All Issues

Cultivating urban agriculture

Cover: Urban agriculture is growing statewide, as California cities increasingly allow food plants in front yards and under power lines, and bee hives and chicken coops in backyards. To help city dwellers produce food proficiently and safely, UC Cooperative Extension is developing research-based best practices for urban agriculture (page 199). In addition, the California Animal Health and Food Safety laboratory system offers free post-mortems for backyard poultry through the Backyard Flock program (page 203). This diagnostic service enables researchers to collect data on disease trends and can help amateur poultry producers keep their flocks healthy. Photo by Peter Bennett, greenstockphotos.com.

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Special issue: Methyl bromide alternatives

Cover: Growers have long used methyl bromide to essentially sterilize soil, but this fumigant is being phased out due to environmental and health concerns. New research helps identify methyl bromide alternatives to control pathogens, pests and weeds in strawberries (p 139), almonds and stone fruits (p 128), forest nurseries (p 153) and perennial nursery crop stock (p 181), and shows that multi-layer tarps reduce fumigant emissions (p 147). This work is part of the Pacific-Area Wide Integrated Methyl Bromide Alternatives Program, a USDA-funded collaboration of UC and USDA researchers. Shown is a strawberry field in coastal southern California, a region where fumigants are restricted to protect people’s health. Photo by Janet Hudson

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New life for conservation banks: Reforms streamline landmark program

Cover: Conservation banks enable farmers, ranchers and other landowners to receive income for managing their lands to benefit wildlife. The Golden State established the nation’s first such program in 1995, and has pioneered protection of biodiversity and species at risk. However, since 2009 the number of conservation banks approved yearly has declined to zero, partly due to an unwieldy application process. Now a new law (page 85) and further proposed reforms (page 86) promise to streamline the program. Additional conservation banks could restore critical habitat and protect riparian corridors. Shown is the Thomes Creek tributary coming into the Sacramento River, above Chico at River Mile 326. Photo by Geoffrey Fricker

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Hands-on learning: Healthier choices, better lives

Cover: Garden-enhanced nutrition education increases children's fruit and vegetable intakes, helping to address high childhood obesity rates (page 30). Research indicates that long-lasting improvements are achieved through multiple efforts — offering healthy foods on school campuses; teaching nutritional and environmental science in the context of gardening; and involving communities and regional agriculture (see pages 13, 21). Shown are students tending their vertical garden at Downtown Value School in Los Angeles. The school also has a flower and produce garden that goes around the school grounds, a small greenhouse and a worm compost bin. Photo by Peter Bennett/Green Stock Photos.

October-December 2013
Volume 67, Number 4

Peer-reviewed research and review articles

by Sarah Stinson, Asli Mete

Abstract

CDFA-funded necropsy services provide reliable health information to owners of backyard flocks and gather much-needed data.

The California Animal Health and Food Safety laboratories provide free necropsy (postmortem examination) services to owners of backyard poultry through the Backyard Flock program funded by the California Department of Food and Agriculture. We collected and analyzed data on the number of poultry submissions to the program between 2007 and 2012, the lab totals by location and the diseases diagnosed. During those 6 years, submissions increased 383%, with chickens representing 91% of them, and the greatest increases occurred in Santa Clara, Los Angeles and Sonoma counties. The necropsy data showed that the digestive (32.5%) and hemolymphatic (16.9%) systems were the most commonly affected. Marek's disease accounted for 13.3% of diagnoses (492 cases). With the rapid rise in the number of poultry being raised by amateur producers, biosecurity education is essential.

Testing protocol ensures the authenticity of organic fertilizers

by Fungai N.D. Mukome, Timothy A. Doane, Lucas C.R. Silva, Sanjai J. Parikh, William R. Horwath

Abstract

After analyzing 180 fertilizer materials and products labeled as organic, the authors developed a set of metrics that indicate probable adulteration by synthetic nitrogen.

There is a pressing need for methodology to confirm the authenticity of fertilizers labeled “suitable for organic production.” In this study, we developed a testing protocol that can be used by laboratories and regulatory agencies to detect adulteration of organic fertilizers and soil amendments with a synthetic nitrogen source. By conducting an extensive literature review and analysis of 180 commercially available raw materials, organic fertilizers, soil amendments and synthetic fertilizers, we compiled a comprehensive database of quantifiable properties of those materials. We analyzed their ammonium content, C:N ratio and stable nitrogen isotope ratio, and for each metric we set thresholds that flag products with a high probability of adulteration. The protocol can be used to authenticate organic fertilizer products and bring transparency to the industry.

Totally impermeable film (TIF) reduces emissions in perennial crop fumigation

by Suduan Gao, Bradley D. Hanson, Ruijun Qin, Jose Cabrera, James S. Gerik, Dong Wang, Greg T. Browne

Abstract

Three field trials make a case for TIF use in preplant fumigation of perennial crops.

