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.
Broccoli (Brassica oleracea L. var. italica), followed by tomato (Lycopersicon esculentum Mill) or squash (Cucurbita pepo L. var. melopepo), and then broccoli were produced in succession re-using the same polyethylene-mulched beds at two locations with different soil types. First-crop broccoli yield was earlier and greater with drip than with overhead irrigation and increased as N-K rate increased from 135-202 to 270-404 kg·ha-1. On a tine sandy soil, yields of second and third crops produced with residual or concurrent fertilization increased with an increase in N-K rate. On a loamy fine sandy soil, yields also increased as the rate of residual N-K increased; yields of second and third crops did not respond to rate of concurrently applied N-K, but were higher with concurrent than with residual fertilization, except total tomato yields were similar with either application time. With drip irrigation and concurrent weekly fertigation, yields equalled or exceeded those obtained with preplant fertilization and overhead irrigation.
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.
Experiments were conducted to evaluate the response of carrots (Daucus carota L.) to target plant densities of 39, 59, and 79 plants per meter of band with various row arrangements (2 band/bed with 2, 3, or 4 seeded rows/band with 3.8 to 11.4 cm between rows) on a Landerhill muck soil. Marketable and total carrot yields increased linearly with increased plant density from 24 to 85 plants per square meter. In 2 of 3 experiments, row arrangement significantly influenced yield; greatest yields were obtained when spacing between rows in a band was greater than 3.8 cm, indicating some advantage to increasing the distance between rows. Mean length and diameter of marketable roots decreased linearly with increased plant density. Length and diameter of marketable carrots were influenced by row arrangement in one of the 3 experiments. Carrots grown in rows spaced more than 3.8 cm apart were longer and had a greater diameter than did carrots grown with 3.8 cm between rows.
Plant growth and fruit yield were enhanced by broadcast as compared with band applications of either N-P-K fertilizer or micronutrients. Plant dry wt were similar with applications of either CuSO4-5H2O at 4 and 8 lb./acre Cu or complete micronutrient frit (FTE 503) at 30 and 60 lb./acre in 2 seasons. In 1 season, fruit yields were significantly higher where CUSO4 was used. Increases in rate of either micronutrient source resulted in increased fruit yields where applications were broadcast but a decrease where banded. These responses to increased micronutrient rates were related to an increase in micronutrient efficiency with the broadcast placement and to a toxicity with the band placement.
`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.
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.
Isobutylidene diurea (IBDU) and sulfur-coated urea (SCU) alone or in combinations with NH4NO3 were evaluated as N sources for potatoes (Solanum tuberosum L.) on 2 sandy soils. Nitrogen was applied either all preplant or in split application at 134 or 201 kg N/ha. Tuber yields were highest with NH4NO3 alone or with NH4NO3 combined with IBDU or SCU, and were lowest with 100% IBDU and SCU. Marketable yields obtained with NH4NO3 were 25% and 27% higher than with 100% IBDU and SCU, respectively. Marketable and total yields increased and tuber specific gravity decreased slightly with increased N. Split applications of N increased marketable and total yields at one location. Leaf N, Mg, and Ca concentrations were higher and K was lower with NH4NO3 alone or with NH4NO3 with IBDU or SCU than with IBDU and SCU. Nitrogen sources had no significant effect on soil total soluble salts, NO3-N, or NH4-N, 7 and 12 weeks after fertilization.
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.