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

in HortTechnology

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UF/IFAS production recommendations on the rigors of science and the reality of field production; 2) replacing the out-of-date paradigm “pollute less by reducing nutrient application rates” with “improve water management and adjust fertilizer programs accordingly”; 3) engaging growers,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.

Abstract

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UF/IFAS production recommendations on the rigors of science and the reality of field production; 2) replacing the out-of-date paradigm “pollute less by reducing nutrient application rates” with “improve water management and adjust fertilizer programs accordingly”; 3) engaging growers,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.

Best management practices (BMPs) are cultural practices that aim at improving the quality of Florida waters while maintaining or improving productivity [Florida Department of Agriculture and Consumer Services (FDACS), 2005]. Because water is the carrier of soluble nutrients and sediments, the overall goal of BMP implementation is to keep water and nutrients in the root zones of vegetables. This report 1) describes the typical nutrient management systems used in Florida for vegetable crop production; 2) compiles known estimates of nutrient load; 3) discusses the feasibility of zero-discharge systems for vegetables; 4) assesses the potential role of breeding and grafting on improving vegetable crop nutrient use efficiency; and 5) develops a vision on what the Florida vegetable industry at large could do to improve water quality. The state agencies involved in BMP in Florida are FDACS, the Florida Department of Environmental Protection, the five water management districts of Florida, and the University of Florida Institute of Food and Agricultural Sciences. These agencies may find these topics useful in planning and coordinating funding allocation, identifying future research needs, and supporting educational programs.

Current nutrient and water management practices used by Florida producers

Vegetables are grown on three main types of soils (sandy, organic, and calcareous soils) using three main types of irrigation methods (overhead, drip, and/or seepage irrigation), two main types of production systems (bare ground or mulched crop), and three seasons (fall, winter, and spring). This diversity creates a wide array of production systems over varying weather conditions, each having its own requirements for water and nutrient management. These systems were recently reviewed in a white paper published by the UF/IFAS Vegetable Fertilizer Task Force (Cantliffe et al., 2006). Production recommendations support the use of on-farm weather data, soil tests, soil moisture-sensing devices (mostly for drip- and overhead-irrigated crops), water table monitoring tools (for seepage-irrigated crops), whole-leaf analysis, and/or petiole sap tests to schedule irrigation and monitor crop nutrition. Success stories on how these tools have helped improve on-farm water and nutrient management have been reported with muskmelon (Cucumis melo) and watermelon (Citrullus lanatus) (Simonne et al., 2005) and strawberry [Fragaria ×ananassa (Hochmuth et al., 2003c)].

article image

Crop-by-crop fertilizer recommendations for vegetables grown on sandy soils may be found in the Vegetable Production Handbook for Florida (Olson and Simonne, 2007). UF/IFAS fertilizer recommendations include a base fertilizer rate and a supplemental application allowed after a leaching rain (defined as 3 inches of rainfall in 3 d or 4 inches in 7 d), an extended harvest season, and/or when plant nutritional status is diagnosed as “low” based on whole leaf analysis or petiole sap testing. Recommendations also include fertilizer placement (banded, broadcast, or modified broadcast), fertilizer sources when necessary, preplant fertilizer application amounts, and fertigation schedules. These fertilizer recommendations, based on research from the 1980s and 1990s, propose a single nitrogen (N) rate for all irrigation systems, production seasons, and Florida soil types (Olson and Simonne, 2007). Recommendations for phosphorus (P), potassium, calcium, magnesium, and micronutrient applications on sandy soils are based on Mehlich 1 soil test results. Recommendations for vegetable crops grown on muck soils are available (Hochmuth et al., 2003a, 2003b). Fertilizer recommendations for vegetable crops grown on the calcareous soils of southern Miami–Dade County are currently incomplete because no calibrated soil test is available for the area (Li et al., 2006a, 2006b, 2006c, 2006d, 2006e, 2006f, 2006g, 2006h, 2006i, 2006j). In the absence of a calibrated soil test for this Florida soil type (ammonium bicarbonate–diethylene triamine penta-acetic acid extractant has been considered), fertilizer recommendations and, hence, practices are based on experience and results of whole leaf analysis and/or petiole sap testing.

UF/IFAS irrigation scheduling recommendations for vegetable crops grown with seepage irrigation are to maintain the water table at the 15- to 31-cm depth when plants are small and at the 31- to 61-cm depth when plants are fully grown. Irrigation recommendations for vegetables grown with overhead and drip irrigation include to 1) use an evapotranspiration (ET) -based target volume; 2) fine-tune volume based on soil moisture level; 3) split irrigation to limit water movement below the root zone; and 4) keep records of irrigation practices (Simonne et al., 2007). As recommended by the UF/IFAS Vegetable Fertilizer Task Force, research results on fertilizer and irrigation management developed in the context of the BMP and published in refereed journal articles since the early 2000s need to be incorporated into UF/IFAS recommendations (Cantliffe et al., 2006). Recently approved updates to UF/IFAS fertilization recommendations from the UF/IFAS Vegetable Fertilizer Task Force were to 1) adopt preliminary N recommendations for drip-irrigated grape tomato (Solanum lycopersicum var. cerasiforme); 2) report lack of efficacy of foliar-applied calcium sprays to improve strawberry yields and postharvest quality; and 3) increase by 25% N fertilization recommendation for seepage-irrigated crops to compensate for denitrification losses (UF/IFAS Plant Nutrient Oversight Committee, unpublished data).

Current methods for load measurement and available estimates

Quantifying nutrient load from vegetable production systems is the first step toward monitoring groundwater pollution in the field and understanding how each group of BMP contributes to load reduction. A nutrient load is defined as the weight of a chemical entering or leaving an area, and it is calculated as the product of the volume of water that the chemical is transported in and the concentration of the chemical in the water (Rice and Izuno, 2001). Past research has focused mostly on improving estimation of nutrient concentration, and several assumptions are often made in determining the corresponding volume of water on a per-acre basis. This is important for vegetable crops grown on raised beds because the leaching or wetted surface depends on bed compaction, width, and spacing (Farneselli et al., 2008). Load estimates may vary from simple to double based on the assumptions made on the size and shape of the wetted zone (Farneselli et al., 2008). Because nutrient concentration and size/shape of the wetted zone are equally important for in-field load determinations, they should be estimated with the same level of accuracy.

Nutrient load can be determined indirectly or directly. The indirect approaches of measuring load include nutrient flow models and nutrient balances. Nutrient flow models are important tools for evaluating the impact of nutrient leaching on water quality at the watershed level and play an important role in designing agricultural and environmental policies. Direct methods for calculating load at the field level are resin traps, soil sampling, or drainage lysimeters (Farneselli et al., 2008; Pampolino et al., 2000; Zotarelli et al., 2007). Although each of these methods has its own advantages and limits, small, in-row drainage lysimeters are emerging as a practical tool for direct load measurements (Gazula et al., 2006; Migliaccio et al., 2006; Zotarelli et al., 2008). A partial vacuum may be added to low-cost drainage lysimeters to prevent water logging without compromising the accuracy of the results (Evett et al., 2006). At 0.0013 mm, accuracy of drainage measurement was nearly two orders of magnitude better than that of the lysimeter weight measurement (1 mm), ensuring that the continuous drainage measurement may be included in the weight balances determination of ET without diminishing the accuracy of ET values (Evett et al., 2006).

