No description available.

Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Horticulture in the Faculty of Applied Sciences at the Cape Peninsula University of Technology 2013 / This study evaluated the effects of different pH levels and supplementary phosphorous concentrations on Salvia chamelaeagnea grown in hydroponics. The treatments consisted of 12 treatments of 4 differing nutrient solutions offering: low concentration of supplementary P (control), balanced concentration of supplementary P, moderate concentration of supplementary P and a high concentration of supplementary P at 3 differing pH levels. Each treatment was replicated 10 times. The objectives of this study were to asses the effect of supplementary phosphorous concentrations and 3 different pH levels on the growth, development and chlorophyll responses of Salvia chamelaeagnea grown hydroponically. Growth and development was recorded by measuring weekly heights, numbers of basal shoots, stem diameters and the number of branches, while root length and wet and dry weights of roots and shoots were measured post harvest. Chlorophyll responses were recorded by measuring weekly SPAD-502 measurements while post harvest DMSO analysis of chlorophyll A, B and total chlorophyll were recorded along with nutrient uptake levels of N, P,K, Ca, Mg, Na, Mn, Fe, Cu, Zn and B in the plant leaves. This study has shown that the use of a hydroponic nutrient system offering a moderate concentration of supplementary P at a pH level of 4 significantly influences the growth and development of Salvia chamelaeagnea grown in hydroponics. Plants treated with a pH level of 4 generally produced higher wet and dry shoot weights, root lengths, stem diameters, basal shoot numbers, branch numbers, and plant heights than that of the control and all treatments delivering nutrients at a pH level of 6 and 8. Although no one treatment offering supplementary P produced consistently high results, in most cases all the plants receiving supplementary P at a pH level of 4 outperformed the pH 6 and pH 8 treatments receiving the same amount of supplementary P. This indicates that at a pH level of 4 the mineral nutrient availability of a nutrient solution is at an adequate level for the growth and development of Salvia chamelaeagnea. Furthering studies into the effects of arbuscular mycorrhiza on the uptake of mineral nutrients, root morphology and growth and development are recommended.

