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Bohan Liu and Peter J. Landschoot

Impaired water quality in the Chesapeake Bay and other surface waters due to excess phosphorus (P) is receiving scrutiny from state and federal environmental regulatory agencies. Although agricultural operations are considered the largest single

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Tjasa B. Tiefengraber, Kitren G. Weis, George C. Martin, and Barbara D. Webster

Ethephon reduces olive fruit removal force but also results in leaf loss when used as a harvest fruit loosening agent and in reduction of flower production in the subsequent year. Phosphorus (P) has been implicated in the fruit loosening process. Nuclear magnetic resonance analyses indicate that P accumulates rapidly in olive leaf explant abscission zones. P also causes ethylene evolution prior to abscission; this effect appears to be direct. In combination with AOA an ethylene synthesis inhibitor, P accelerates `Manzanillo' leaf explants abscission, inducing significant abscission 3 days after treatment. These results will assist in development of a P use strategy that leads to fruit but not leaf abscission.

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Rafael Urrea-López, Rocío I. Díaz de la Garza, and Juan I. Valiente-Banuet

phosphorus (P) ( Halvin et al., 2005 ). In Capsicum, N deficiency affects plant growth, yield, and the accumulation of secondary metabolites (e.g., capsaicin) ( Johnson and Decoteau, 1996 ; Medina-Lara et al., 2008 ). Similarly, P deficiency reduces the

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Thomas A. Obreza and Arnold Schumann

. To remain sustainable, the industry must improve nitrogen (N) and phosphorus (P) fertilizer use efficiency because total maximum daily load implementation will limit N and/or P loading in watersheds where citrus is grown. The objectives of this

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John Watson, François Hébert, Eric M. Lyons, Theo Blom, and Katerina S. Jordan

turfgrass establishment are root zone mixture, seeding rate, and phosphorus fertility. Murphy et al. (2001) found that smaller particle-sized sands result in good establishment of creeping bentgrass and a later study by the same author ( Murphy et al

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Kiyoshi Banno and George C. Martin

Olive fruit harvest by mechanical shaking continues to be limited by poor fruit removal - less than 60% removal for most varieties. Whereas foliar spray of ethylene releasing compounds such as ethephon increases fruit removal percent, excessive leaf loss following treatment precludes commercial acceptance of the treatment. A classic case of serendipity has led to the testing of phosphorus as an olive fruit loosening agent. Na2 HPO4 at 25 mM applied via the cut stem of explants leads to massive leaf and fruit abscission. When the P source is applied at 100 mM foliar spray, fruit removal is accomplished with minimal leaf loss. Results of this investigation will cover P source, concentration, genera with abscission response and some indication of mechanism of action.

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Timothy K. Broschat

Ixoras (Ixora L.) growing in calcareous sandy soils are highly susceptible to a reddish leaf spot disorder. Symptoms appear on the oldest leaves of a shoot and consist of irregular diffuse brownish-red blotches on slightly chlorotic leaves. Symptoms of K deficiency, P deficiency, and both K and P deficiency were induced in container-grown Ixora `Nora Grant' by withholding the appropriate element from the fertilization regime. Potassium-deficient ixoras showed sharply delimited necrotic spotting on the oldest leaves, were stunted in overall size, and retained fewer leaves per shoot than control plants. Phosphorus-deficient plants showed no spotting, but had uniformly brownish-red older leaves and olive-green younger foliage. Plants deficient in both elements displayed symptoms similar to those observed on landscape plants. Symptomatic experimental and landscape ixoras all had low foliar concentrations of both K and P.

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Xiangguang Duan, Wei Liu, Xiaojing Wang, Lixia Zhang, Shuguang Liu, Lili Guo, Dalong Guo, and Xiaogai Hou

,” and is similar to oil from olive and camellia, which are among the most popularized and healthiest cooking oils in the world ( Liang et al., 2017 ). Phosphorus plays an important role in crop growth, yield, and quality formation. The availability of

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Kelly Ross, Gerry Neilsen, and Denise Neilsen

cultivar. Phosphorus content assessment. Leaf and fruit P concentrations were measured annually for all plots. In preparation for P analysis of leaf samples, the leaves were oven-dried at 65 °C and ground in a stainless steel mill. In preparation for P

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Sarah A. White

concentration of nutrients in container nursery (crops produced in open systems, without permanent cover) effluent can range from 0.1 to 135 mg·L −1 nitrate-nitrogen (NO 3 -N) and 0.01 to 20 mg·L −1 phosphate-phosphorus (PO 4 -P) ( Huett et al., 2005 ; Taylor