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  • Author or Editor: C. K. Labanauskas x
  • HortScience x
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Abstract

Using wet-digestion as a standard, leaf samples of orange (Citrus sinensis (L.) Osbeck cv. Valencia) and Schefflera actinophylla Harms were dry-ashed at 500° and 700°C to demonstrate analytical sensitivity of the Schefflera nutrient elements to ashing temperature. Citrus leaf samples dry-ashed at 500° showed only a significant analytical loss in Fe, but dry-ashing at 700° showed substantial losses in Zn, and K. Schefflera leaf samples dry-ashed at 500° showed substantial losses in Cu, Fe, and Mn. Samples dry-ashed at 700° showed high to very high losses in Ca, Mg, Na, Zn, Cu, Mn, and Fe. Use of an analytical method established for one plant species was clearly not applicable to others without verification.

Open Access

Abstract

Zn and K loss was related to increasing temperature, and Cu, Fe, Mg, and P loss was related to the residual carbon in the ash of a standard routine check and reference sample of ‘Valencia’ orange leaves (Citrus sinensis (Linn.) Osbeck). Only Zn showed both loss due to volatilization and analytical loss related to increasing amounts of residual carbon. Mn and Na did not show a clear response to time, temperature, or sample size; B showed a response only at the highest temperature. The magnitude of differences was small, but the measured differences were very highly significant, indicating consistency due to treatment under given sets of conditions.

In a proven dry-ashing procedure widely accepted for citrus leaves in California, best results were obtained when citrus tissue materials were ashed at 550°C for 8 hr, and when sample size was not greater than 2.5 g.

Open Access

Abstract

Major nutrients removed by ‘Valencia’ orange fruit were N, K, Ca, P, and Mg. Amounts of N, Ca, and B were higher; Zn and Mn were lower than those reported for Florida oranges. Relatively small amounts of applied nutrients were found to be removed by the fruit. P, K, Ca, Mg, Zn, Mn, Cu, and Fe tended to be immobilized in the soil (either by direct application or decay of leaves and other plant parts), availability depending on soil pH. Leaching of N, largely as NO3, should always be minimized.

Open Access

Abstract

Three-year-old seedlings of Cleopatra mandarin (Citrus reticulata Blanco) and Troyer citrang [Citrus sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf] were budded to ‘Valencia’ orange (Citrus sinensis (L.) Osbeck) at 5, 15, 30, 45, 60, and 90 cm above the ground level. Fruit yield was highest from trees budded at 15 cm height above the ground and tended to decrease as budding height increased. Nutrient concentrations in the leaves of trees were affected by the height of budding, but remained in an optimum range for maximum fruit production. The different rootstocks affected the nutrient concentrations in the leaves dramatically, but they still remained in an optimum range for maximum production of oranges.

Open Access