Science and Management Symposium
Lessons Learned from Extreme Drought and Tree Mortality in the Sierra Nevada:
How Can Past Events Inform our Approach Forward?

Thanks to all who attended our Drought and Tree Mortality Symposium on July 25th in Sacramento. With nearly 170 attendees across a wide range of sectors, the event provided a meaningful opportunity for reflection, analysis, and consideration of next steps. We appreciate you prioritizing your participation and hope that you found value in the sessions.

For those interested in viewing the material presented, the agenda and presenters’ slide decks are now available here as PDFs to download.

It was with great regret that we learned of the passing of Dr. Kelly Redmond, deputy director of the Western Regional Climate Center and professor at the Desert Research Institute. Dr. Redmond passed away on November 4, 2016, after a long battle with cancer. He was a highly respected climatologist, a veteran science communicator, and an enthusiastic mentor to young climate scientists.

Ever since 1989, when NOAA created its six Regional Climate Centers, Dr. Redmond held the position of Regional Climatologist for the Western US. The NOAA RCCs were at the vanguard of federal attention to climate variability and change, and they helped pave the way for climate programs at other agencies, including the USDA Climate Hubs. Dr. Redmond provided advice and guidance to the California Climate Hub (and our sister Hub, the Southwest Climate Hub based in Las Cruces, NM) ever since our inception in 2014.

As Regional Climatologist, Dr. Redmond not only worked to improve data collection and analysis for the West’s complicated and variable climate, he strove to inspire and inform popular interest in these topics. He often gave public lectures (for example, on climate change and Western water at the Aspen Global Change Institute’s 2003 annual lecture) and media interviews (for example, to Capital Public Radio about ENSO influences on 2015 summer thunderstorms). His devotion to public service and outreach in no way diminished his prolific career as a research scientist.

At the 2015 US Drought Monitor Forum in Reno, NV, Dr. Redmond discussed the challenge of seasonal forecasts: land users want short-term predictions, but current models are unreliable at that time scale. “We need to consider the ‘angle of repose‘, Dr. Redmond said. “Some problems have a steep angle of repose: it doesn’t take long to stack the building blocks up tall and reach your answer. Other problems have a shallow angle of repose: you need to amass a huge base of additional knowledge before you can even begin to make headway. Which type of problem is this? The climate system is chaotic at monthly time scales, so I would argue that it is the latter – but it is still worth pursuing. We just need to be in it for the long haul.”

Thank you, Dr. Redmond, for your sustained effort on climate puzzles large and small, and for eloquently bringing these topics into the public view. Your Climate Hub colleagues will miss your insights and encouragement.

A memorial service for Kelly Redmond will be held at 2 PM on Friday, January 13, at Truckee Meadows Community College in Reno. You can RSVP here.

The 2016 Natural Areas Conference (Davis, CA, 18-21 October) was a big success, with over 300 presenters on a wide variety of topics related to climate change, conservation, and natural and working landscapes.The California Climate Hub was proud to be a sponsor and organizer of this conference.

Though NAC is a national conference, this year’s meeting highlighted California ecosystems: for example, hydrological restoration of Sierra meadows; monitoring endangered fauna in California’s Central Valley; and managing cattle grazing to benefit rare plants in California grasslands.

A particular focus was the difficult question of how to manage California’s water-stressed forests under the assumption that future climate change will bring more droughts like the current one. In the organized session “Forests in the Oven,” researchers presented preliminary data on the effectiveness of techniques such as stand thinning and prescribed fire to reduce drought-related tree mortality. This is an active area of research for Climate Hub affiliates Jim Thorne and Mark Schwartz.

The final day of the Natural Areas Conference also included field trips near Davis. For example, Khara Strum from Audubon California led participants on a tour of Yolo Bypass, a local success story in integrating conservation lands, intensive agriculture, and urban development.

If you missed the conference, you can still catch up by taking a look at the abstract book and videos of the two plenary sessions – freely available to all.

