Date of Graduation

Spring 2017

Degree

Master of Science in Plant Science (Agriculture)

Department

School of Agriculture

Committee Chair

Melissa Remley

Keywords

phosphorus, grazing, winter annual forages, grass tetany ratio, hydroponics, wheat, oat, cereal rye

Subject Categories

Plant Sciences

Abstract

Adequate soil phosphorus (P) is critical for the growth and nutrient content of forages for grazing animals. On low fertility soils, tall fescue responds to P fertilization with increased yields and improved leaf nutrient contents of P, magnesium (Mg), calcium (Ca), and potassium (K) in winter months. My objective was to examine the effect of P availability on growth and leaf nutrients in annual cereal grains commonly grown for winter forage. Soft red winter wheat (Triticum aestivum), oat (Avena sativa), and cereal rye (Secale cereale) were grown hydroponically in greenhouse conditions in complete nutrient solutions with varying P concentrations of 0, 200, 400, and 800 μM P (3 blocks, 3 replicates per block). After 32 days, plants were harvested, dried, weighed, and analyzed for P, Mg, Ca, and K content. Shoot growth of all three species increased from 0 to 200 μM P, however only wheat shoots increased incrementally with P treatment concentrations. Leaf P also responded to P treatments incrementally in all three species. Leaf Ca increased from 200 and 800 μM P in cereal rye, while Mg increased from 400 and 800 μM P (using 1:4 Na2HPO4 and NaH2PO4) in wheat and cereal rye. No changes in leaf K were found in any of the grain species in 200 μM P or greater. These findings support the hypothesis that increased P availability can influence nutrient concentrations in leaf tissue of winter annual forage species.

Copyright

© Jerri Lynn Dodson

Open Access

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