Challenges and Opportunities for Extension Educators Involved in Best Management Practices

Simonne, Eric H.; Ozores-Hampton, Mónica

doi:10.21273/horttech.16.3.0403

Cited by 6 publications

(5 citation statements)

References 11 publications

(8 reference statements)

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“…Despite these BMP recommendations, some tomato producers still apply N rates that range between 290 and 470 kg · ha -1 of N which is well above the UF/IFAS-recommended rate (Cantliffe et al, 2009). These higher N rates may be ''justified'' by: 1) the longer crop seasons (16, 20, or 18 weeks in south Florida for fall, winter, and spring plantings compared with 13 weeks in north Florida for spring plantings), 2) temporary water table rises during heavy rainfall periods and/or for frost protection events, and 3) the soil moisture conditions, more conducive to denitrification (Simonne and Morgant, 2005;Simonne and Ozores-Hampton, 2006). Although, studies on tomato yield response to N rates have been documented in the past and recently compiled by Hochmuth and Hanlon (2014), few studies have estimated the crop N, P, and K accumulation and partitioning, or have used the principle of the critical N concentration (%N crit ), defined as the minimum N concentration in the aerial biomass required for maximum growth (Greenwood et al, 1991), to evaluate the UF/ IFAS N recommended rate.…”

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confidence: 99%

Effects of Nitrogen Rates on Nitrogen, Phosphorous, and Potassium Partitioning, Accumulation, and Use Efficiency in Seepage-irrigated Fresh Market Tomatoes

Ozores-Hampton¹,

Gioia²,

Sato³

et al. 2015

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Florida had the largest fresh-market tomato (Solanum lycopersicum L.) production in the United States, with a value of $437 million and 13,355 ha harvested in 2014. Despite the development of Best Management Practices (BMPs) and University of Florida/Institute of Food and Agricultural Sciences (UF/IFAS) fertilizer recommendations, tomato growers often use fertilizer rates above the recommended ones, especially when seepage irrigation is used and a longer growing season is foreseen. If a mass balance of N–P–K partitioning could be made in field conditions, a better understanding of nutrition applications could be reached. Therefore, a field study was conducted on seepage-irrigated tomato on a commercial farm in southwest Florida, during the spring and winter season of 2006 to evaluate the nitrogen (N) rate and season effects on tomato plant growth, fruit yield, N, phosphorous (P), and potassium (K) accumulation and use efficiency. The UF/IFAS N-recommended rate (224 kg·ha−1) was compared with a commercial grower (CG) rate (358 kg·ha−1). Both N rates were incorporated at bedding with 61 and 553 kg·ha−1 of P and K, respectively. Fruit yield and plant growth were measured and roots, stems, leaves, and fruit samples were analyzed to determine total N, P, and K content and accumulation in different plant parts. Nutrient recovery (REC) and the partial factor of productivity of applied nutrients (PFP) were calculated for each N rate. In the spring, 120 days after transplanting, plants dry biomass was 11.5% higher (P = 0.01) in the CG N rate than with UF/IFAS N rate, while no significant differences were observed in the winter season. In the spring, N, P, and K accumulation were 250, 56, and 285 kg·ha−1 in plants grown with CG N rate and were significantly lower (23%, 5%, and 23%, respectively) with the UF/IFAS N rate, respectively. In the winter, total N accumulation was 231 kg·ha−1 in plants fertilized at CG N rate and significantly lower (16%) with the UF/IFAS N rate. N rate did not significantly affect P and K accumulation, which were on average 64 and 312 kg·ha−1, respectively. Marketable fruit yield was significantly higher (P = 0.03) with CG N rate than with UF/IFAS N rate (91.1 vs. 81.5 Mg·ha−1), and was significantly higher (P = 0.03) in the spring than in the winter (100.8 vs. 71.8 Mg·ha−1). The NREC was significantly higher (P = 0.01) with the UF/IFAS N rate than with CG N rate and was not significantly affected (P = 0.94) by seasons. The PFPN was significantly higher (P = 0.001) with the UF/IFAS N-rate than with CG N-rate, and was significantly higher (P = 0.04) in the spring than in the winter season. These results suggest that current UF/IFAS N recommendations are more conservative of N and this should lead to reduced leaching potential but, UF/IFAS recommendations must be season specific due to the difference in environmental conditions of fruit maturation in cooler weather of the winter season compared with a warmer environment of the spring season.