Few in-field load estimates have been published for vegetables, and few of those were developed on sandy soils applicable to Florida (Table 1). Load estimates ranged from 1 to 400 kg·ha−1 of N and varied based on crops, cultural practices, and irrigation/fertilizer management, but also based on the methodology used for extrapolating load calculations to a per-hectare basis. Hence, efforts should be made to standardize protocols and methodology for in-field load estimation. In addition, the link between irrigation management and nutrient leaching shows that education on irrigation and nutrient management is central to BMP implementation. In-field load assessment should be considered a funding priority by state agencies. An increased fertilizer rate does not directly translate into an increase in load. This first requires the development of reliable methods and tools of known precision because watershed-level load simulations are poor indicators of actual field-level leaching. The effect of all fertilizer recommendations on nutrient load should be determined for all major vegetable crops through on-farm research projects in regionally appropriate production areas.

Table 1.

Published estimates of nitrogen (N) load for selected crops.

Table 1.

Zero-discharge systems

Achieving zero-discharge systems would ensure that water is kept in the root zone of vegetables. In theory, spodosols allow for a natural zero-discharge system when the spodic layer is continuous and in the absence of rain. In short, spodosols have an impermeable layer that transforms a field into a giant bathtub. When it rains, water needs to be pumped out of the field to prevent flooding. Currently, a zero-discharge system on deep sand soils does not seem technically feasible in field production (past attempts to create physical barriers of concrete or plastic have failed). By contrast, it can be done relatively simply in greenhouse production. Attempts to modify soil water-holding capacity in open fields by using organic (compost, modified corn starch, polyacrylamides) or inorganic (zeolites) amendments are economically and technically not feasible as a result of the large quantities of material needed (Bhardwaj et al., 2007; Sepaskhah and Yousefi, 2007; Sivapalan, 2006; Vachere et al., 2003).

Cover crops are often presented as an underused BMP. Cover crops may be used to compete with weeds (Linares et al., 2008), return biomass and nutrients to the soil (Muñoz-Arboleda et al., 2008; Schomberg et al., 2007), and retain pesticide residues (Potter et al., 2007). However, cover crops are not used as often as expected because more research is needed to 1) identify suitable cover crops for different seasons in Florida; 2) assess the role of a cover crop in the life cycle of crop pests (disease, insect, and virus); and 3) quantify the real capability of nutrient scavenging of each cover crop. Cost and seed availability are also cited as impediments to a broader use of cover crops. Hence, as a result of the low water-holding capacity of Florida sandy soils and unpredictable rainfall patterns, zero discharge in field production should be considered a reachable goal, but in the long term, “quasi-zero discharge” may be more realistic.

Catch ponds are sometimes used to collect excess rainfall in seepage-irrigated systems. However, ponds represent a large capital investment and permanently occupy land. The use of polyacrylamide blocks or zeolite filters located at key structures/discharge points have shown promise to trap soluble nutrients and sediments in arid environments (Zreig et al., 2007). Limited research has been conducted so far by UF/IFAS on this topic, but engineering firms have successfully used this technology on construction sites throughout Florida. However, peak volumes during storm events may be excessively large on commercial operations, thereby limiting this practice. Zero-discharge systems in mulched and drip-irrigated fields with deep sandy soils may be approachable if drip irrigation application rates can match hourly crop ET rates. This will require slight modification of existing systems (filters and pipes) and the development of ultralow-flow drippers.

Controlled-release fertilizers [CRFs (mostly for N)] should also be part of the zero-discharge approach. Currently, limited information is available on the use of CRFs for vegetables, except potato [Solanum tuberosum (Hutchinson, 2004; Pack et al., 2006; Simonne and Hutchinson, 2005)]. An ongoing project is assessing seepage-irrigated tomato and bell pepper (Capsicum annuum) responses to CRFs in southern Florida. Research on developing CRF-based fertilization programs should be supported for all the main crops grown with seepage irrigation, including potato, tomato, bell pepper, eggplant (Solanum melongena), watermelon, and cabbage (Brassica oleracea var. capitata).

Potential role of breeding and grafting on improving vegetable crop nutrient use efficiency

Together with adjustment in cultural practices, load reduction may be accomplished by using varieties selected for improved nutrient uptake characteristics. Most public breeding programs focus on developing parents for hybrids, whereas private breeding programs mostly produce industry-ready varieties. With the exception of N-efficient potato varieties from Europe, improved nutrient use efficiency (NUE) is rarely the main focus of either type of vegetable breeding programs. Overall, breeding for improved pest resistance is the main focus. By using high fertility rates in breeding programs, little emphasis is placed on “passively” selecting for high NUE varieties. Hence, public and private breeding programs will have to be committed to NUE in the parents and new commercial varieties released.

Efforts to improve NUE have been conducted in the last 40 years on food crops of worldwide importance such as wheat [Tricticum aestivum (Abad et al., 2004; Chao et al., 2007)], corn [Zea mays (Halvorson et al., 2002)], and bean [Phaseolus vulgaris (Beebe et al., 2006)] with emphasis on horticultural productivity and nutritional quality of the harvested plant part. Differences in nutrient uptake patterns among genotypes within a genus are known for many vegetable crops, including tomato (JianJun and Gabelman, 1995; O'Sullivan et al., 1974), cabbage (JinKiu et al., 2006; Tanaka and Sato, 1997), potato (Shahnazari et al., 2008; Sharifi and Zebarth, 2006; Sharifi et al., 2007), and pumpkin [Cucurbita pepo (Swiader et al., 1994)]. However, the focus of these research projects was mostly to document phenotypical differences or to improve the adaptation of current lines to areas of poor growing conditions (such as salinity or micronutrient deficiencies) rather than identify genes involved in nutrient uptake. Breeding approaches that may increase plant nutrient use efficiency include 1) anatomical modifications of root system architecture, including increased branching and number of small, absorbing roots (Beebe et al., 2006; Frith and Nichols, 1975; Muñoz-Arboleda et al., 2006; XiangRong et al., 2005); 2) chemical modification of the soil around the roots that increase the availability of nutrients [release of phosphatases that make P more available (George et al., 2005) or citrate that lower and buffer the pH near the roots (Schenk, 2006)]; 3) biochemical modification of the root surface by increasing the number of absorption sites on each root (Cuartero and Fernandez-Muñoz, 1999); and 4) understanding the regulation of genes involved in nutrient uptake (Chao et al., 2007).