On August 17-18, 2016, the North American Symposium on Climate Adaptation brought together practitioners from across the continent to discuss adaptation in a variety of systems from agriculture to resource-poor urban neighborhoods to coastal infrastructure. The USDA Climate Hubs were well represented, with members of the Northeast Hub (Dan Dostie, Lynn Knight), California Hub (Amber Kerr), and Northern Forests Hub (Todd Ontl) attending.

All Climate Hubs shared some of the successes and challenges they’ve had in trying to connect their stakeholders with adaptation advice. Todd Ontl described the user-driven, iterative framework behind their Forest Adaptation Workbook and presented data on forest managers’ adaptation activities. Dan Dostie emphasized the need to find “win-win-win” approaches that maximize climate benefits, ecosystem services, and economic profitability. Lynn Knight highlighted the role that Climate Hubs play in educating other USDA staff about climate change. And Amber Kerr (also presenting on behalf of Isabel Pares of the Caribbean Hub) described the issues involved in working with diverse farmers cultivating a variety of annual and perennial crops in an area with complex microclimates – a challenge that Puerto Rico and California both share.

The discussion at the “Climate Change and Agriculture” session of the Symposium reflected the fact that farmers’ major climate risks vary quite a bit according to where in North America they are located – for example, in California, the biggest concern is generally drought and limited water supply, whereas in the Northeast, excess or heavy precipitation is a major concern. However, at the moment, the Northeast is having its worst drought in many years. Stay tuned for more drought-related collaborations between the California Hub, the Northeast Hub, and other Hubs nationwide.

The symposium proceedings will be published in 2017 in the book “Climate Change Adaptation in North America: Experiences, Case Studies and Best Practices,” part of Springer’s Climate Change Management Series.

For those of us who are not agricultural experts, the different categories used to describe crops can be bewildering. Field crops. Row crops. Horticultural crops. Specialty crops. Vegetable crops. Cash crops. What are all these designations? Which ones are mutually exclusive, and which ones overlap?

In fact, it can be confusing for the experts, too. Some of these terms have ambiguous or disputed definitions. Some are used differently in the US versus in other parts of the world. And some are based on cultural preferences rather than on agronomic or botanical distinctions.

This post lays out some of the most common ways that the USDA groups and describes crops. Although it is not definitive, we hope that it will be a useful brief reference for anyone new to this topic.

Annual crops vs. perennial crops
This is a fairly straightforward distinction: annual crops are those that must be replanted every year (such as corn and sunflowers), whereas perennial crops are those with a multi-year lifespan (such as almonds and oranges). Most vegetables, grains, and oilseeds are annuals, whereas most fruits are perennials. Some crops that are really perennials (such as strawberries) or biennials (such as carrots and cabbage) are, in practice, treated as annuals and replanted every year to maximize yields.

Field crops vs. specialty crops
This distinction is unique to the USDA: specialty crops are defined as fruits, nuts, and vegetables (including floriculture and nursery plants), while field crops are everything else (grains, dry legumes, oilseeds, fiber crops, and hay). This can lead to some unexpected dichotomies: for example, green beans are a specialty crop, while dried beans are a field crop. Walnuts are a specialty crop, while peanuts are a field crop (because they’re dry legumes). Sunflowers grown for oil are a field crop, while sunflowers grown for the floral industry are a specialty crop. And, although you probably think of potatoes as vegetables, the USDA categorizes all potatoes (including sweet potatoes) as field crops.

Agronomic crops vs. horticultural crops
This is a less common terminology for making the same distinction as field crops vs. specialty crops, above. Agronomic crops are generally non-perishable crops such as grains, dry beans, oilseeds, and fiber, while horticultural crops are fruits and vegetables, mainly grown for their “contribution to the flavour and interest of food and for the supply of minor but essential nutrients.”

