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- Author or Editor: S. J. Locascio x
Tomatoes (Lycopersicon esculentum Mill.) were grown during two seasons at two locations on fine sands and fine sandy loam soils to study the influence of water quantity, frequency of water application, and timing of N and K application for polyethylene-mulched, trickle-irrigated fresh-market tomatoes. Water quantities were 0.50 and 1.0 times pan evaporation applied one or three times daily. Nitrogen and K were applied 100% preplant or 40% applied preplant and 60% applied with trickle irrigation. Higher tomato leaf tissue N and K concentrations in one of the two seasons and higher fruit yields were obtained with 0.5 than with 1.0 time pan water evaporation on a fine sand at Gainesville, Fla. On a fine sandy loam soil at Quincy, fruit yields were higher in a relatively dry season with the higher water quantity and not influenced by the water quantity applied in the second relatively wet season. The number of daily water applications (one vs. three) at both locations had no effect on N and K uptake or fruit yields. Time of N and K applications had no effect on early yields, but total yields were higher with split than all preplant-applied N and K on the fine sandy soil. Split applications of fertilizer resulted in greater yields of extra-large fruit at mid-season and of extra large and large fruit at late harvest than all preplant-applied fertilizer. On the fine sandy loam soil, time of fertilizer application had no effect on yield.
Tomatoes (var. Sunny) were grown using drip irrigation and polyethylene mulch in a three-year study with water applied to plots at 0, 0.25, 0.50, 0.75 and 1.00 times pan evaporation in one application per day. Breaker stage fruit were harvested twice each season at 7 to 10 day intervals and evaluated after storage for 11 days at 20C. Response to water application varied with seasonal rainfall levels. Soluble solids levels decreased with increasing water quantity only in the first (relatively dry) season, while titratable acidity levels decreased with increasing water in all three seasons. Fruit color was not affected by water quantity in the first season but hue angle increased and chroma decreased with increasing water in the second and third seasons. Decay incidence (associated primarily with blossom end rot) was higher in nonirrigated than irrigated treatments and in the second harvests. Internal white tissue, a symptom of irregular ripening, was more common in irrigated treatments and in the wetter second and third seasons
Strawberry (Fragaria × ananassa Dutch.) response to trickle irrigation was compared with overhead and no irrigation. Fertilizer rates were 94-55-104 to 202-118-223 kg/ha N-P-K with 0, 50, and 100% of the N and K applied with trickle irrigation. The remaining fertilizer for trickle and all for overhead and non-irrigated treatments was applied preplant. Fruit yields were increased 34% with overhead irrigation and 37% with trickle irrigation above that for non-irrigated treatments. With 0 and 50% of the N and K applied in daily or weekly increments with trickle irrigation, fruit yields were 2 and 20% greater than with overhead irrigation, 30 and 58% greater than with no irrigation, respectively. The N levels of leaf tissue samples were not influenced by treatment. Leaf K levels were significantly higher with trickle irrigation than with overhead irrigation or check treatments. Soil value for total soluble salts, K and NO3 were significantly lower with trickle irrigation than with overhead or no irrigation treatments.
`Equinox' tomatoes (Lycopersicon esculentum Mill.) were grown during the springs of 2001 and 2002 with black polyethylene-mulch and drip irrigation on an Arredondo fine sand in Gainesville, Fla., to study the influence of water quantity, Ca source, and reduced K on incidence of blossom-end rot (BER), marketable fruit yield, and fruit and leaf Ca concentration. Tensiometers were used to schedule irrigation in main plots when the soil matric potential reached 10 or 25 kPa. Subplot nutritional treatments were no added Ca, Ca(NO3)2, Ca thiosulfate, CaCl2, CaSO4, and K rate reduced by 50%. Interactions between year and treatment were significant. During 2001, total marketable yields were higher with Ca(NO3)2 or CaCl2 compared to plants that received Ca thiosulfate and were higher from plants irrigated at 10 kPa than irrigated at 25 kPa. Number and weight of BER fruit were lower with Ca(NO3)2 and reduced K than with no added Ca and CaSO4. Leaf and fruit Ca concentrations were generally higher with Ca(NO3)2 compared to all other nutritional treatments. Leaf and fruit Ca concentrations were generally higher from plants irrigated at 10 kPa than at 25 kPa. The reduction of NH4 +-N, by the supply of N as NO3 -, and the addition of supplemental Ca reduced the incidence of BER, and increased the leaf and fruit Ca concentrations. During 2002, marketable yields were higher with CaSO4 than with CaCl2 and reduced K. Weight and number of BER fruit were lower with irrigation at 10 kPa than at 25 kPa. Leaf and fruit Ca concentrations were higher or similar from plants that received Ca(NO3)2 than with all other nutritional treatments. During the 2002 season, rainfall was less and temperatures and daily evapotranspiration (ET) were higher than in the 2001 season. In the 2002 season, 3.28 × 106 L·ha-1 of irrigation was applied as compared to 1.58 × 106 L·ha-1 in 2001. With an average Ca concentration of 76 mg·L-1 in the irrigation water, much more Ca was applied during the higher ET 2002 season. With the higher transpiration and temperature, water uptake and hence, Ca uptake were increased. During both seasons, the lowest Ca concentration was observed at the blossom end of the fruit and the highest Ca at the stem end of the fruit. Fruit Ca concentrations were lower and BER was 5 times higher in the lower ET, higher rainfall (lower irrigation) 2001 season compared to the higher ET, lower rainfall (higher irrigation) 2002 season. These data support that BER was a symptom of Ca deficiency and this deficiency was aggravated by high rainfall, low ET, and the resulting reduced irrigation applied and reduced Ca uptake.