With all the plant physiology knowledge developed since the 1970s and the recent progress in genomics, breeding for root systems with improved NUE may soon become a reality. It will require the commitment of UF/IFAS breeding programs and the identification of all the genes that code for the phenotype of interest. Projects should link together soil chemistry, plant biochemistry, plant physiology, and genomics. Although this type of effort may contribute to BMP adoption and improvement of water quality, the full funding of these long-term, basic projects may be beyond the scope of funding by the Florida agencies involved in the BMP program. However, these agencies could partially support these projects.

Traditionally, breeding has focused on improving the genotype of a single (open-pollinated) or two (hybrid) parents. Vegetable grafting is an innovative technique successfully practiced in Asia, parts of Europe, and the Middle East that develops a new plant by physically uniting two plants (the rootstock and the scion) through the graft (Edelstein, 2004; Lee, 2007). Resistant rootstocks, grafting methods, and procedures are being developed primarily on tomato, eggplant, and watermelon for the management of soilborne pathogens such as fusarium, verticillium, and nematodes. In addition to disease control, grafted plants have shown tolerance to environmental stresses such as low temperature and salinity (Estañ et al., 2005; Lee, 1994). Because grafted vegetables often exhibit significant yield increases as a result of vigorous growth even in the absence of disease pressure, it is possible that grafting may enhance water and nutrient uptake by plants (Khah et al., 2006; Lee, 1994; Qaryouti et al., 2007). Hence, grafting may help speed the development of nutrient- and water-efficient plants. If the commercial plant material targeted is a grafted transplant, a novel approach to plant breeding could be to separately develop hybrid rootstocks and hybrid scions. Economical analysis will have to establish the breakeven point between the environmental benefit and the cost of labor and seed associated with grafting before this technique is adopted by the industry.

Vision for the next 5 years: What does the industry need to do better?

The main technically feasible practices that could be implemented or developed in the short term include 1) switching from seepage to drip irrigation; 2) identifying adequate release pattern from CRFs for seepage-irrigated crops; and 3) developing ultralow-flow drip tapes for drip irrigation (Tables 2, 3, and 4). In theory, keeping the water in the root zone of vegetable crops could be achieved by having an adjustable flow-rate emitter (by changing operating pressure) in which flow rate could match hourly crop ET. The feasibility of achieving ultralow-flow rates (1.02 to 1.53 L·m−1·h−1) by operating current emitters at lower pressures or developing new emitters needs to be investigated. This may require the development of partnerships with irrigation supply manufacturers. Also, the effects of low pressure on uniformity and filtration requirements need to be addressed to reduce clogging risk. We believe that ultralow-flow drip irrigation is the strategy that has the greatest potential to simultaneously keep the water in the root zone of vegetable crops and reduce water use (another challenge in Florida, but not directly tied with the BMP program). The economical feasibility of implementation of each of these practices also needs to be determined. In addition, 4) real-time, continuous sensing of soil moisture status, soil EC, and nutrient concentrations; and 5) yield mapping as a basis for nutrient application and using recycled water need to be considered. In doing so, fertilizer and irrigation management needs to be considered within a production system (and not as independent variables that can be changed as needed) and the cost of each new technique needs to be related with the value of the information provided to the grower. The development of new soil nutrient sensors and yield mapping techniques offers the attractive prospective of reducing the need for soil sampling and of linking field heterogeneity to nutrient management. Real-time field data could be used as “BMP intelligence.”

Table 2.

Summary of current best management practice (BMP) research areas for vegetables grown in Florida, level of knowledge, and gaps.

Table 2.
Table 3.

Questions to and summary of vision statements by key University of Florida Institute of Food and Agricultural Science (UF/IFAS) state and county faculty with active programs in best management practices (BMP) for vegetable crops.

Table 3.
Table 4.

Strategic areas of future research for improving the quality of Florida waters, their respective approaches, and estimated chances of success.

Table 4.

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. However, the commitment of the consulting and fertilizer industry to the BMP program and water quality also needs to be strengthened. Similar to what was developed for pesticides in the 1970s, a fertilizer applicator's license program coordinated by FDACS and educationally supported by UF/IFAS should be developed based on the existing Certified Crop Advisor program. In a state like Florida where UF/IFAS is not the sole direct source of information for the growers, it is essential that all segments of the vegetable industry be involved in the BMP program.

The mobile irrigation laboratories, the BMP implementation teams, and local extension offices should be supported and given the resources necessary to fully use their knowledge, experience, credibility, and connection with the growers to ensure a rapid adoption of BMP by the vegetable industry in Florida.

Literature cited

  • AbadA.LloverasJ.MichelenaA.2004Nitrogen fertilization and foliar urea effects on durum wheat yield and quality and on residual soil nitrate in irrigated Mediterranean conditionsField Crops Res.87257269

    • Search Google Scholar
    • Export Citation
  • Allaire-LeungS.E.WuL.MitchellJ.P.SandenB.L.2001Nitrate leaching and soil nitrate content as affected by irrigation uniformity in a carrot fieldAgr. Water Mgt.483750

    • Search Google Scholar
    • Export Citation
  • AparicioV.CostaJ.L.ZamoraM.2008Nitrate leaching assessment in a long-term experiment under supplementary irrigation in humid ArgentinaAgr. Water Mgt.9513611372

    • Search Google Scholar
    • Export Citation
  • BeebeS.E.Rojas-PierceM.XioaLongY.BlairM.W.PedrazaF.MunozF.TohmeJ.LynchJ.P.2006Quantitative trait loci for root architecture traits correlated with phosphorus acquisition in common beanCrop Sci.46413423

    • Search Google Scholar
    • Export Citation
  • BhardwajA.K.ShainbergI.GoldsteinD.WarringtonD.N.LevyG.J.2007Water retention and hydraulic conductivity of cross-linked polyacrylamides in sandy soilsSoil Sci. Soc. Amer. J.71406412

    • Search Google Scholar
    • Export Citation
  • CantliffeD.GilreathP.HamanD.HutchinsonC.LiY.McAvoyG.MigliaccioK.OlczykT.OlsonS.ParmenterD.SantosB.ShuklaS.SimonneE.StanleyC.WhiddenA.2006Review of nutrient management systems for Florida vegetable producersProc. Florida State Hort. Soc.119240248

    • Search Google Scholar
    • Export Citation
  • ChaoC.XueQiangZ.YongGuanZ.BinL.YiPingT.ZhenShengL.2007Regulation of the high-affinity nitrate transport system in wheat roots by exogenous abscisic acid and glutamineJ. Integr. Plant Biol.4917191725

    • Search Google Scholar
    • Export Citation
  • CuarteroJ.Fernandez-MuñozR.1999Tomato and salinityScientia Hort.7883125

  • DaudénA.QuílezD.2004Pig slurry versus mineral fertilization on corn yield and nitrate leaching in a Mediterranean irrigated environmentEur. J. Agron.21719

    • Search Google Scholar
    • Export Citation
  • EdelsteinM.2004Grafting vegetable-crop plants: Pros and consActa Hort.659235238

  • EstañM.T.Martinez-RodriguezM.M.Perez-AlfoceaF.FlowersT.J.BolarinM.C.2005Grafting raises the salt tolerance of tomato through limiting the transport of sodium and chloride to the shootJ. Expt. Bot.56703712

    • Search Google Scholar
    • Export Citation
  • EvettS.R.RuthardtB.B.CopelandK.S.2006External full-time vacuum lysimeter drainage systemAppl. Eng. Agr.22875880

  • FarneselliM.StudstillD.W.SimonneE.H.HochmuthR.C.HochmuthG.J.TeiF.2008Depth and width of the wetted zone after leaching irrigation on a sandy soil and implication for nitrate load calculationCommun. Soil Sci. Plant Anal.3911831192

    • Search Google Scholar
    • Export Citation
  • Florida Department of Agriculture and Consumer Services2005Water quality/quantity best management practices for Florida vegetable and agronomic crops15 Mar. 2008<http://www.floridaagwaterpolicy.com/PDF/Bmps/Bmp_VeggieAgroCrops2005.pdf>.