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confidence: 99%

Effects of Nitrogen Rates on Nitrogen, Phosphorous, and Potassium Partitioning, Accumulation, and Use Efficiency in Seepage-irrigated Fresh Market Tomatoes

Ozores-Hampton¹,

Gioia²,

Sato³

et al. 2015

horts

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“…Tomato growers typically follow irrigation recommendations, but they tend to use fertilizer rates above these recommended ones (Cantliffe et al, 2006). Numerous studies reported that extra fertilizer application can be justified in conditions such as temporary water table rises during heavy rainfall periods and/or for frost protection events, different lengths of growing season or with the use of vigorous hybrid varieties, and/or denitrifing conditions typical under seepage irrigation in southwest Florida (Simonne and Ozores-Hampton, 2006).…”

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Nitrogen Rates Effects on the Yield, Nutritional Status, Fruit Quality, and Profitability of Tomato Grown in the Spring with Subsurface Irrigation

Ozores-Hampton

Simonne²,

Roka³

et al. 2012

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With increasing environmental concerns, the sharp cost increase of fertilizer and the absence of a soil test to predict nitrogen (N) needs of tomato (Solanum lycopersicon L.) grown on Florida’s sandy soils, a partnership was created with growers, state agencies, and the University of Florida, Institution of Food and Agricultural Sciences (UF/IFAS). The objectives of this study were to identify a range of N rates that would result in highest yields and postharvest quality, and maximum economical return for tomato, grown with subsurface irrigation (management of a perched water table above an impermeable soil layer or hard pan) during the spring season (low probability of leaching rain events). The study was conducted in Spring 2007 and 2008 in Palmetto, FL, with N rates ranging from 22 to 470 kg·ha−1 at pre-plant as ammonium nitrate (NH4NO3). Weather conditions were typical of a dry spring season in central Florida with no leaching rain events recorded in either year; however, rain patterns were different between the 2 years. In the absence of leaching rain and frost protection (either may raise the water table), petiole sap NO3-N decreased over time and the rate of decline depended on the N fertilizer rate. Extra-large and total marketable fruits yields showed a quadratic plateau response to N rates with maximum yields at two harvests (97% of the yields) grown with 172 and 298 kg N/ha in 2007 and 2008, respectively. During subsequent ripening, N rate did not correlate consistently to fruit ripening rate, fruit firmness, nor compositional quality at table-ripe stage. The high value of tomatoes relative to the cost of N fertilizer created a situation in which the profit-maximizing rate of N was not significantly different from the production-maximizing N rate. Whether the profit-maximizing level of N was higher or lower than the UF/IFAS-recommended rate depended on the growing season. With favorable growing conditions (i.e., conditions in 2008), a grower’s net return would have decreased between $1000 and $2000 per hectare by using UF/IFAS-recommended rates depending on market conditions. However, if the UF/IFAS-recommended rate of 224 kg·ha−1 resulted in the highest yield, applying upwards of 300 kg·ha−1 would have increased grower production costs by at least $67/ha. Although fertilizer costs are known before the crop is grown, tomato prices are realized only at the end of the growing season and profit margins can only be calculated after the fact.

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“…Real-time field data could be used as ''BMP intelligence.'' Industry progress in irrigation and nutrient management in the near future is likely to depend on the general economic context (production costs, food safety issues, labor availability) and on educational programs (Simonne and Ozores-Hampton, 2006). The BMP process so far has focused on the land owner and/or on the grower.…”

Section: Potential Role Of Breeding and Grafting On Improving Vegetabmentioning

confidence: 99%

Current Knowledge, Gaps, and Future Needs for Keeping Water and Nutrients in the Root Zone of Vegetables Grown in Florida

Simonne

Hutchinson

DeValerio³

et al. 2010

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The success of the best management practices (BMPs) program for vegetables in Florida is measured by the level of BMP implementation and the improvement of water quality. Both require keeping water and fertilizer in the root zone of vegetables. The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Extension Vegetable Group has identified the fundamental principles of 1) basing UF/IFAS production recommendations on the rigors of science and the reality of field production; 2) replacing the out-of-date paradigm “pollute less by reducing nutrient application rates” with “improve water management and adjust fertilizer programs accordingly”; 3) engaging growers, consultants, educators, and regulators in open-channel discussions; and 4) regularly updating current fertilization and irrigation recommendations for vegetables grown in Florida to reflect current varieties used by the industry. The group identified 1) developing ultralow-flow drip irrigation; 2) assisting conversion from seepage to drip irrigation; 3) using recycled water; 4) developing controlled-release fertilizers for vegetables; 5) developing real-time management tools for continuous monitoring of soil water and chemical parameters; 6) developing yield mapping tools for vegetable crops; 7) developing and testing drainage lysimeter designs suitable for in-field load assessment; and 8) using grafting and breeding to develop commercially acceptable varieties with improved nutrient use efficiency by improving morphological, biochemical, and chemical traits as new strategies to keep nutrients in the root zone. These strategies should become funding priorities for state agencies to help the vegetable industry successfully transition into the BMP era.

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Challenges and Opportunities for Extension Educators Involved in Best Management Practices

Cited by 6 publications

References 11 publications

Effects of Nitrogen Rates on Nitrogen, Phosphorous, and Potassium Partitioning, Accumulation, and Use Efficiency in Seepage-irrigated Fresh Market Tomatoes

Effects of Nitrogen Rates on Nitrogen, Phosphorous, and Potassium Partitioning, Accumulation, and Use Efficiency in Seepage-irrigated Fresh Market Tomatoes

Nitrogen Rates Effects on the Yield, Nutritional Status, Fruit Quality, and Profitability of Tomato Grown in the Spring with Subsurface Irrigation

Current Knowledge, Gaps, and Future Needs for Keeping Water and Nutrients in the Root Zone of Vegetables Grown in Florida

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