Strawberries (Fragaria × ananassa Dutch.) were grown during 2 seasons to evaluate 5 N sources and 2 times of N and K application using trickle irrigation with N and K rates of 134 and 149 kg ha−1, respectively. Fruit yields were influenced by significant interactions between N-source and time of N and K application during both seasons. With 100% of the N and K applied preplant, marketable fruit number and weight were significantly greater with sulfur coated urea (SCU) or isobutylidene diurea (IBDU) than with urea, NH4NO3 or KNO3 + Ca(NO3)2 as the N sources. With 40% of the N from the above 5 sources applied preplant and 60% of the N and K supplied with the trickle irrigation from NH4NO3 + K2SO4 or KNO3 + Ca(NO3)2, production was similar with all N sources. Leaf tissue N and K concentrations were not influenced consistently by N source. During both seasons, leaf N concentrations were higher with the split than with the 100% preplant treatments.
The effects of plant and row spacing, mulch, and fertilizer rate on ‘Charleston Gray’ watermelons [Citrullus lanatus (Thunb.) Matsum. & Nakai] were evaluated in field studies on 2 Florida sandy soils. Marketable fruit yields decreased while yield/plant and mean fruit weight increased with an increase in plant spacing from 0.6 to 2.4 m and row spacing from 1.5 to 4.5 m. On a Kanapaha sandy soil with adequate water, yields and mean fruit weights were higher with mulch than without and with 1680 than 840 kg/ha of 12-7-13 (N-P-K) fertilizer.
Tomato (Lycopersicon esculentum Mill.) was grown on fine sand and fine sandy loam soils at two sites to evaluate effects of N and K fertilization practices on petiole fresh sap N and K concentrations and to determine N and K sufficiency ranges. Treatments included applying N (196 kg·ha–1) and K (112 kg·ha–1) either 0%, 40%, or 100% preplant. With 0% or 40% preplant treatments, the remaining N and K was injected through the drip irrigation system in six or 12 equal weekly amounts or by a variable injection rate with most of the N and K injected between weeks 5 and 10 of the season. Petiole sap K concentration declined during the season, but was not greatly affected by treatment. Petiole N decreased over the season from 1100 to 200 mg NO3-N/liter and decrease was greater for preplant N treatments. Petiole N was correlated with tomato yield, especially for petiole N measured in the period of 5 to 10 weeks after transplanting.
Tomato (Lycopersicon esculentum Mill.) was grown with drip irrigation on a fine sand and on a fine sandy loam to evaluate the effect of N and K time of application on yield. On the sandy soil, 196–112 kg of N–K/ha was applied with 0%, 40%, or 100% preplant with 100% or 60% applied in six or 12 equal or in 12-week variable applications. Marketable fruit yields were lowest with 100% preplant, intermediate with 100% drip-applied, and highest with 40% preplant with 60% drip-applied. With 100% drip-applied, yields were highest with 12 even than with six even weekly applications or with 12 variable N and K applications. With the 40% preplant, timing of application had little effect on yield. On the sandy loam soil in 1993, where only N was applied (196 kg·ha–1), yields were highest with 100% preplant, intermediate with 40% preplant and 60% drip-applied, and lowest with all N drip-applied. In 1994, when excessive rains occurred, yields were similar with all preplant and with split-N applications.
Strawberries (Fragaria ×ananassa, Duch) were grown in the annual hill system at four locations in Florida to compare the effects of standard black low density polyethylene (LDPE) mulch and red reflective mulch (SMR-red) on fruit size and production. Marketable fruit size was not affected by mulch color. Early and total marketable fruit yields were not affected by mulch color at Bradenton, but yields were significantly higher at Gainesville with red than black mulch, and were significantly higher with black than red mulch at Quincy and Hastings. Soil temperatures under the black mulch were significantly higher than red mulch at Hastings but significantly higher under red than black mulch at Gainesville. Mean soil temperatures at soil depths of 5 to 25 cm ranged from 0.2 to 0.4 °C Reflected photosynthetically active radiation values at 25 and 50 cm above the mulch were higher earlier in the season and decreased as the season progressed. Within a month after transplanting when foliage covered about 10% of the mulch, reflections were lower and similar at both heights with black mulch than red and were higher at 25 than 50 cm with red mulch. Data indicate that there was not a consistent advantage of the use of this red mulch over black mulch at four locations in Florida.
Green `Jupiter' bell peppers (Capsicum annuum L.) were grown in the spring and fall seasons of 1994 on polyethylene mulch with drip irrigation. Seedlings were planted on three dates in each season, either 2 weeks (spring) or 1 week (fall) apart, with N applied at rates of 0, 100, 200, or 400 kg·ha–1. Primary fruit were harvested upon reaching full size (diameter) and the bioyield-point (which reflects bruising susceptibility) measured at the fruit shoulder with an Instron machine; pericarp thickness was measured adjacent to the area where bioyield-point was measured. Dry weight of the fruit tissue was measured in the fall only. Bioyield force decreased with increasing N rate and increased with later planting time in the fall, but did not change with N rate and decreased only slightly with planting time in the spring. Pericarp thickness increased with N rate in both spring and fall, but increased with planting time in the spring while decreasing in the fall. Dry matter increased with planting time, but decreased with N rate in the fall peppers. These results indicate that bioyield force is not controlled by pericarp thickness, but rather may be more closely related to cell size or cell wall thickness, as suggested by dry weight differences.