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  • Author or Editor: A.A. Csizinszky x
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Optimum economic yield is produced when nutrients in the proper amounts are supplied to the crop. Crop nutrient requirements (CNR) of essential elements have been determined for the major vegetables produced in Florida. However, for minor crops, such as muskmelon, little research has been conducted to determine the CNR, especially potassium. In many vegetables, yield has responded to increasing K rates when other elements were not limiting. Our objective was to determine the K fertility requirement for optimum yield of muskmelon and to evaluate the Mehlich-1 soil test calibration for soil testing low in K (<20 mg·kg–1). Experiments were conducted in the spring and fall seasons of 1995. Potassium at five rates (0, 56, 112, 168, and 224 kg·ha–1) was injected weekly, approximating the growth curve of `Galia' and `Mission'. There were significant yield responses to K fertilization for both cultivars during both seasons. During spring, average marketable yield was 14.5, 26.1, 31.9, 31.5, and 36.3 Mg·ha–1 and for fall, average marketable yield was 15.8, 32.9, 37.8, 37.2, and 36.4 Mg·ha–1 for the previously described K treatments, respectively. The cultivar response for both seasons was described by a linear-plateau model. In spring, yield was maximized with K at 116.8 and 76.3 kg·ha–1 for `Galia' and `Mission', respectively. In fall, K at 73.3 and 68.3 kg·ha–1 produced the peak response for the same cultivars. These results indicate that maximum yield of muskmelon in Florida can be obtained at considerably less K than the current recommendation of 140 kg·ha–1.

Free access

Combinations ofvarious vegetable crop species grown in multiple-cropping sequences using microirrigation on a sandy soil were evaluated for production potential and changes in normal cultural management An initial fall-season fresh-market tomato crop was followed immediately by a winter-season crucifer crop (cauliflower, broccoli, or cabbage), which was followed by a spring-season cucurbit crop (cucumber, zucchini squash, or muskmelon). Studies were conducted over a 3-year period in southwestem Florida. Results showed that when cropping sequences were compared on a basis of a derived relative value index (RVI), the sequence of tomato-cauliflower-zucchini squash significantly outperformed other sequences. Several management concerns particular to the production system (crop residue removal and interference, plastic mulch deterioration and damage, and weed control) were identified and discussed. The potential savings when cropping sequences are compared to individual crop production resulted in net savings (dollar savings less additional production costs) that ranged from $565 to $1212/acre ($1396 to $2993/ha) and $614 to $1316/acre ($1516 to $3251/ha) for the 1986-87 and 1988-89 seasons, respectively.

Free access

Abstract

First introduced for strawberries in the late 1950s, polyethylene mulch has been used widely for vegetable culture in Florida (4, 5). Currently, about 40,000 ha of vegetables are produced in Florida using polyethylene ground mulches. A full-bed mulch system is used for most of the tomato, pepper, and strawberry crops in Florida (2, 3).

Open Access

Tomato (Lycopersicon esculentum Mill.) was grown with polyethylene mulch at five locations during a total of nine seasons to evaluate the effects of K source and K rate on fruit yield and leaf K concentration with drip and subsurface irrigation. K sources evaluated were KCl, K2SO4, and KNO3, and K rates varied from 0 to 400 kg·ha-1. Preplant soil K concentrations by Mehlich-1 extraction on the sandy soils and loamy sands used in the study varied from 12 mg·kg-1 (very low) to 60 mg·kg-1 (medium). In seven of the eight studies, K source did not significantly influence fruit yield or leaf K concentration. In the other study with subsurface irrigation at Bradenton in Spring 1992, marketable yields were significantly higher with KNO3 than with KCl as the K source. Tomato fruit yield responded to the application of K in all studies. At Gainesville, Quincy, and Live Oak, with drip irrigation on soils testing low to medium in K, maximum yields were produced with 75 to 150 kg·ha-1 K where the K was broadcast preplant. These rates were 25% to 30% higher than those predicted by soil test. At Bradenton and West Palm Beach on soils testing low to very low in K, where all or part of the K was applied in double bands on the bed shoulder with subsurface irrigation, yield responses were obtained to 225 to 300 kg·ha-1 K. These rates exceeded the maximum recommended K rate of 150 kg·ha-1. Tomato leaf tissue K concentrations increased linearly with increased rates of K application, but were not influenced by K source. These data suggest that the recommendation for K on soils testing low in K be increased from 150 to 210 kg·ha-1 and that this increase should suffice for tomatoes grown with either drip or subsurface irrigation.

Free access

Abstract

Field studies were conducted over three seasons to determine the effect of N and K on susceptibility of tomato to bacterial spot. A factorial randomized complete block design consisting of four rates of N (167, 334, 501, and 668 kg·ha–1) and three rates of K (334, 668, and 1335 kg·ha–1) were used. Liquid fertilizer was injected via trickle irrigation. Increasing N rates reduced disease severity, whereas the effect of increasing K was inconsistent from season to season. The concentration of N in leaf tissue showed a significant negative correlation with disease severity, whereas the concentration of Ca in leaf tissue exhibited significant positive correlation with disease severity and negative correlation with N rate during two seasons of data collection.

Open Access