California Ag Network

Tag: Sacramento Valley

  • California Rice Fields Provide Vital Habitat for Snakes, Birds and Fish

    From ducks and cranes to giant garter snakes and salmon, flooded rice fields in California’s Central Valley offer important — often vital — habitat to many wildlife species. Yet uncertainties around crop markets, water and climate can prompt some growers to fallow rice fields or change their management practices.

    Will today’s rice acreage under current practices be enough to meet key species’ needs? If not, how much rice is needed? Where should it be planted? And what management practices offer the greatest benefit for species of concern?

    Scientists from the University of California, Davis, and Point Blue Conservation Science address these questions in a new report, “A Conservation Footprint for California Rice,” written for the California Rice Commission.

    “This was a highly interdisciplinary effort that I don’t think has been attempted at this scale for California rice or perhaps any other California agricultural crop working with wildlife,” said report co-lead John Eadie, a UC Davis professor emeritus in the Department of Wildlife, Fish and Conservation Biology who coordinated the 173-page effort among 13 authors. “I think this report provides the baseline for future work to come.”

    Core needs

    The authors reviewed the core needs of key species living among the region’s rice fields. These include giant garter snakes, wintering ducks, wintering and breeding shorebirds, black terns, sandhill cranes and native fish. They developed a mapping framework of the species’ habitat, as well as an estimate of the rice acreage, management practices and priority locations for rice that would most greatly benefit each wildlife group.

    Over the past decade, rice acreage has ranged from 250,000 to 540,000 acres in California. The report found that approximately 470,000 to 500,000 acres defines the desired conservation footprint of rice for the most species of concern. The needs for different species include:

    • 30,000 acres for native fish
    • 43,000 acres for sandhill cranes
    • 80,000 acres for giant garter snakes
    • 373,500 acres of winter-flooded rice and flooded fallow rice fields for non-breeding shorebirds
    • 473,000 acres of planted rice to restore populations of black terns and help support breeding shore birds
    • 500,000 acres for wintering ducks

    Winter flooding critical

    The authors emphasize that rice acreage alone — even as much as 500,000 acres — will not sustain these species unless water is available during the winter and during critical periods in the fall and spring. Winter flooding of the rice fields is especially critical for many of these species.

    Historically, seasonal wetlands shaped the Central Valley’s ecology and biodiversity. Beginning in the mid-1800s, these lands were largely drained for agriculture, flood control and development.

    “In the absence of natural wetlands, rice has become essential surrogate habitat for an incredible diversity of California wildlife,” said report co-editor Daniel Karp, a UC Davis professor in the Department of Wildlife, Fish and Conservation Biology. “In the face of climate-induced droughts and escalating water prices, providing rice farmers with the support needed to continue flooding their fields in winter is absolutely essential to safeguard this incredible conservation success story.”

    Priority locations and management solutions

    For nearly all wildlife groups, the Colusa and Sutter basins rank as the highest priority locations for rice habitat, given their proximity to wetlands and wildlife refuges. The Yolo Basin, Consumnes-Mokelumne Rivers region, and parts of the Delta are especially important for shorebirds and sandhill cranes. The Yolo and Sutter bypasses also represent critical areas for fish in flooded rice fields.

    The conservation value of these areas, however, largely depends upon how they’re managed. In addition to winter flooding and water availability, spatial location, managing vegetation, irrigation canals and post-harvest rice straw are just some of the considerations when managing rice for wildlife. The report outlines several strategies for each group.

    “This kind of interdisciplinary work is challenging but so important to effective conservation,” said report co-author Kristen Dybala, a principal ecologist at Point Blue Conservation Science. “When we work together, we can identify opportunities for the same acres to contribute to multiple goals at once.”

    The value of rice

    In addition to providing habitat for wildlife, rice production creates about $1 billion of added economic value and up to 7,500 jobs for California’s Sacramento Valley.

    “For decades now, our growers have seen firsthand how much their rice fields are used by wildlife all throughout the year,” said Tim Johnson, president and CEO of the California Rice Commission. “This Rice Footprint report by the University of California, Davis, details how these same fields that grow America’s sushi rice serve as the economic driver for our small communities and are also vital to our ecosystem in helping waterfowl, shorebirds, reptiles and fish thrive.”

    The report was funded primarily by the California Rice Commission through a grant to the UC Davis Center for Watershed Sciences and to Point Blue Conservation Science.

    Additional authors include Francisco Bellido-Leiva, Lee Burrows, Sean Fogenburg, Andrew Rypel and Brian Todd of the UC Davis Department of Wildlife, Fish and Conservation Biology; Robert Walsh of Point Blue Conservation Science; Bruce Linquist of UC Davis Plant Sciences; and Daniel Sumner and Jessica Xu from UC Davis Agricultural and Resource Economics. — By Kat Kerlin, UC Davis

  • Digging Deep: Exploring the Diversity of Soils in the Sacramento Valley

    Sacramento, Calif., (November 7, 2017) – Not more than three months on the job and Konrad Mathesius is hard at work bringing farmers together to discuss the unique challenges that Sacramento Valley farmers face. As the new UCCE agronomy advisor for Sacramento, Solano and Yolo counties, his role is designed specifically to help growers with their crop issues – pests, disease and fertility – but with a strong background in soil science, Mathesius hopes to shed light on the diversity of soils in the region and the unique management considerations that each necessitates.