Row crops
Some non-technical dictionaries simply define “row crop” as “a crop planted in rows,” but almost all commercial crops – from delicate baby lettuces to massive olive trees – are grown in rows. In practice, the term “row crop” usually refers to annual crops that are mechanically harvested on a large scale. This makes it roughly synonymous with field crops / agronomic crops, but not exactly: “row crop” can include some mechanically harvested annual specialty crops (such as tomatoes and onions). Note that perennial orchard crops such as grapes and almonds are never referred to as row crops, even when grown in rows and mechanically harvested.

Fruit vs. vegetable crops
Botanically, a fruit is the mature reproductive part of a plant (containing seeds), while a vegetable can be any other part of the plant, such as leaves, stems, roots, or tubers. However, USDA uses colloquial definitions: tomatoes, eggplants, peppers, and squash (even melons!) are all classified as vegetables by USDA’s National Agricultural Statistics Service (NASS), even though they are botanically fruits. Nearly all “vegetables” are annuals and nearly all “fruit” are perennials, with the notable exceptions of strawberries (an annual fruit) and asparagus and artichokes (perennial vegetables).

Cash crops and commodity crops
A cash crop is simply a crop that is sold for cash, and a commodity crop is a cash crop that is traded on a large scale (usually globally). In the realm of international agricultural development, “cash crop” is often contrasted with “staple crop” or “subsistence crop” – i.e., a crop that a farmer grows for her own family’s sustenance. However, in the United States where nearly all farm output is sold rather than directly consumed by the farm family, you’re more likely to hear “cash crop” contrasted with “cover crop,” i.e., a crop that is primarily grown to improve the soil, not to be sold for a profit.

One final fact: Trees as crops
Trees and forests managed for timber are not considered crops by USDA (though felled orchards may produce salable wood as a byproduct). The only timber trees that appear in the NASS agricultural statistics are fresh Christmas trees, which are classified as a nursery crop. (In 2007, the most recent year for which NASS data are available, sales of cut Christmas trees totaled more than $210 million – that makes them a bigger player than many other specialty crops, such as asparagus or kiwifruit.)

Are there any other crop classifications or definitions you’d like clarified? Please let us know and we can discuss them in a future post!

Over the past few decades, California farmers have steadily improved their water use efficiency (or “crop per drop”). However, the current drought and future climate change provide an imperative for even greater efficiency. Russell Ranch, UC Davis’ sustainable agriculture research facility, helps inform this effort via long-term irrigation field trials. Here are some highlights from this year’s Russell Ranch Field Day (June 8, 2016), themed “Farm Water Management in Times of Scarcity.”

Several Russell Ranch trials focus on subsurface drip irrigation. Surface drip irrigation has taken off in California since 1980, but subsurface drip irrigation (SDI) remains relatively uncommon due to its greater upfront expense and more complicated operation. However, SDI has promise for reducing evaporation and minimizing soil disturbance in crops such as tomatoes, a high-value commodity grown in water-limited areas.

Amelie Gaudin showcased her lab’s Russell Ranch experiment on organic tomato systems, examining effects of SDI on soil health. Her preliminary results show that SDI (compared to furrow irrigation) has so far maintained high tomato yields while reducing weed pressure, but it also seems to reduce soil aggregate size, which may pose a concern for long-term C storage.

Dan Putnam and others described their long-term study of SDI in alfalfa at Russell Ranch. Currently, SDI is used in less than 2% of alfalfa acreage, but this trial suggests that SDI may deserve wider adoption: not only does it increase water use efficiency, it can even increase total alfalfa yields due to more uniform soil wetting and better weed control. However, alfalfa SDI systems face a big problem from a small pest: pocket gophers love to make their homes in alfalfa fields, and they readily chew through the underground plastic tubing. (Field day attendees witnessed several puddles caused by gopher damage.)

