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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Phosphorus nutrition of Ilex crenata 'Helleri' grown in a pine bark medium

Yeager, Thomas H. January 1981 (has links)
The purpose of this research was to characterize the phosphorus nutrition of Ilex crenata 'Helleri' and pine bark P relationships. Branched liners of 'Helleri' holly were grown in a pine bark medium in which 0, 5, 10, 15, 20, 25, or 30 ppm P were maintained. Shoot dry weight increased as the pine bark P level increased to 10 ppm P, while root dry weight decreased with increasing pine bark P levels. Total mg of P in shoot tissues continued to increase with P treatments higher than 10 ppm, indicating luxury consumption of P. Total mg of P in root tissues increased to the 10 ppm P treatment. Total µg of Fe, Cu, and Zn in shoot tissues followed the dry weight response, increasing to the 5-10 ppm P treatment then tending to decrease as pine bark P levels increased. Root tissue Fe was erratic while Cu did not vary with treatment and Zn decreased with increasing pine bark P levels. Total µg of Mn in shoot tissues increased with P treatments while total µg of Mn in root tissues decreased with increasing pine bark P levels. Dry shoot weights of 'Helleri' holly grown in a pine bark medium amended with either 270, 540, or 810 g/m³ of P or fertilized with 10 ppm P were not different while root dry weights decreased with increasing pine bark P levels. Water extractable P for the 810 g/m³ treatment decreased 245 ppm during the experiment and by week 5 was below 10 ppm. Amending the pine bark medium with 270 g/m³ of P did not increase the dry shoot weight of ‘Helleri’ holly when subsequently fertilized with a complete slow-release granular or water soluble fertilizer. The pine bark medium contained indigenous P which leached rapidly. When ‘Helleri’ holly were fertilized with a nutrient solution without P, 0.08 mg of indigenous P were absorbed. The pine bark adsorbed 7.5 µg of P per g of pine bark when equilibrated with a 10 ppm P nutrient solution. These studies indicate that maintaining 10 ppm P in the pine bark medium results in the greatest dry weight of 'Helleri' holly. A stable pine bark P level was not attained with superphosphate-amended pine bark, thus superphosphate is not recommended as a P source. Pine bark P relationships revealed that ‘Helleri’ holly absorbed indigenous P while a negligible amount of P was bound by the pine bark compared to the amount of P used by a ‘Helleri’ holly grown in a 1 liter container. / Ph. D.

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