    • Export Citation
  • FrithG.J.T.NicholsD.G.1975Effects of nitrogen fertilizer applications to part of a root systemBritish Columbia Orchardist1510

  • GazulaA.SimonneE.DukesM.HochmuthG.HochmuthB.StudstillD.2006Optimization of drainage lysimeter design for field determination of nitrogen loadsProc. Florida State Hort. Soc.119213233

    • Search Google Scholar
    • Export Citation
  • GeorgeT.S.RichardsonA.E.SmithJ.B.HadobasP.A.SimpsonR.J.2005Limitations to the potential of transgenic Trifolium subterraneum L. plants that exude phytase when grown in soils with a range of organic P contentPlant Soil278262274

    • Search Google Scholar
    • Export Citation
  • HalvorsonA.D.FollettR.F.BartoloM.E.SchweissingF.C.2002Nitrogen fertilizer use efficiency of furrow-irrigated onion and cornAgron. J.94442449

    • Search Google Scholar
    • Export Citation
  • HochmuthG.J.HanlonE.NagataR.SnyderG.SchuenemanT.2003aFertilization recommendations of crisphead lettuce grown on organic soils in Florida15 Mar. 2008<http://edis.ifas.ufl.edu/WQ114>.

    • Export Citation
  • HochmuthG.J.HanlonE.NagataR.SnyderG.SchuenemanT.2003bFertilization of sweet corn, celery, romaine, escarole, endive, and radish on organic soils in FloridaUniv. Florida, Inst. Food Agr. Sci., Bul. 31315 Mar. 2008<http://edis.ifas.ufl.edu/CV008>.

    • Export Citation
  • HochmuthR.DinkinD.SweatM.SimonneE.2003cExtension programs in northeastern Florida help growers produce quality strawberries by improving water and nutrient managementUniv. Florida, Inst. Food Agr. Sci., HS 95615 Mar. 2008<http://edis.ifas.ufl.edu/HS190>.

    • Export Citation
  • HutchinsonC.M.2004Influence of a controlled release nitrogen fertilizer program on potato (Solanum tuberosum L.) tuber yield and qualityActa Hort.68499102

    • Search Google Scholar
    • Export Citation
  • JianJunC.GabelmanW.H.1995Isolation of tomato stains varying in potassium acquisition using a sand-zeolite culture systemPlant Soil1766570

    • Search Google Scholar
    • Export Citation
  • JinKiuL.ShuBinS.LiJinJ.WeiC.QiRongS.2006The mechanism of nitrate accumulation in pakchoi [Brassica campestris L ssp.chinensis (L.)]Plant Soil282291300

    • Search Google Scholar
    • Export Citation
  • KhahE.M.KakavaE.MavromatisA.ChachalisD.GoulasC.2006Effect of grafting on growth and yield of tomato (Lycopersicon esculentum Mill.) in greenhouse and open-fieldJ. Appl. Hort.837

    • Search Google Scholar
    • Export Citation
  • LecompteF.BressoudF.ParesL.De BruyneF.2008Root and nitrate distribution as related to the critical plant N status of a fertigated tomato cropJ. Hortic. Sci. Biotechnol.83223231

    • Search Google Scholar
    • Export Citation
  • LeeJ.M.1994Cultivation of grafted vegetables. I. Current status, grafting methods, and benefitsHortScience29235239

  • LeeS.G.2007Production of high quality vegetable seedling graftsActa Hort.759169174

  • LiY.C.KlassenW.LambertsM.OlczykT.2006aBush and pole bean production in Miam–Dade County, Florida15 Mar. 2008<http://edis.ifas.ufl.edu/TR005>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006bCabbage production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85415 Mar. 2008<http://edis.ifas.ufl.edu/TR006>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006cCucumber production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85515 Mar. 2008<http://edis.ifas.ufl.edu/TR007>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006dEggplant production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85615 Mar. 2008<http://edis.ifas.ufl.edu/TR008>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006eOkra production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85715 Mar. 2008<http://edis.ifas.ufl.edu/TR009>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006fPepper production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85915 Mar. 2008<http://edis.ifas.ufl.edu/TR010>.

    • Export Citation
  • LiY.C.KlassenW.O'HairS.LambertsM.OlczykT.2006gPotato production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 86015 Mar. 2008<http://edis.ifas.ufl.edu/TR011>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006hSummer squash production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 86115 Mar. 2008<http://edis.ifas.ufl.edu/TR012>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006iSweet corn production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 86215 Mar. 2008<http://edis.ifas.ufl.edu/TR013>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006jTomato production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85815 Mar. 2008<http://edis.ifas.ufl.edu/TR014>.

    • Export Citation
  • LinaresJ.ScholbergJ.BooteK.ChaseC.A.FergusonJ.J.McSorleyR.2008Use of the crop weed index to evaluate weed suppression by cover crops in organic citrus orchardsHortScience432734

    • Search Google Scholar
    • Export Citation
  • MacaigneP.ParentL.E.AnctilF.2008Single-hole soil sampling for nitrogen in the potato hillCommun. Soil Sci. Plant Anal.3914861492

  • MigliaccioK.W.YuncongL.TraffordH.EvansE.2006A simple lysimeter for soil water sampling in south FloridaUniv. Florida, Inst. Food Agr. Sci., Circ. ABE 36115 Mar. 2008<http://edis.ifas.ufl.edu/AE387>.

