Florida ranks first in the production of tomato in the United States [U.S. Department of Agriculture (USDA), 2011] and uses ≈30,000 acres for production (USDA, 2018). Tomato production systems involve intensive management of nutrients and water on typically sandy textured soils. Optimizing applications of nutrient and water and their use efficiencies is, therefore, important for minimizing potential losses of nutrients to the environment, particularly nitrogen (N), in sandy soils. Synthetic N fertilizer is a relatively low-cost input resulting in potential excessive applications. This ultimately leads to leaching of N into groundwater through nitrate-nitrogen (NO3-N) pollution (Paltineanu et al., 1980) and degrades surface water bodies through eutrophication (Carpenter et al., 1998). In most agricultural soils, NO3-N is the dominant N form available for crop accumulation (Mengel and Kirkby, 2001), where agricultural sandy soils can intensify NO3-N leaching.
Nitrogen is a common limiting factor for tomato production in the southeastern United States (Everett, 1976; Locascio et al., 1997; Rhoads et al., 1996), resulting in significant N use. In Florida, the recommended rate of N fertilization for tomato production is 200 lb/acre (Mylavarapu et al., 2017a), although commercial growers may apply more than double this amount (357–500 lb/acre) (Everett, 1976; Rhoads et al., 1996). With increases in the use of N fertilizer occurring, it is critical to produce information on fertilizer accumulation by the crop to improve production practices that can increase efficiency and decrease N fertilizer loss.
Nitrogen use efficiency (NUE) of agricultural systems is estimated at 50% (Smil, 1999), where unused N fertilizer may remain in the soil or be subject to denitrification, volatilization, and leaching to groundwater (Carpenter et al., 1998). Nitrogen use efficiency is defined as the N accumulation by plants divided by the amount of N fertilizer applied. Increasing NUE in agricultural production systems is of critical importance because the consumption and demand for N fertilizer will continue to grow as populations increase (Xu et al., 2012). In 2008, about 162 million tonnes of N, phosphorous (P), and potassium (K) fertilizer was used and has increased to 200 million tonnes of fertilizer in 2018 [Food and Agriculture Organization of the United Nations (FAO), 2015]. Of this 200 million tonnes, 119 million tonnes came from N alone (FAO, 2015). Currently, researchers and government agencies are attempting to look at optimizing NUE in agricultural production while minimizing negative impacts to the environment. For example, the Florida Department of Agriculture and Consumer Services (FDACS) implemented best management practices (BMPs) to reduce nutrient loading from agricultural production into bodies of water (FDACS, 2015). Efforts have included the improvement and implementation of soil test recommendations and other cultural practices to improve NUE of agricultural systems and reduce leaching (Way, 2007). For tomato production on sandy soils in Florida, BMPs include drip irrigation, splitting N fertilizer applications (13 weekly applications), and mulched beds, all of which help improve the NUE.
In addition to improving fertilizer N efficiency in tomato production systems, the agronomic apparent recovery of N fertilizer (APR) will be studied. The agronomic calculation of APR is defined as the difference in N accumulation (pounds per acre) between plots receiving fertilizer and unfertilized plots, and it is in proportion to the amount of N fertilizer applied. The APR index evaluates the ability of the crop to absorb soil N, where decreases in APR occur when N supply exceeds crop N demand (Greenwood and Hunt, 1986). A decline in APR, therefore, typically occurs when N fertilizer rates are increased. An APR value of zero would indicate that N accumulation of the unfertilized crops did not differ from those that were fertilized with N fertilizer. In other words, the plant likely took up native soil N primarily. On the other hand, an APR value of 100% indicates that N accumulation of the crop was higher than what was applied as N fertilizer (Craswell and Godwin, 1984; Mengel et al., 2006). Therefore, determining APR in vegetable production systems is important to ascertain the efficiency of applied N fertilizer to a system that may or may not provide sufficient native soil N to the crop.
