Phosphorus Fertilization of Hops1
- Louis C. Boawn and
- Paul E. Rasmussen2
Hops were grown on field plots treated with five levels of phosphorus fertilization to determine the effect of P on vine growth, cone quality, and zinc nutrition. A maximum P treatment of 1,344 kg/ha, applied over a 5-year period, increased the extractable P level of the surface 20 cm of soil from 10 ppm to approximately 100 ppm. The P level in leaves and cones from this treatment was increased by approximately 0.10 to 0.15% P as compared with the no-P treatment. Increased levels of P had no observable effect on vine color and vigor or on total growth as determined by vine green weight. The critical level for P in sidearm leaves at early bloom was indicated to be below 0.25%.
The alpha acid content of cones decreased where P fertilization exceeded approximately 500 kg/ha. However, this decrease was poorly correlated with the P content of leaves, indicating the lack of a direct causal relationship.
The P treatments caused a definite reduction in the Zn concentration in leaf and cone tissues, but did not induce observable Zn deficiency symptoms.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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