    • Export Citation
  • Muñoz-ArboledaF.MylavarapuR.HutchinsonC.2006Root distribution under seepage-irrigated potatoes in northeast FloridaAmer. J. Potato Res.83463472

    • Search Google Scholar
    • Export Citation
  • Muñoz-ArboledaF.MylavarapuR.HutchinsonC.PortierK.2008Nitrate-nitrogen concentrations in the perched ground water under seepage-irrigated potato cropping systemsJ. Environ. Qual.37387394

    • Search Google Scholar
    • Export Citation
  • O'SullivanJ.GabelmanW.H.GerloffG.C.1974Variations in efficiency of nitrogen utilization in tomatoes (Lycopersicon esculentum Mill.) grown under nitrogen stressJ. Amer. Soc. Hort. Sci.99543547

    • Search Google Scholar
    • Export Citation
  • OikehS.O.CarskyR.J.KlingJ.G.ChudeV.O.HorstW.J.2003Differential N uptake by maize cultivars and soil nitrate dynamics under N fertilization in West AfricaAgr. Ecosyst. Environ.100181191

    • Search Google Scholar
    • Export Citation
  • OlsonS.M.SimonneE.H.2007Vegetable production handbook for Florida 2007–2008Vance PublishingLenexa, KS

    • Export Citation
  • PackJ.E.HutchinsonC.M.SimonneE.H.2006Evaluation of controlled-release fertilizers for northeast Florida chip potato productionJ. Plant Nutr.2913011313

    • Search Google Scholar
    • Export Citation
  • PampolinoM.F.UrushiyamaT.HatanoR.2000Detection of nitrate leaching through bypass flow using pan lysimeter, suction cup, and resin capsuleSoil Sci. Plant Nutr.46703711

    • Search Google Scholar
    • Export Citation
  • PaudelK.P.AdhikariM.MartinN.R.Jr2004Evaluation of broiler litter transportation in northern Alabama, USAJ. Environ. Manage.731523

  • PeraltaJ.M.StockleC.O.2002Dynamics of nitrate leaching under irrigated potato rotation in Washington State: A long-term simulation studyAgric. Ecosyst. Environ.882334

    • Search Google Scholar
    • Export Citation
  • PotterT.L.BoschD.D.JooH.SchafferB.Muñoz-CarpenaR.2007Summer cover crops reduce atrazine leaching to shallow groundwater in Southern FloridaJ. Environ. Qual.3613011309

    • Search Google Scholar
    • Export Citation
  • QaryoutiM.M.QawasmiW.HamdanH.EdwanM.2007Tomato fruit yield and quality as affected by grafting and growing systemActa Hort.741199206

    • Search Google Scholar
    • Export Citation
  • RajputT.B.S.PatelN.2006Water and nitrate movement in drip-irrigated onion under fertigation and irrigation treatmentsAgr. Water Mgt.79293311

    • Search Google Scholar
    • Export Citation
  • RamosC.AgutA.LidónA.L.2002Nitrate leaching in important crops of the Valencian Community region (Spain)Environ. Pollut.118215223

  • RiceR.W.IzunoF.T.2001Calculating nutrient loadsUniv. Florida, Inst. Food Agr. Sci., Res. Tech. Bul. 90615 Mar. 2008<http://edis.ifas.ufl.edu/AE149>.

    • Export Citation
  • RomicD.RomicM.BorosicJ.PoljakM.2003Mulching decreases nitrate leaching in bell pepper (Capsicum annuum L.) cultivationAgr. Water Mgt.608797

    • Search Google Scholar
    • Export Citation
  • SainjuU.M.SinghB.P.RahmanS.ReddyV.R.1999Soil nitrate–nitrogen under tomato following tillage, cover cropping, and nitrogen fertilizationJ. Environ. Qual.2818371844

    • Search Google Scholar
    • Export Citation
  • SchenkM.K.2006Nutrient efficiency in vegetable cropsActa Hort.7002123

  • SchombergH.H.MartiniN.L.Diaz-PerezJ.C.PhatakS.C.BalkomK.S.BhardwajH.L.2007Potential for using sun hemp as a source of biomass and nitrogen for the piedmont and coastal plain regions of the southeastern USAAgron. J.9914481457

    • Search Google Scholar
    • Export Citation
  • SepaskhahA.R.YousefiF.2007Effect of zeolite application on nitrate and ammonium retention of a loamy soil under saturated conditionsAust. J. Soil Res.45368373

    • Search Google Scholar
    • Export Citation
  • ShahnazariA.AhmadiS.H.LaerkeP.E.FuLaiL.PlauborgF.JacobsenS.E.JensenC.R.AndersenM.N.2008Nitrogen dynamics in the soil-plant system under deficit and partial root-zone drying irrigation strategies in potatoesEur. J. Agron.286573

    • Search Google Scholar
    • Export Citation
  • SharifiM.ZebarthB.J.2006Nitrate influx kinetic parameters of five potato cultivars during vegetative growthPlant Soil2289199

  • SharifiM.ZebarthB.J.ColemanW.2007Screening for nitrogen-use efficiency in potato with a recirculating hydroponic systemCommun. Plant Sci. Soil Anal.38359370

    • Search Google Scholar
    • Export Citation
  • SimonneE.H.DukesM.D.HamanD.Z.2007Principles and practices for irrigation managementUniv. Florida, Inst. Food Agr. Sci., AE26015 Mar. 2008<http://edis.ifas.ufl.edu/CV107>.

    • Export Citation
  • SimonneE.H.HutchinsonC.M.2005Controlled release fertilizer for vegetable crops: Teaching new tricks to an old dogHortTechnology151424

  • SimonneE.H.Ozores-HamptonM.2006Challenges and opportunities for extension educators involved in best management practicesHortTechnology16403407

    • Search Google Scholar
    • Export Citation
  • SimonneE.H.StudstillD.W.HochmuthR.C.JonesJ.T.StarlingC.W.2005On-farm demonstration of soil water movement in vegetables grown with plasticultureUniv. Florida, Inst. Food Agr. Sci., HS 100815 Mar. 2008<http://edis.ifas.ufl.edu/HS251>.

    • Export Citation
  • SivapalanS.2006Benefits of treating a sandy soil with a crosslinked-type polyacrylamideAust. J. Exp. Agr.46579584

  • StockleC.O.MartinS.A.CampbellG.S.1994CropSyst, a cropping systems simulation model: Water/nitrogen budgets and crop yieldAgr. Syst.46335359

    • Search Google Scholar
    • Export Citation
  • SwiaderJ.M.ChvanY.FreijiF.G.1994Genotypic differences in nitrate uptake and utilization efficiency in pumpkin hybridsJ. Plant Nutr.1716871699

    • Search Google Scholar
    • Export Citation
  • SyvertsenJ.P.JifonJ.L.2001Frequent fertigation does not affect citrus tree growth, fruit yield, nitrogen uptake, and leaching lossesProc. Florida State Hort. Soc.1148893

    • Search Google Scholar
    • Export Citation
  • TanakaT.SatoT.1997Growth and nutrient absorption characteristics of three commercial cabbage cultivars under varying nitrogen levelsJpn. J. Soil Sci. Plant Nutr.68493500

    • Search Google Scholar
    • Export Citation
  • VachereC.A.LochR.J.RaineS.R.2003Effect of polyacrylamide additions on infiltration and erosion of disturbed landsAust. J. Soil Res.4115091520

    • Search Google Scholar
    • Export Citation
  • VázquezN.PardoaA.SusoaM.L.QuemadabM.2006Drainage and nitrate leaching under processing tomato growth with drip irrigation and plastic mulchingAgr. Ecosyst. Environ.112313323

