California Agriculture, April-June 2012
Volume 66, Number 2
peer-reviewed research articles
No-tillage and high-residue practices reduce soil water evaporation
by
Jeffrey P. Mitchell , Purnendu N. Singh , Wesley W. Wallender , Daniel S. Munk , William R. Horwath , Philip Hogan , Robert Roy , Blaine R. Hanson , Jonathan F. Wroble
pp55-61, doi#10.3733/ca.v066n02p55
Abstract
Reducing tillage and maintaining crop residues on the soil surface could improve the water use efficiency of California crop production. In two field studies comparing no-tillage with standard tillage operations (following wheat silage harvest and before corn seeding), we estimated that 0.89 and 0.97 inches more water was retained in the no-tillage soil than in the tilled soil. In three field studies on residue coverage, we recorded that about 0.56, 0.58 and 0.42 inches more water was retained in residue-covered soil than in bare soil following 6 to 7 days of overhead sprinkler irrigation. Assuming a seasonal crop evapotranspiration demand of 30 inches, coupling no-tillage with practices preserving high residues could reduce summer soil evaporative losses by about 4 inches (13%). However, practical factors, including the need for different equipment and management approaches, will need to be considered before adopting these practices.
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Research and adoption of biotechnology strategies could improve California fruit and nut crops
by
Victor M. Haroldsen , Gabriel Paulino , Cecilia L. Chi-Ham , Alan B. Bennett
pp62-69, doi#10.3733/ca.v066n02p62
Abstract
California's fruit and nut tree crops represent one-third of the state's cash farm receipts and 70% of U.S. fruit and nut production. Advances in crop biotechnology and genetic engineering could help protect these valuable crops from pests and diseases and improve productivity. However, due to the difficulty of genetically engineering woody tree crops, as well as intellectual property concerns, regulatory hurdles and public perceptions about genetic engineering, biotechnology has not gained a foothold in this area of agriculture. Our survey of published genetic engineering research and issued field trial permits between 2000 and 2011 revealed that citrus and grape are the focus of most current work, and that walnut — not the more widely planted almond — is the focus among nut crops. Matching publicly funded genetic engineering research projects to a survey of the industry's top needs, we found that far less than half of the funded research has focused on the top-identified pest and disease threats. The most promising genetic engineering technology for fruit and nut tree crops may be transgrafting, which could address consumer concerns and benefit growers.
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Sidebar: Regulatory status of transgrafted plants is unclear
by
Victor M. Haroldsen , Gabriel Paulino , Cecilia L. Chi-Ham , Alan B. Bennett
pp68-69, doi#10.3733/ca.v066n02p68
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New quality index based on dry matter and acidity proposed for Hayward kiwifruit
by
Gayle M. Crisosto , Janine Hasey , Jorge A. Zegbe , Carlos H. Crisosto
pp70-75, doi#10.3733/ca.v066n02p70
Abstract
Researchers from various countries have proposed using dry matter at harvest as a worldwide quality index for Hay-ward kiwifruit, because it includes both soluble (sugars and acids) and insoluble (structural carbohydrates and starch) solids and doesn't change during post-harvest handling. Our consumer tests in 1999 and 2008 indicated that dry matter and ripe titratable acidity are related to in-store consumer acceptance of kiwifruit. In most California seasons, when ripe titratable acidity was less than 1.2%, only a dry matter greater than or equal to 15.1% was required for consumer acceptability. Our 6-year quality attribute survey of California kiwifruit at harvest and from cold storage demonstrated that dry matter and ripe soluble solids concentration were highly variable among vineyards and seasons, but ripe titratable acidity values varied more among seasons than between vineyards. Our results provide strong evidence that dry matter would be a reliable quality index candidate for California kiwifruit, especially if ripe titratable acidity were factored in.
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editorial, news, letters & science briefs
TO OUR READERS: Honoring 150 years of accessible higher education
by
Janet White
pp39, doi#10.3733/ca.v066n02p39a
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Letters
From our readers
pp39, doi#10.3733/ca.v066n02p39b
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EDITORIAL: For 150 years, UC science and agriculture transform California
by
Mark G. Yudof
pp40-41, doi#10.3733/ca.v066n02p40
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Outlook: UC's land-grant mission fuels nation's growth, prosperity
by
Rose Hayden-Smith
pp42-45, doi#10.3733/ca.v066n02p42
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UC land grants: A photo history
by
Editors
pp46-49, doi#10.3733/ca.v066n02p46
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Report seeks solutions for nitrate in drinking water
by
Editors
pp51, doi#10.3733/ca.v066n02p51
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UC leads effort to protect California forests from catastrophic fire
by
Jeannette Warnert
pp52-53, doi#10.3733/ca.v066n02p52
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Conservation tillage achieves record acreage, yields
by
Jeannette Warnert , Editors
pp54, doi#10.3733/ca.v066n02p54
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General Information
About California Agriculture
by
Editor
pp50, doi#10.3733/ca.v066n02p50
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AVAILABLE from ANR
Editors
pp76, doi#10.3733/ca.v066n02p76a
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COMING UP in California Agriculture
Editors
pp76, doi#10.3733/ca.v066n02p76b
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