely precise doses, drip irrigation uses perforated hoses that can either lie on the soil surface or be installed sub-surface. Properly installed, this technology gives farmers unparalleled water savings - up to 80% compared to other methods.

On top of conserving water, drip irrigation is often paired with software that farmers use to automate the scheduling of each irrigation to match the evolving conditions on the farm, as well as the state of maturity of their crops. Crops have fluctuating water demands throughout their growing seasons, as the plants develop leaves, flowers, and fruit; timing the delivery of water to the moments of the plants’ greatest need is essential. Automated scheduling enables farmers to plan for these events proactively, and to ensure that along with conserving water, the water they deliver to the crop is utilized effectively.

Drip irrigation technology has gained popularity across California agriculture given how transformative it is for both each individual growing season, and the long-term maintenance of water supply. Along with making each farm more efficient, it has allowed California’s agriculture industry to expand, enabling the state to produce more crops on more land without compromising its limited water supply.

Water-Saving Soil Management Techniques

Beyond which irrigation system they use, many farmers are also actively conserving water by boosting the health of their soils and reducing erosion. All soils have a specific water holding capacity, or level of moisture the soil can retain and keep available for crop use. Farmers aim to keep their fields close to capacity throughout the growing season to ensure a healthy crop.

This capacity varies based on two major characteristics: soil texture and organic matter content. Soil texture can be defined as the physical makeup of the soil and how well it forms soil “aggregates”. Soils high in clay or silt particles, as well as those with high organic matter content, generally aggregate more effectively given their higher surface area; this allows the soil particles to hold onto the water more effectively. Sandy soils, given their larger particle size, generally hold less water.

Introducing extra organic matter can transform a soil’s water holding capacity. Organic particles’ chemical characteristics give them a unique ability to bond with water particles, and therefore soils high in organic matter will hold water more effectively almost regardless of particle size.

Farmers can do several things to boost these soil characteristics, including using cover crops and fertilizing with compost. Row crop growers can also deploy conservation tillage methods - either tilling less frequently or not tilling at all - to keep residues from past crops in the soil and allow them to decompose naturally. Cover crops can be used with both row and permanent crops, and along with introducing organic matter. Moreover, they also provide the benefit of slowing water runoff from fields, giving the water time to percolate into the soil and thus enabling the farmer to irrigate less.

Deficit Irrigation Strategies

If water supplies are particularly tight during a drought, many farmers maintain substantial yields and turn a profit by diligently developing and following a deficit irrigation strategy. Deficit irrigation simply means controlling how much a field drops below its water holding capacity throughout a growing season, and timing the periods of water deficit such that they do not coincide with the points in a crop’s maturation where its water demands are the highest.

This is extremely common in Mediterranean climates like California’s and is regularly practiced during droughts, often with very positive results. In fact, studies have shown that not only can deficit irrigation planning save water without severely compromising yields, but it can also boost the economic productivity of water.

In California, permanent crop growers have to plan their season around constraints like this; the state’s research community has made specific recommendations for how to approach these scenarios, especially for some of its most popular crops.

Drought-Tolerant Varieties and Rootstocks

Finally, another important option many farmers are taking advantage of in their quest to conserve water is choosing to plant specific varieties that have been bred for resilience to drought. Drought-tolerance is a highly sought-after characteristic for crops, and plant breeders have been intensifying research and development of these varieties for decades. Beyond saving water, planting these tried and tested varieties can give growers peace of mind even in the face of severe water shortages.

There is a wide range of drought-tolerant varieties available commercially for both row and permanent crops. Whereas row crop growers can plan to change varieties each year, permanent crop growers have to absorb a bit more risk in choosing which varieties to plant given the multi-year productive life of their crops. To add some flexibility, research into drought-tolerant permanent crops often focuses on using drought-tolerant rootstock onto which other varieties can be grafted.

Drought Resilience Is An Important Part of Farmland Investing

Farmers have had to navigate intense droughts in California and around the world for centuries. Each farm has its own hydrological reality, which is shaped by its available supplies of water, its inherent physical characteristics, and how water is managed in the field. Successful navigation of periods of drought isn’t about simply using less - it’s about using available supplies with an eye to both the short- and long-term future.

FarmTogether’s approach is to do three key things with respect to drought management: (1) Carefully screen and evaluate properties based on their water resource characteristics, (2) Invest only where we see indications that the farm will perform well and have ample water available, even during a drought, and (3) work with our operators to ensure they have everything they’ll need to accommodate drought conditions in the field.