    • Search Google Scholar
    • Export Citation
  • XiangRongW.ZhengQuanW.YouZhiH.JianCunG.DaLiG.LiM.2005Variations of fine root diameter with root order in manchurian ash and duhurian larch plantationsActa Phytoecol. Sin.29871877

    • Search Google Scholar
    • Export Citation
  • YaffaS.SainjuU.M.SinghB.P.2000Fresh market tomato yield and soil nitrogen as affected by tillage, cover cropping, and nitrogen fertilizationHortScience3512581262

    • Search Google Scholar
    • Export Citation
  • ZhuJ.H.LiX.L.ChristieP.LiJ.L.2005Environmental implications of low nitrogen use efficiency in excessively fertilized hot pepper (Capsicum frutescens L.) cropping systemsAgric. Ecosyst. Environ.1117080

    • Search Google Scholar
    • Export Citation
  • ZotarelliL.DukesM.D.ScholbergJ.M.HanselmanT.FemminellaK.L.Muñoz-CarpenaR.2008Nitrogen and water use efficiency of zucchini squash for a plastic mulch bed system on a sandy soilScientia Hort.116816

    • Search Google Scholar
    • Export Citation
  • ZotarelliL.ScholbergJ.M.DukesM.D.Muñoz-CarpenaR.2007Monitoring of nitrate leaching in sandy soils: Comparison of three methodsJ. Environ. Qual.36953962

    • Search Google Scholar
    • Export Citation
  • ZreigA.SharifA.AmayrehJ.2007Erosion control of arid land in Jordan with two anionic polyacrylamidesArid Land Res. Manage.21315328

  • ZvomuyaF.RosenC.J.RusselleM.P.GuptaS.C.2003Nitrate leaching and nitrogen recovery following application of polyolefin-coated urea to potatoJ. Environ. Qual.32480489

    • Search Google Scholar
    • Export Citation

If the inline PDF is not rendering correctly, you can download the PDF file here.

Contributor Notes

Corresponding author. E-mail: esimonne@ufl.edu.

Article Sections

Article References

  • AbadA.LloverasJ.MichelenaA.2004Nitrogen fertilization and foliar urea effects on durum wheat yield and quality and on residual soil nitrate in irrigated Mediterranean conditionsField Crops Res.87257269

    • Search Google Scholar
    • Export Citation
  • Allaire-LeungS.E.WuL.MitchellJ.P.SandenB.L.2001Nitrate leaching and soil nitrate content as affected by irrigation uniformity in a carrot fieldAgr. Water Mgt.483750

    • Search Google Scholar
    • Export Citation
  • AparicioV.CostaJ.L.ZamoraM.2008Nitrate leaching assessment in a long-term experiment under supplementary irrigation in humid ArgentinaAgr. Water Mgt.9513611372

    • Search Google Scholar
    • Export Citation
  • BeebeS.E.Rojas-PierceM.XioaLongY.BlairM.W.PedrazaF.MunozF.TohmeJ.LynchJ.P.2006Quantitative trait loci for root architecture traits correlated with phosphorus acquisition in common beanCrop Sci.46413423

    • Search Google Scholar
    • Export Citation
  • BhardwajA.K.ShainbergI.GoldsteinD.WarringtonD.N.LevyG.J.2007Water retention and hydraulic conductivity of cross-linked polyacrylamides in sandy soilsSoil Sci. Soc. Amer. J.71406412

    • Search Google Scholar
    • Export Citation
  • CantliffeD.GilreathP.HamanD.HutchinsonC.LiY.McAvoyG.MigliaccioK.OlczykT.OlsonS.ParmenterD.SantosB.ShuklaS.SimonneE.StanleyC.WhiddenA.2006Review of nutrient management systems for Florida vegetable producersProc. Florida State Hort. Soc.119240248

    • Search Google Scholar
    • Export Citation
  • ChaoC.XueQiangZ.YongGuanZ.BinL.YiPingT.ZhenShengL.2007Regulation of the high-affinity nitrate transport system in wheat roots by exogenous abscisic acid and glutamineJ. Integr. Plant Biol.4917191725

    • Search Google Scholar
    • Export Citation
  • CuarteroJ.Fernandez-MuñozR.1999Tomato and salinityScientia Hort.7883125

  • DaudénA.QuílezD.2004Pig slurry versus mineral fertilization on corn yield and nitrate leaching in a Mediterranean irrigated environmentEur. J. Agron.21719

    • Search Google Scholar
    • Export Citation
  • EdelsteinM.2004Grafting vegetable-crop plants: Pros and consActa Hort.659235238

  • EstañM.T.Martinez-RodriguezM.M.Perez-AlfoceaF.FlowersT.J.BolarinM.C.2005Grafting raises the salt tolerance of tomato through limiting the transport of sodium and chloride to the shootJ. Expt. Bot.56703712

    • Search Google Scholar
    • Export Citation
  • EvettS.R.RuthardtB.B.CopelandK.S.2006External full-time vacuum lysimeter drainage systemAppl. Eng. Agr.22875880

  • FarneselliM.StudstillD.W.SimonneE.H.HochmuthR.C.HochmuthG.J.TeiF.2008Depth and width of the wetted zone after leaching irrigation on a sandy soil and implication for nitrate load calculationCommun. Soil Sci. Plant Anal.3911831192

    • Search Google Scholar
    • Export Citation
  • Florida Department of Agriculture and Consumer Services2005Water quality/quantity best management practices for Florida vegetable and agronomic crops15 Mar. 2008<http://www.floridaagwaterpolicy.com/PDF/Bmps/Bmp_VeggieAgroCrops2005.pdf>.

    • Export Citation
  • FrithG.J.T.NicholsD.G.1975Effects of nitrogen fertilizer applications to part of a root systemBritish Columbia Orchardist1510

  • GazulaA.SimonneE.DukesM.HochmuthG.HochmuthB.StudstillD.2006Optimization of drainage lysimeter design for field determination of nitrogen loadsProc. Florida State Hort. Soc.119213233

    • Search Google Scholar
    • Export Citation
  • GeorgeT.S.RichardsonA.E.SmithJ.B.HadobasP.A.SimpsonR.J.2005Limitations to the potential of transgenic Trifolium subterraneum L. plants that exude phytase when grown in soils with a range of organic P contentPlant Soil278262274

    • Search Google Scholar
    • Export Citation
  • HalvorsonA.D.FollettR.F.BartoloM.E.SchweissingF.C.2002Nitrogen fertilizer use efficiency of furrow-irrigated onion and cornAgron. J.94442449

    • Search Google Scholar
    • Export Citation
  • HochmuthG.J.HanlonE.NagataR.SnyderG.SchuenemanT.2003aFertilization recommendations of crisphead lettuce grown on organic soils in Florida15 Mar. 2008<http://edis.ifas.ufl.edu/WQ114>.