Information on NUE and APR could aid in providing additional information on determining the efficiency of current management practices related to rate and timing of N fertilizer applications (Zemenchik and Albrecht, 2002). Limited information is available where NUE and APR are compared and evaluated together (Zemenchik and Albrecht, 2002), especially in the case of evaluating the efficiency of N fertilizer application on vegetable production systems. Therefore, a study was conducted on determining the efficiency of applied N fertilizer on tomato produced on sandy soils, using NUE and APR as indices of evaluating efficiency. Thus, our objectives were to determine the effect of N fertilization rate on the responses of tomato, including 1) N accumulation in plant tissues, 2) crop N requirement, and 3) apparent recovery and efficiency of N.
CarpenterS.R.CaracoN.F.CorrellD.L.HowarthR.W.SharpleyA.N.SmithV.H.1998Nonpoint pollution of surface waters with phosphorus and nitrogenEcol. Appl.8559568
FixenP.BrentrupF.BruulsemaT.W.GarciaF.NortonR.ZingoreS.2015Nutrient/fertilizer use efficiency: Measurement current situation and trends p. 8–38. In: Managing water and fertilizer for sustainable agricultural intensification. 11 Nov. 2019. <http://www.iwmi.cgiar.org/Publications/Books/PDF/managing_water_and_fertilizer_for_sustainable_agricultural_intensification.pdf>
Florida Department of Agriculture and Consumer Services (FDACS)2015Water quality/quantity best management practices for Florida vegetable and agronomic crops. 10 Jan. 2020. <https://www.fdacs.gov/content/download/77230/file/vegAgCropBMP-loRes.pdf>
Food and Agriculture Organization of the United Nations (FAO).2015World fertilizer trends and outlook to 2018. 16 Feb. 2018. <http://www.fao.org/3/a-i4324e.pdf>
GreenwoodD.J.HuntJ.1986Effect of nitrogen fertilizer on the nitrate contents of field vegetables grown in BritainJ. Sci. Food Agr.37373383
HeuvelinkE.2005Tomatoes. CABI Publ. Cambridge MA
HochmuthG.CordascoK.2000A summary of N P and K research with tomato in Florida. Vegetable Nutrition Management Series. Hort. Sci. Dept. Florida Coop. Ext. Serv. Inst. Food Agr. Sci. Univ. Florida Gainesville
HochmuthG.HanlonE.2014A summary of N P and K research with tomato in Florida. Univ. Florida Inst. Food Agr. Sci. SL355. 20 Nov. 2018. <http://edis.ifas.ufl.edu/cv236>
JanssonS.L.PerssonJ.1982Mineralization and immobilization of soil nitrogen p. 229–248. In: F.J. Stevenson (ed.). Nitrogen in agricultural soils. Amer. Soc. Agron. Madison WI
KadiyalaM.D.M.MylavarapuR.S.LiY.C.ReddyG.B.ReddyK.R.ReddyM.D.2014Uptake efficiency of 15N-urea in flooded and aerobic rice fields under semi-arid conditionsPaddy Water Environ.13545556
LocascioS.J.HochmuthG.J.RhoadsF.M.OlsonS.M.SmajstrlaA.G.HanlonE.A.1997Nitrogen and potassium application scheduling effects on drip-irrigated tomato yield and leaf tissue analysisHortScience32230235
Masclaux-DaubresseC.Daniel-VedeleF.DechorgnatJ.ChardonF.GaufichonL.SuzukiA.2010Nitrogen uptake, assimilation and remobilization in plants: Challenges for sustainable and productive agricultureAnn. Bot.10511411157
MengelK.KirkbyE.A.2001Nitrogen. Principles of plant nutrition. Kluwer Academic Publ. Dordrecht The Netherlands