A key step in irrigating efficiently is knowing how much water the crop needs to keep up with evapotranspiration (ET). Many California farmers schedule irrigation according to real-time ET data from their nearest CIMIS weather station. Data from a farmer’s own field can be considerably more accurate, but on-farm ET measurements are too costly for most farmers. A new technology called surface renewal (developed by the Hub’s own Andrew McElrone and others) may help change this. These lower-cost ET sensors, now commercialized by Tule Technologies, are on display at the Russell Ranch alfalfa trial.

These are only a few examples of the research presented at the 2016 Russell Ranch field day. Other researchers discussed the water-energy nexus in the context of groundwater well pumps; remote sensing of crop water stress; and creating soil maps to inform groundwater recharge. The Climate Hub aims to keep up with these innovations and help get the word out to farmers who are dealing with climate variability and change on the ground.

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On average, water pumping accounts for 70% of the agricultural energy use in California. This number only grows during drought years. As electricity prices rise and drought drives farmers to depend more heavily on deeper wells and falling groundwater tables, the out-of-pocket energy costs of managing an agricultural operation grow. However, a majority of farmers still use electric pumps to draw their water as opposed to diesel engines—an 85% to 13% split, according to the 2013 USDA Farm and Ranch Irrigation Survey. Thankfully, while diesel engines do offer some unique conveniences, there remain a significant number of financial and environmental benefits to the current preference for electric-powered pumps.

Off-road diesel-powered pumps are more common in areas that are separated from the grid, where extending power lines to connect to the grid are often more expensive in the short run than the alternative–though annual savings from switching to an electric pump can offset these costs over time. Nevertheless, drawing power from fossil fuels like natural gas or diesel offers its own freedom from time-of-day electricity rates. Around one-third of water use on California farms happens during expensive peak hours, and while groundwater can be pumped during off-peak hours and kept in storage tanks until needed, the same can’t be said for booster pumps which need to be fired to pressurize water for irrigation. Booster pumps in California use nearly two-thirds the same amount of energy that is expended by well pumps, so diesel offers some benefits by allowing farmers to evade the costly power use of booster pumps during peak hours.

However, electric pumps have their own edge. Since there is no internal combustion involved in the pumping process, electric pumps need maintenance far less often than fossil fuel pumps, and last longer. Electric pumps also offer flip-the-switch convenience, and unlike engines, are not subject to costs from emissions regulations by air pollution districts. The environmental benefits of electric pumps are also significant, as electric pumps produce no local air pollutants, create less noise, and have lower greenhouse gas emissions over their lifetimes. This is in strict contrast to diesel engines, which are significant sources of nitrogen oxides and fine particulate matter that pollute the San Joaquin and Sacramento Valleys.

Electric pumps also provide flexibility to forward-thinking farmers, who can more easily transition their pumps to greener energy sources, including solar power, wind power, or power from burning methane released from cattle manure and crop residues.

Additionally, as the state transitions more of its power production to cleaner, renewable sources, the greenhouse gas footprint of electricity will fall even further.

This is not to say electric pumps are free of climate impacts. The grid is still powered primarily through fossil fuels. However, the efficiency at which the fuel is burned in a power plant vastly outweighs the efficiency of a small combustion engine, which means that a given unit of fossil fuels will generate more energy at a power plant than in an engine. Furthermore, electric pumps on the market usually draw more water per unit of expended energy than a diesel pump, as shown below.

Ultimately, the higher efficiency of electric pumps and the significant cost of diesel will usually make electric pumps the wiser option for most California farmers, despite fluctuations in electricity rates. A growing number of options are also becoming available to farmers to save water and energy, which may help mitigate possible growth in electricity prices. Several major utilities offer adjusted rates for agricultural pump users, including PG&E and Southern California Edison, and numerous programs by local, state, and federal agencies can save farmers money by helping them transition to more efficient irrigation systems and lower energy use.

• PG&E rate program
• SoCal Edison rate program
• List of assistive programs, grants, etc. offered by the private and public sectors