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United States Department of Agriculture

Agricultural Research Service

Research Project: PECAN CULTIVATION AND DISEASE MANAGEMENT

Location: Fruit and Nut Research

Title: What form of nitrogen do pecan trees prefer?

Author
item Wood, Bruce

Submitted to: Pecan Grower
Publication Type: Trade Journal
Publication Acceptance Date: March 15, 2011
Publication Date: April 1, 2011
Citation: Wood, B.W. 2011. What form of nitrogen do pecan trees prefer? Pecan Grower. 22(4):36-50.

Interpretive Summary: Alternate bearing, or yield instability, is the most important problem affecting the U.S. pecan industry. Stabilization of yield and quality of nutmeats produced by orchards requires new horticultural tools and management strategies. A re-evaluation of pecan’s ecophysiology and its interaction with its native habitats indicates that tree growth and development in non natural orchard habitats can be manipulated by altering the relative balance of nitrate and ammonium to which trees are exposed, with a high nitrate:ammonium ratios triggering vegetative growth and low nut production, whereas a low nitrate:ammonium ratio triggers reproductive growth and reduced vegetative growth. Evidence indicates that the nitrate:ammonium ratio is a potential horticultural tool that can be utilized to stabilize orchard yield and alternate bearing.

Technical Abstract: The most important problem affecting the U.S. pecan industry is alternate bearing, or yield instability. Stabilization of yield and quality of nutmeats produced by orchards requires new horticultural tools and management strategies. A re-evaluation of pecan’s ecophysiology and its interaction with its native habitats indicates that tree growth and development in non-natural orchard habitats can be manipulated by altering the relative balance of nitrate and ammonium to which trees are exposed, with a high nitrate:ammonium ratios triggering vegetative growth and low nut production, whereas a low nitrate:ammonium ratio triggers reproductive growth and reduced vegetative growth. Evidence indicates that the nitrate:ammonium ratio is a potential horticultural tool that can be utilized to stabilize orchard yield and alternate bearing.

Last Modified: 4/19/2014
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