MengelK.HutschB.KaneY.2006Nitrogen fertilizer application rates on cereal crops according to available mineral and organic soil nitrogenEur. J. Agron.24343348
MylavarapuR.HochmuthG.LiuG.2017aUF/IFAS standardized nutrient recommendations for vegetable crop production in Florida. Soil Water Sci. IFAS Coop. Ext. Serv. Univ. Florida CIR1152
MylavarapuR.S.d’AngeloW.WilkinsonN.MoonD.2017bUF/IFAS extension soil testing laboratory (ESTL) analytical procedures and training manual. Soil Water Sci. IFAS Coop. Ext. Serv. Univ. Florida Circ. 1248
PaltineanuI.C.HeraC.PaltineanuR.IdriceunuA.EliadeG.SuteuG.BologaM.CanaracheA.PostolacheT.ApostolI.1980Irrigation water and N fertilizer application efficiencies for reduction of water and N losses and for water pollution control p. 169–193. In: Proc. Soil Nitrogen as Fertilizer or Pollutant Res. Coordination Mtg. Piracicaba Brazil 3–7 July 1978 Intl. Atomic Energy Agency Vienna Austria
RhoadsF.M.OlsonS.M.HochmuthG.J.HanlonE.A.1996Yield and petiole-sap nitrate levels of tomato with N rates applied preplant or fertigatedProc. Soil Crop Sci. Soc. Fla.552022
SatoS.PeetM.M.ThomasJ.F.2000Physiological factors limit fruit set of tomato (Lycopersicon esculentum Mill.) under chronic, mild heat stressPlant Cell Environ.23719726
SyersJ.K.JohnstonA.E.CurtinD.2008Efficiency of soil and fertilizer phosphorus use reconciling changing concepts of soil phosphorus behavior with agronomic information. FAO Fert. Plant Nutr. Bul. 18. 14 Nov. 2019. <http://www.fao.org/3/a-a1595e.pdf>
U.S. Department of Agriculture2011Florida agriculture by the numbers. 14 Nov. 2019. <https://www.nass.usda.gov/Statistics_by_State/Florida/Publications/Annual_Statistical_Bulletin/FL_Agriculture_Book/2011/2011%20FL%20Ag%20by%20the%20Numbers.pdf>
U.S. Department of Agriculture2017Web soil survey. 13 Jan. 2018. <http://websoilsurvey.sc.egov.usda.gov>
U.S. Department of Agriculture2018Vegetables 2017 summary. 14 Nov. 2019. <https://downloads.usda.library.cornell.edu/usda-esmis/files/02870v86p/5425kd81z/9019s517t/VegeSumm-02-13-2018.pdf>
WayP.L.2007Development of a functional, widely accepted and adopted BMP program in response to government regulationAmer. J. Potato Res.843946
ZemenchikR.A.AlbrechtK.A.2002Nitrogen use efficiency and apparent nitrogen recovery of Kentucky bluegrass, smooth bromegrass, and orchardgrassAgron. J.94421428
ZotarelliL.ScholbergJ.M.DukesM.D.Muñoz-CarpenaR.2007Monitoring of nitrate leaching in sandy soils: Comparison of three methodsJ. Environ. Qual.36953962
ZotarelliL.ScholbergJ.M.DukesM.D.Muñoz-CarpenaR.IcermanJ.2009aTomato yield, biomass accumulation, root distribution and irrigation water use efficiency on a sandy soil, as affected by nitrogen rate and irrigation schedulingAgr. Water Manage.962334
ZotarelliL.DukesM.D.ScholbergJ.M.Muñoz-CarpenaR.IcermanJ.2009bTomato nitrogen accumulation and fertilizer use efficiency on sandy soil, as affected by nitrogen rate and irrigation schedulingAgr. Water Manage.9612471258
ZuraiqiS.QawasmiW.DeekI.MohammadM.J.2002Management of nitrogen fertigation of tomato with the use of 15N technology. Joint FAO/Intl. Atomic Energy Agency Div. Nuclear Techniques in Food Agr. Vienna Austria