    • Export Citation
  • HochmuthG.J.HanlonE.NagataR.SnyderG.SchuenemanT.2003bFertilization of sweet corn, celery, romaine, escarole, endive, and radish on organic soils in FloridaUniv. Florida, Inst. Food Agr. Sci., Bul. 31315 Mar. 2008<http://edis.ifas.ufl.edu/CV008>.

    • Export Citation
  • HochmuthR.DinkinD.SweatM.SimonneE.2003cExtension programs in northeastern Florida help growers produce quality strawberries by improving water and nutrient managementUniv. Florida, Inst. Food Agr. Sci., HS 95615 Mar. 2008<http://edis.ifas.ufl.edu/HS190>.

    • Export Citation
  • HutchinsonC.M.2004Influence of a controlled release nitrogen fertilizer program on potato (Solanum tuberosum L.) tuber yield and qualityActa Hort.68499102

    • Search Google Scholar
    • Export Citation
  • JianJunC.GabelmanW.H.1995Isolation of tomato stains varying in potassium acquisition using a sand-zeolite culture systemPlant Soil1766570

    • Search Google Scholar
    • Export Citation
  • JinKiuL.ShuBinS.LiJinJ.WeiC.QiRongS.2006The mechanism of nitrate accumulation in pakchoi [Brassica campestris L ssp.chinensis (L.)]Plant Soil282291300

    • Search Google Scholar
    • Export Citation
  • KhahE.M.KakavaE.MavromatisA.ChachalisD.GoulasC.2006Effect of grafting on growth and yield of tomato (Lycopersicon esculentum Mill.) in greenhouse and open-fieldJ. Appl. Hort.837

    • Search Google Scholar
    • Export Citation
  • LecompteF.BressoudF.ParesL.De BruyneF.2008Root and nitrate distribution as related to the critical plant N status of a fertigated tomato cropJ. Hortic. Sci. Biotechnol.83223231

    • Search Google Scholar
    • Export Citation
  • LeeJ.M.1994Cultivation of grafted vegetables. I. Current status, grafting methods, and benefitsHortScience29235239

  • LeeS.G.2007Production of high quality vegetable seedling graftsActa Hort.759169174

  • LiY.C.KlassenW.LambertsM.OlczykT.2006aBush and pole bean production in Miam–Dade County, Florida15 Mar. 2008<http://edis.ifas.ufl.edu/TR005>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006bCabbage production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85415 Mar. 2008<http://edis.ifas.ufl.edu/TR006>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006cCucumber production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85515 Mar. 2008<http://edis.ifas.ufl.edu/TR007>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006dEggplant production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85615 Mar. 2008<http://edis.ifas.ufl.edu/TR008>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006eOkra production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85715 Mar. 2008<http://edis.ifas.ufl.edu/TR009>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006fPepper production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85915 Mar. 2008<http://edis.ifas.ufl.edu/TR010>.

    • Export Citation
  • LiY.C.KlassenW.O'HairS.LambertsM.OlczykT.2006gPotato production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 86015 Mar. 2008<http://edis.ifas.ufl.edu/TR011>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006hSummer squash production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 86115 Mar. 2008<http://edis.ifas.ufl.edu/TR012>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006iSweet corn production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 86215 Mar. 2008<http://edis.ifas.ufl.edu/TR013>.

    • Export Citation
  • LiY.C.KlassenW.LambertsM.OlczykT.2006jTomato production in Miami–Dade County, FloridaUniv. Florida, Inst. Food Agr. Sci., HS 85815 Mar. 2008<http://edis.ifas.ufl.edu/TR014>.

    • Export Citation
  • LinaresJ.ScholbergJ.BooteK.ChaseC.A.FergusonJ.J.McSorleyR.2008Use of the crop weed index to evaluate weed suppression by cover crops in organic citrus orchardsHortScience432734

    • Search Google Scholar
    • Export Citation
  • MacaigneP.ParentL.E.AnctilF.2008Single-hole soil sampling for nitrogen in the potato hillCommun. Soil Sci. Plant Anal.3914861492

  • MigliaccioK.W.YuncongL.TraffordH.EvansE.2006A simple lysimeter for soil water sampling in south FloridaUniv. Florida, Inst. Food Agr. Sci., Circ. ABE 36115 Mar. 2008<http://edis.ifas.ufl.edu/AE387>.

    • Export Citation
  • Muñoz-ArboledaF.MylavarapuR.HutchinsonC.2006Root distribution under seepage-irrigated potatoes in northeast FloridaAmer. J. Potato Res.83463472

    • Search Google Scholar
    • Export Citation
  • Muñoz-ArboledaF.MylavarapuR.HutchinsonC.PortierK.2008Nitrate-nitrogen concentrations in the perched ground water under seepage-irrigated potato cropping systemsJ. Environ. Qual.37387394

    • Search Google Scholar
    • Export Citation
  • O'SullivanJ.GabelmanW.H.GerloffG.C.1974Variations in efficiency of nitrogen utilization in tomatoes (Lycopersicon esculentum Mill.) grown under nitrogen stressJ. Amer. Soc. Hort. Sci.99543547

    • Search Google Scholar
    • Export Citation
  • OikehS.O.CarskyR.J.KlingJ.G.ChudeV.O.HorstW.J.2003Differential N uptake by maize cultivars and soil nitrate dynamics under N fertilization in West AfricaAgr. Ecosyst. Environ.100181191

    • Search Google Scholar
    • Export Citation
  • OlsonS.M.SimonneE.H.2007Vegetable production handbook for Florida 2007–2008Vance PublishingLenexa, KS

    • Export Citation
  • PackJ.E.HutchinsonC.M.SimonneE.H.2006Evaluation of controlled-release fertilizers for northeast Florida chip potato productionJ. Plant Nutr.2913011313

    • Search Google Scholar
    • Export Citation
  • PampolinoM.F.UrushiyamaT.HatanoR.2000Detection of nitrate leaching through bypass flow using pan lysimeter, suction cup, and resin capsuleSoil Sci. Plant Nutr.46703711

    • Search Google Scholar
    • Export Citation
  • PaudelK.P.AdhikariM.MartinN.R.Jr2004Evaluation of broiler litter transportation in northern Alabama, USAJ. Environ. Manage.731523

  • PeraltaJ.M.StockleC.O.2002Dynamics of nitrate leaching under irrigated potato rotation in Washington State: A long-term simulation studyAgric. Ecosyst. Environ.882334

    • Search Google Scholar
    • Export Citation
  • PotterT.L.BoschD.D.JooH.SchafferB.Muñoz-CarpenaR.2007Summer cover crops reduce atrazine leaching to shallow groundwater in Southern FloridaJ. Environ. Qual.3613011309

    • Search Google Scholar
    • Export Citation
  • QaryoutiM.M.QawasmiW.HamdanH.EdwanM.2007Tomato fruit yield and quality as affected by grafting and growing systemActa Hort.741199206

    • Search Google Scholar
    • Export Citation
  • RajputT.B.S.PatelN.2006Water and nitrate movement in drip-irrigated onion under fertigation and irrigation treatmentsAgr. Water Mgt.79293311

    • Search Google Scholar
    • Export Citation
  • RamosC.AgutA.LidónA.L.2002Nitrate leaching in important crops of the Valencian Community region (Spain)Environ. Pollut.118215223

  • RiceR.W.IzunoF.T.2001Calculating nutrient loadsUniv. Florida, Inst. Food Agr. Sci., Res. Tech. Bul. 90615 Mar. 2008<http://edis.ifas.ufl.edu/AE149>.

