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  • Author or Editor: S. C. Mason x
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Abstract

Recently matured whole leaves of tomato Lycopersicon esculentum Mill cvs. Centennial and Knox) gave the most reliable indication of total N, while NO3-N in older mature leaf petioles better reflected N availability and absorption. The NO3-N content of petioles was more indicative of N status of the plant than total N analysis of whole leaves. The NO3-N and total N contents of leaf parts generally decreased with increasing maturity. Soil solution NO3-N concentration increased exponentially with increasing N application rates. The first 45 kg N/ha increments increased soil solution NO3-N concentration only 10 ppm whereas the fourth 45 kg N/ha increment increased NO3-N concentration 40 ppm. Ninety kg N/ha application produced a concentration of 48 ppm NO3-N that resulted in a nearly maximum petiole concentration of 14,500 ppm NO3-N, indicating that this NO3-N concentration provided sufficient available N for the immediate reserve requirements for plant growth.

Open Access

Abstract

(2-Chloroethyl)phosphonic acid (ethephon) was applied at 0, 570, 1000 and 2000 ppm to muscadine grapes (Vitis rotundifolia Mich. cv. Hunt), 1, 2, or 3 days before once-over harvest. All ethephon treatments increased berry abscission and reduced skin tear due to harvest when berries were harvested 2 days or 3 days after spraying. Delaying harvest to 3 days after treatment with 2000 ppm ethephon increased berry abscission to 46% and reduced skin tear to 9% in 1977. In 1978, 2000 ppm of ethephon increased berry abscission to 29% and reduced skin rupture to 29%. Taste panels could not detect flavor difference from the ethephon treatments.

Open Access