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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #259632
Title: Nutrient uptake and loss by container-grown deciduous and evergreen Rhododendron nursery plants

Author
item Scagel, Carolyn
item BI, GUIHONG - Mississippi State University
item FUCHIGAMI, LESLIE - Oregon State University
item REGAN, RICHARD - Oregon State University

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2010
Publication Date: 2/1/2011
Citation: Scagel, C.F., Bi, G., Fuchigami, L.H., Regan, R.P. 2011. Nutrient uptake and loss by container-grown deciduous and evergreen Rhododendron nursery plants. HortScience. 46(2):296-305.

Interpretive Summary: Increasing N-availability in container production of woody perennial nursery crops may not require proportional increases in availability of other nutrients; however, lowering N-availability may decrease the ability of plants to take up other nutrients. Determining rates of nutrient uptake in relationship to N-availability is useful for developing fertilizer management strategies that strive to decrease fertilizer use by synchronizing the availability of nutrients with plant demand. The influence of N-availability in the growing substrate on plant uptake and demand for other essential nutrients was evaluated from May 2005 to February 2006 in container-grown evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) and deciduous Rhododendron ‘Gibraltar’ (AZ). Changes in nutrient uptake and allocation to different structures and differences in nutrient uptake efficiency, root absorption capacity, above ground nutrient demand, and nutrient use efficiency are discussed in terms of their implications to fertilizer management in container production of Rhododendron. Increased N availability increased uptake rate all nutrients, and enhanced late season uptake of several nutrients, and increased the rate of nutrient loss during the winter. Results indicate that when adding N to container-grown Rhododendron fertilizers with higher ratios of N/P (PJM, AZ), N/Ca (PJM, ER), N/B (PJM AZ), N/Cu (PJM, ER), and N/Fe (PJM, ER) and lower ratios of N/K (PJM, ER, AZ), N/S (PJM, ER, AZ), N/Ca (AZ), N/B (ER), N/Mn (AZ), and N/Zn (ER) may be needed in order to optimize growth and minimize nutrient inputs and potential losses to the environment.

Technical Abstract: The influence of N fertilizer application on plant uptake and demand for other nutrients was evaluated from May 2005 to February 2006 in container-grown evergreen Rhododendron ‘P.J.M. Compact’ (PJM) and ‘English Roseum’ (ER) and deciduous Rhododendron ‘Gibraltar’ (AZ). Increased N-availability increased uptake of all nutrients, enhanced late season uptake of many of nutrients, and increased loss of many nutrients during the winter. Growth rate and potential for growth during the following year influenced the length of time that container-grown Rhododendron take up nutrients into autumn. Plants with a greater potential for rapid growth may be more capable of later-season nutrient uptake than plants with slower growth rates. N-availability also altered uptake ratios between N and several nutrients, indicating that when adding N to container-grown Rhododendron fertilizers with higher ratios of N/P (PJM, AZ), N/Ca (PJM, ER), N/B (PJM AZ), N/Cu (PJM, ER), and N/Fe (PJM, ER) and lower ratios of N/K (PJM, ER, AZ), N/S (PJM, ER, AZ), N/Ca (AZ), N/B (ER), N/Mn (AZ), and N/Zn (ER) may be needed in order to optimize growth and minimize nutrient inputs. Increasing N-availability in the growing substrate altered uptake efficiency, root absorption capacity, aboveground demand, and nutrient use efficiency for several nutrients, indicating that changes in N management practices need to consider how altering N application rates influence the plants ability to take up and use other nutrients. The estimated rates of nutrient uptake in relationship to N-availability will be useful in developing fertilizer management strategies that strive to decrease fertilizer use by synchronizing the availability of nutrients with plant demand. Our results indicate that nutrient management strategies for perennial crops, such as Rhododendron, need to take into consideration not only the nutrient demand for current growth, but also how to optimize nutrient availability for uptake that contributes to future growth potential and end-product quality.