    • Export Citation
  • RomicD.RomicM.BorosicJ.PoljakM.2003Mulching decreases nitrate leaching in bell pepper (Capsicum annuum L.) cultivationAgr. Water Mgt.608797

    • Search Google Scholar
    • Export Citation
  • SainjuU.M.SinghB.P.RahmanS.ReddyV.R.1999Soil nitrate–nitrogen under tomato following tillage, cover cropping, and nitrogen fertilizationJ. Environ. Qual.2818371844

    • Search Google Scholar
    • Export Citation
  • SchenkM.K.2006Nutrient efficiency in vegetable cropsActa Hort.7002123

  • SchombergH.H.MartiniN.L.Diaz-PerezJ.C.PhatakS.C.BalkomK.S.BhardwajH.L.2007Potential for using sun hemp as a source of biomass and nitrogen for the piedmont and coastal plain regions of the southeastern USAAgron. J.9914481457

    • Search Google Scholar
    • Export Citation
  • SepaskhahA.R.YousefiF.2007Effect of zeolite application on nitrate and ammonium retention of a loamy soil under saturated conditionsAust. J. Soil Res.45368373

    • Search Google Scholar
    • Export Citation
  • ShahnazariA.AhmadiS.H.LaerkeP.E.FuLaiL.PlauborgF.JacobsenS.E.JensenC.R.AndersenM.N.2008Nitrogen dynamics in the soil-plant system under deficit and partial root-zone drying irrigation strategies in potatoesEur. J. Agron.286573

    • Search Google Scholar
    • Export Citation
  • SharifiM.ZebarthB.J.2006Nitrate influx kinetic parameters of five potato cultivars during vegetative growthPlant Soil2289199

  • SharifiM.ZebarthB.J.ColemanW.2007Screening for nitrogen-use efficiency in potato with a recirculating hydroponic systemCommun. Plant Sci. Soil Anal.38359370

    • Search Google Scholar
    • Export Citation
  • SimonneE.H.DukesM.D.HamanD.Z.2007Principles and practices for irrigation managementUniv. Florida, Inst. Food Agr. Sci., AE26015 Mar. 2008<http://edis.ifas.ufl.edu/CV107>.

    • Export Citation
  • SimonneE.H.HutchinsonC.M.2005Controlled release fertilizer for vegetable crops: Teaching new tricks to an old dogHortTechnology151424

  • SimonneE.H.Ozores-HamptonM.2006Challenges and opportunities for extension educators involved in best management practicesHortTechnology16403407

    • Search Google Scholar
    • Export Citation
  • SimonneE.H.StudstillD.W.HochmuthR.C.JonesJ.T.StarlingC.W.2005On-farm demonstration of soil water movement in vegetables grown with plasticultureUniv. Florida, Inst. Food Agr. Sci., HS 100815 Mar. 2008<http://edis.ifas.ufl.edu/HS251>.

    • Export Citation
  • SivapalanS.2006Benefits of treating a sandy soil with a crosslinked-type polyacrylamideAust. J. Exp. Agr.46579584

  • StockleC.O.MartinS.A.CampbellG.S.1994CropSyst, a cropping systems simulation model: Water/nitrogen budgets and crop yieldAgr. Syst.46335359

    • Search Google Scholar
    • Export Citation
  • SwiaderJ.M.ChvanY.FreijiF.G.1994Genotypic differences in nitrate uptake and utilization efficiency in pumpkin hybridsJ. Plant Nutr.1716871699

    • Search Google Scholar
    • Export Citation
  • SyvertsenJ.P.JifonJ.L.2001Frequent fertigation does not affect citrus tree growth, fruit yield, nitrogen uptake, and leaching lossesProc. Florida State Hort. Soc.1148893

    • Search Google Scholar
    • Export Citation
  • TanakaT.SatoT.1997Growth and nutrient absorption characteristics of three commercial cabbage cultivars under varying nitrogen levelsJpn. J. Soil Sci. Plant Nutr.68493500

    • Search Google Scholar
    • Export Citation
  • VachereC.A.LochR.J.RaineS.R.2003Effect of polyacrylamide additions on infiltration and erosion of disturbed landsAust. J. Soil Res.4115091520

    • Search Google Scholar
    • Export Citation
  • VázquezN.PardoaA.SusoaM.L.QuemadabM.2006Drainage and nitrate leaching under processing tomato growth with drip irrigation and plastic mulchingAgr. Ecosyst. Environ.112313323

    • Search Google Scholar
    • Export Citation
  • XiangRongW.ZhengQuanW.YouZhiH.JianCunG.DaLiG.LiM.2005Variations of fine root diameter with root order in manchurian ash and duhurian larch plantationsActa Phytoecol. Sin.29871877

    • Search Google Scholar
    • Export Citation
  • YaffaS.SainjuU.M.SinghB.P.2000Fresh market tomato yield and soil nitrogen as affected by tillage, cover cropping, and nitrogen fertilizationHortScience3512581262

    • Search Google Scholar
    • Export Citation
  • ZhuJ.H.LiX.L.ChristieP.LiJ.L.2005Environmental implications of low nitrogen use efficiency in excessively fertilized hot pepper (Capsicum frutescens L.) cropping systemsAgric. Ecosyst. Environ.1117080

    • Search Google Scholar
    • Export Citation
  • ZotarelliL.DukesM.D.ScholbergJ.M.HanselmanT.FemminellaK.L.Muñoz-CarpenaR.2008Nitrogen and water use efficiency of zucchini squash for a plastic mulch bed system on a sandy soilScientia Hort.116816

    • Search Google Scholar
    • Export Citation
  • ZotarelliL.ScholbergJ.M.DukesM.D.Muñoz-CarpenaR.2007Monitoring of nitrate leaching in sandy soils: Comparison of three methodsJ. Environ. Qual.36953962

    • Search Google Scholar
    • Export Citation
  • ZreigA.SharifA.AmayrehJ.2007Erosion control of arid land in Jordan with two anionic polyacrylamidesArid Land Res. Manage.21315328

  • ZvomuyaF.RosenC.J.RusselleM.P.GuptaS.C.2003Nitrate leaching and nitrogen recovery following application of polyolefin-coated urea to potatoJ. Environ. Qual.32480489

    • Search Google Scholar
    • Export Citation

Article Information

Google Scholar

Related Content

Article Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 261 261 49
PDF Downloads 29 29 1