    Participants gather around the first soil pit of the field tour, as Toby O’Geen provides a brief natural history of the land.

    In hopes of highlighting this diversity of soils and encouraging growers to dig a little deeper to better inform their management practices, Konrad enlisted the help of UCCE soil resource specialist Toby O’Geen to lead a field tour of three major soils in the southern Sacramento Valley. The event included three pit stops on two Yolo County farms and brought out a diversity of participants from USDA Natural Resources Conservation Service agents, to resource conservationists, to farmers and crop advisors.

    Kicking things off at Rominger Brother’s Ranch — a diversified family farm in Winters that grows everything from wine grapes to processing tomatoes to rice, wheat, corn, onions, alfalfa and hay — O’Geen took the audience on a journey back in time, describing the rich natural history of the former floodplain that has given rise to the rich, productive soils that support California agriculture today. After introducing himself as a pedologist, or a scientist who studies the nature and properties of soil, he went on to introduce the five soil forming factors and their role in molding initial (1) parent material (i.e. rocks), under the influence of (2) climate, (3) topography and (4) organisms and over a given period of (5) time into soils.

    Yolo County farmers and UC Cooperative Extension specialist Toby O’Geen, right,peer deep into the processes that formed the land just beneath their feet.

    Proving that soil scientists take the term “pit stop” literally, Mathesius shifted the conversation to a 1.5-meter deep hole in the ground, dug out the day before with a back hoe. Step by step, he walked participants through the process of analyzing a soil pit – cleaning the face, identifying horizons or individual layers and using the senses to assess soil properties and determine function. As he struck the face of the pit with a rock hammer, an audible difference was detected between the surface layers and the subsurface.

    Working backwards from the sound, he explained that the subsurface was significantly harder, which he attributed to a finer texture and ultimately identified as a clay pan, a restrictive layer that prevents roots from penetrating deeply and has the capacity to waterlog soils, due to poor drainage. O’Geen offered some tangible advice as to how to manage these soils, quipping that a deep rip would be no better than cutting butter with a knife (eventually it all just settles back into place) while likening a slip plow to a giant shank that just inverts the soil, mixing things to about a depth of 6 feet and permanently eliminating the problem.

    UCCE agronomy advisor Konrad Mathesius, left, talks soil texture and water-holding capacity.

    From there, Mathesius segued into a hands-on exercise to determine the soil texture, or percent distribution of various size particles, allowing participants to work on their pottery skills making balls and ribbons with the clay-rich soils.  Discussing the many functions that soil texture controls, led the conversation down a rabbit-hole around water holding capacity and how to calculate the range of plant available water for your soil.

    With the demos out of the way, they voyaged to the next pre-dug pit, bringing participants face to face with the harsh reality of soil heterogeneity. Just 300 feet away and it was as if we had ventured into another environment altogether, yet these soils formed in the same place, under the same climate and similar vegetation, but in a completely different time with slightly different starting material.

    By changing just a couple of the ingredients in the special sauce of soil formation the results are completely different featuring a clay dominant surface soil and entirely different water management challenges. And these aren’t just any clays, but a special class that swell and shrink as they wet and dry, oftentimes shearing roots under the pressure and creating a hospitable environment for disease to thrive.  O’Geen suggested trying to keep them in the sweet spot where they are consistently moist, but not wet, and never allowed to dry out. Unfortunately, there is no precise measurement to that formula, “you just have to be almost like an artist. It’s a lot of feel to it and the numbers sometimes just don’t work out. It just comes with years of experience. Its one of those native intelligence things that you just have to feel your way through,” he noted.

    Up close and personal with a soil pit, showing participants how to use basic tools of observation to assess soils!

    Caravanning 20 miles back towards Davis, the tour arrived at the third and final pit, located at Triad Farms, a tomato operation in Dixon. Well-drained, young and fertile, Yolo loam soils are the poster children of agriculture, owing in large part to regular deposits of silts from past flood events. With not many management challenges to speak of, conversation immediately shifted towards an undocumented challenge that farmers on the eastern side of the Sacramento Valley are all too familiar with – the unavailability of potassium, even under intensive fertilization regimes. While the jury is still out on the cause and while it contradicts what soil scientists expect to find in those regions, possible explanations were tossed around and O’Geen used the opportunity to stress the importance of speaking up about things growers or advisors see going on in their area. Turns out the USDA-NRCS is working on updating its inventory of soil surveys, documenting soils across the nation and is currently seeking input on what’s working for growers and where things are differing on the ground.

    Ultimately, in closing, Mathesius called for more engagement between the university, extension and growers. O’Geen reminded everyone that “You can really learn a lot by digging a hole, looking at stuff, and developing theories.  Sometimes you’re wrong, but they’re kind of fun to talk about.”