Many perennial nursery fields and replanted orchards and vineyards in California are treated with preplant soil fumigants to control soilborne pests. In annual crops, such as strawberry, covering fumigated fields with totally impermeable film (TIF) has shown promise in controlling emissions and improving fumigant distribution in soil. The objective of this research was to optimize the use of TIF for perennial crops via three field trials. TIF reduced peak emission flux and cumulative emissions by > 90% relative to polyethylene tarp during a 2-week covering period. After the TIF was cut, emissions were greatly reduced compared to when tarps were cut after 6 days. TIF maintained higher fumigant concentrations under tarp and in the soil than polyethylene film. The results indicate that TIF can increase fumigation efficiency for perennial crop growers.

Tractor-mounted, GPS-based spot fumigation system manages Prunus replant disease

by V. Udompetaikul, Robert W. Coates, Shrinivasa K. Upadhyaya, Greg T. Browne, Mir Shafii, Matt Gillis

Abstract

A composite mapping and application system shows excellent potential to greatly reduce fumigant use prior to replanting orchards.

Our research goal was to use recent advances in global positioning system (GPS) and computer technology to apply just the right amount of fumigant where it is most needed (i.e., in a small target treatment zone in and around each tree replanting site) to control Prunus replant disease (PRD). We developed and confirmed the function of (1) GPS-based software that can be used on cleared orchard land to flexibly plan and map all of an orchard's future tree sites and associated spot fumigation treatment zones and 2) a tractor-based GPS-controlled spot fumigation system to quickly and safely treat the targeted tree site treatment zones. In trials in two almond orchards and one peach orchard, our evaluations of the composite mapping and application system, which examined spatial accuracy of the spot treatments, delivery rate accuracy of the spot treatments, and tree growth responses to the spot treatments, all indicated that GPS spot fumigation has excellent potential to greatly reduce fumigant usage while adequately managing the PRD complex.

E-Edition

Soil type, crop and irrigation technique affect nitrogen leaching to groundwater

by John Letey, Peter Vaughan

Abstract

Best management practices are proposed as being more effective and economical than tracking and reporting regulations for reducing the N load to groundwater.

Many groundwater resource in California are degraded by high concentrations of nitrate, most of which was transported to the groundwater in water percolating below the root zone of agricultural fields. Factors that affect the rate of water percolation — including soil type, crop and irrigation — along with nitrogen application influence the probability of this type of groundwater degradation. UC scientists have developed several useful tools, including the Nitrogen Hazard Index (NHI) and the ENVIRO-GRO (E-G) model, for use in developing best management practices (BMPs) to achieve high crop yields while minimizing groundwater degradation. We report the results of E-G simulations that quantify the effects of irrigation, soil type and organic and inorganic nitrogen (N) application amounts to corn yield and the amount of leached N. Simulation results indicate that a nitrate management strategy that also includes water management will be more effective in reducing N loading to groundwater. The research findings are discussed in the context of the track and report concept in comparison to the BMP approach.

News and opinion

EDITORIAL

Urban agriculture is a gateway to healthy foods

by John A. Pérez

OUTLOOK

Immigration reform and California agriculture

by Philip Martin

RESEARCH NEWS

UC Cooperative Extension helps farming sprout in the city

by Robin Meadows

General Information

About California Agriculture

by Editor

California Agriculture staffing changes

by Editors

CORRECTION

Correction

by Editors

Available from ANR: Weed Pest Identification and Monitoring Cards

by Editors

Coming up in California Agriculture: UC Cooperative Extension: A century of providing solutions for California

by Editors

Peer-reviewed research and review articles

by Sarah Stinson, Asli Mete

Abstract

CDFA-funded necropsy services provide reliable health information to owners of backyard flocks and gather much-needed data.

Testing protocol ensures the authenticity of organic fertilizers

by Fungai N.D. Mukome, Timothy A. Doane, Lucas C.R. Silva, Sanjai J. Parikh, William R. Horwath

Abstract

After analyzing 180 fertilizer materials and products labeled as organic, the authors developed a set of metrics that indicate probable adulteration by synthetic nitrogen.

Totally impermeable film (TIF) reduces emissions in perennial crop fumigation

by Suduan Gao, Bradley D. Hanson, Ruijun Qin, Jose Cabrera, James S. Gerik, Dong Wang, Greg T. Browne

Abstract

Three field trials make a case for TIF use in preplant fumigation of perennial crops.

Tractor-mounted, GPS-based spot fumigation system manages Prunus replant disease

by V. Udompetaikul, Robert W. Coates, Shrinivasa K. Upadhyaya, Greg T. Browne, Mir Shafii, Matt Gillis

Abstract

A composite mapping and application system shows excellent potential to greatly reduce fumigant use prior to replanting orchards.

E-Edition

Soil type, crop and irrigation technique affect nitrogen leaching to groundwater

by John Letey, Peter Vaughan

Abstract

Best management practices are proposed as being more effective and economical than tracking and reporting regulations for reducing the N load to groundwater.

News and opinion

General Information