Search Results

You are looking at 1 - 10 of 10 items for

  • Author or Editor: R. C. J. Koo x
Clear All Modify Search
Authors: and

Abstract

A 5-year field experiment planted on Astatula fine sand using ‘Hamlin,’ ‘Pineapple,’ and ‘Valencia’ orange (Citrus sinensis [L.] Osbeck) on rough lemon rootstock (Citrus jambhiri Lush.) with 4 levels each of N and K indicated that higher N rates increased fruit production and yield of soluble solids. High K applications decreased soluble solids. Increase in tree canopy area between 1968 and 1974 was related to N but not to K applications. Maximum yield response with N in all 3 cultivars was attained at 202 kg/ha/yr. ‘Hamlin’ orange showed maximum yield response to K at 167 kg/ha/yr whereas ‘Pineapple’ and ‘Valencia’ orange had maximum yield at 112 kg/ha/yr. Leaf analyses showed that increased N application resulted in higher leaf N and Mg contents but lower P and K levels. Increased K application showed higher P and K levels but lower Ca and Mg levels.

Open Access
Authors: and

Abstract

This is a report of a 4 × 4 NK factorial experiment over a 6-year period using ‘Hamlin’, ‘Pineapple,’ and ‘Valencia’ orange trees [Citrus sinensis (L.) Osbeck] on rough lemon rootstock (Citrus jambhiri Lush.) planted on Astatula f.s., formerly classified Lakeland f.s. Main effects of N and K were considered independently because interactions were not significant for most measurements. Increases in N rate increased the juice content and acid, whereas increases in K resulted in higher acid and lower soluble solids with an accompanying lower soluble solids/acid ratio. Smaller sized fruit, more green fruit, and a lower packout were a result of increased N rates. Increased K rates did not influence external characteristics of the fruit other than producing larger fruit. Rind blemishes occurred more often at the low N rate and diminished as the N rate increased. Incidence of decay in storage was greatest at the lowest N rate. Creasing was found to be significantly related to high N and low K rates.

Open Access
Authors: and

Abstract

Six year’s data with so-called ‘Temple’ orange (Citrus hybrid) on ‘Cleopatra’ mandarin rootstock (Citrus reticulata Blanco), show that increased rates of N and K increased fruit yield. P also increased yield. Spring vs. fall irrigation resulted in a significant increase in fruit production in 1 of 6 years, although slightly higher fruit production was observed every year with spring irrigation. Increased N rates resulted in higher leaf N and Mg but lower leaf P, K, and Ca. Increased K rates raised leaf K but lowered leaf Mg. The addition of P in the fertilizer resulted in higher leaf P and Ca but lower K and Mg contents. Spring irrigation induced lower K but higher Mg in certain years.

Open Access
Authors: and

Abstract

Increased N and K rates resulted in higher acid content in juice of ‘Temple’ orange (Citrus hybrid). P fertilization lowered both soluble solids and acid contents, but the influence on acid was more pronounced as it was reflected in higher soluble solids-acid ratio. High N vs. low N treatment also caused a small but consistent reduction in juice content. Spring irrigation resulted in higher soluble solids content than fall irrigation. N treatments decreased and K treatments increased both fruit size and weight; irrigation treatments showed no consistent trends. High N and spring irrigation treatments caused increased intensity of orange color in rind. Incidence of creased fruit was increased by high N, low K, and spring irrigation treatments. No consistent trends were found in fruit storage decay with grove treatments and the data were significant only in certain years.

Open Access
Authors: and

Abstract

Leaves were collected in 1974 and 1975 from mature ‘Tonnage’, ‘Lula’, ‘Taylor’, and ‘Booth 8’ avocado trees (Persea americana Mill.) on sand, muck, and calcareous rock soils and analyzed for N, P, K, Ca, Mg, Mn, Cu, Zn, and Fe. Significant differences in levels of all 9 elements in ‘Tonnage’ leaves occurred among the 3 soil types. Crop size, fertilization, soil pH, soil Ca level, and exchange capacity of the soil appeared to be important factors in the variations. Differences in concentration of N and P were not significant among the 4 cultivars but were significant for the other elements.

Open Access
Authors: and

Abstract

As leaves of ‘Tonnage’ avocado (Persea americana Mill.) increased in age, N, P, and K contents decreased, while Ca, Mg, Mn, Cu, Zn, and Fe contents were higher. A comparison of leaves from 1st and 2nd flushes showed similar trends reflected in leaf age. The basal leaf was lower in P but higher in Ca, Mg, and Cu when compared with the terminal leaf of the same twig. Only N and Cu contents were different when leaves from fruiting and nonfruiting twigs were compared. Practical application of the data in sampling avocado leaves is discussed.

Open Access
Authors: and

Abstract

As mango leaves increased in age, lower P and K contents were found, while Ca content was higher. The basal leaf was lower in N and Ca but higher in P and K contents when compared with the terminal leaf of the same shoots. Only small differences were observed when leaves were compared from fruiting and nonfruiting shoots. The practical application of data in sampling mango leaves is discussed.

Open Access

Abstract

An N rate associated with reduced fruit production substantially reduced the quantity of peel oil on a per metric ton (MT) of fruit basis and the yield of oil on a per hectare basis of ‘Pineapple’ orange (Citrus sinensis (L.) Osbeck) K had no significant effect on the peel oil content on a per ha basis, but did increase fruit production (MT/ha) and reduced the peel of oil content.

Open Access

Abstract

Arsenic (As) and lead (Pb) sprays applied to grapefruit (Citrus paradisi Macfad.) accelerate fruit maturity but do not contribute to the As and Pb content of the peel oil. The physicochemical properties of the expressed oils are influenced by this induced maturity but would occur naturally in the course of normal fruit maturation.

Open Access

Abstract

Yields and quality were compared on young bearing ‘Bearss’ lemon (Citrus limon L.) trees grown with 3 rates of N and K and 2 levels of soil moisture over a 4-year period. Increased rates of N application increased fruit production, incidence of fruit with scab, and green fruit; and decreased acid content of juice. Potassium applications increased the acid content of juice. Irrigation increased fruit size and decreased the number of green fruit after curing. A leaf N content of 2.2 to 2.6% is suggested for optimum fruit production for ‘Bearss’ lemon under Florida conditions.

Open Access