Depois que a agricultura brasileira passou a ser destacada no cenário de das pesquisas científicas, o grande desafio passou a ser a padronização de produtividade em todo território nacional. Um dos principais focos vem sendo a região semi-árida pela sua escassez de água, tanto quantitativa quanto qualitativa, por ser uma região com baixo índice de precipitação e por suas águas subterrâneas normalmente serem águas salobras. Com este desafio nacional, vem se destacando a hidroponia em alguns Estados, pelo uso da água racionalmente. Com este aumento do uso da hidroponia vem aparecendo algumas dificuldades devido à falta de informações sobre este sistema. Contudo, estudos a ser realizados visando aumentar informações sobre uso de águas salobras em hidroponia, e também buscando informação sobre os níveis de resposta das culturas à salinidade, são de fundamental importância para aperfeiçoar os investimentos em produções hidropônicas, principalmente na região Nordeste do Brasil. Tendo em vista a falta de informação para a cultura do agrião hidropônico, o objetivo deste trabalho foi: averiguar a resposta à salinidade da cultura do agrião, em hidroponia e em solo; propor um manejo para a melhor utilização do sistema, com águas salinas. O experimento foi desenvolvido no Departamento de Engenharia Rural da Escola Superior Luiz de Queiroz ESALQ-USP, em uma casa de vegetação do tipo arco simples. Utilizou-se um sistema de hidroponia composta por 32 unidades experimentais, que já se encontravam instaladas. Cada sistema hidropônico representou uma parcela independente. Para averiguar a resposta aos sais pelo agrião em sistema hidropônico NFT e no solo, foram avaliados oito níveis de salinidade da solução nutritiva produzidos com NaCl, sendo a solução nutritiva e mais sete níveis de salinidade da água. Foi observado, que o níveis menores de sais, o agrião se desenvolveu melhor em relação aos níveis maiores. Foi observado também que a resposta da cultura à salinidade foi melhor nos sistemas hidropônicos. Notou-se também que os principais sintomas da salinidade foram o nanismo, coloração escura das folhas e suas folhas ficaram coriáceas. Após o experimento, conclui-se que os tratamentos salinos influenciaram significativamente todos os parâmetros de rendimento da cultura, tanto na hidroponia quanto no solo; houve melhor desenvolvimento das plantas sob salinidade na hidroponia, quando confrontado ao solo; o consumo de água palas plantas na hidroponia foi influenciado pela salinidade. / After the Brazilian agriculture started to be outstanding in the scenery of the scientific researches, the great challenge started to be the productivity standardization in whole national territory. One of the main focus is being the semi-arid area for its water scarcity, so much quantitative as qualitative, for being an area with low annual precipitation and for their underground waters be usually salty waters. With this national challenge, it been spreading the soilless in some States, to improve the water use. With this increase soilless use it is appearing some difficulties due the lack of the information on this system. However, studies to be accomplished seeking to increase information on use of salty waters in soilless, and also looking for information on the answer salinity levels crop, are of fundamental importance to improve the investments in productions hydroponics, mainly in the Northeast of Brazil. Tends in view of the information lack for the hydroponic watercress crop, the objective of this work was: determine the threshold salinity of the crop watercress, in soilless and in soil; to propose a handling for the best system use, with saline waters. The experiment was developed in the Department of Rural Engineering of the Superior School \'Luiz of Queiroz\' ESALQ-USP, in a greenhouse of the type simple arch. A soilless system was used composed by 32 experimental units, that already installed previously. Each system hydroponics represented an independent portion. To discover the answer to the salts for the watercress in system hydroponics NFT and in the soil, they were evaluated eight salinity levels of the nutritious solution produced with NaCl, being the solution nutritious and more seven salinity levels of the water. It was observed, that in smaller levels of salts, the watercress grew better in relation to the larger levels. It was also observed that the answer crop to the salinity was better in the systems hydroponics. It was also noticed that the main symptoms of the salinity were the nanism, dark coloration leaves and their leaves were coriaceous. After the experiment, it is concluded that the saline treatments influenced significantly all income parameters crop, both in soilless and in soil; there was better development of the plants under salinity in the soilless, compared to the soil; the water consumption peaks plants in the soilless was influenced by the salinity.

Depois que a agricultura brasileira passou a ser destacada no cenário de das pesquisas científicas, o grande desafio passou a ser a padronização de produtividade em todo território nacional. Um dos principais focos vem sendo a região semi-árida pela sua escassez de água, tanto quantitativa quanto qualitativa, por ser uma região com baixo índice de precipitação e por suas águas subterrâneas normalmente serem águas salobras. Com este desafio nacional, vem se destacando a hidroponia em alguns Estados, pelo uso da água racionalmente. Com este aumento do uso da hidroponia vem aparecendo algumas dificuldades devido à falta de informações sobre este sistema. Contudo, estudos a ser realizados visando aumentar informações sobre uso de águas salobras em hidroponia, e também buscando informação sobre os níveis de resposta das culturas à salinidade, são de fundamental importância para aperfeiçoar os investimentos em produções hidropônicas, principalmente na região Nordeste do Brasil. Tendo em vista a falta de informação para a cultura do agrião hidropônico, o objetivo deste trabalho foi: averiguar a resposta à salinidade da cultura do agrião, em hidroponia e em solo; propor um manejo para a melhor utilização do sistema, com águas salinas. O experimento foi desenvolvido no Departamento de Engenharia Rural da Escola Superior Luiz de Queiroz ESALQ-USP, em uma casa de vegetação do tipo arco simples. Utilizou-se um sistema de hidroponia composta por 32 unidades experimentais, que já se encontravam instaladas. Cada sistema hidropônico representou uma parcela independente. Para averiguar a resposta aos sais pelo agrião em sistema hidropônico NFT e no solo, foram avaliados oito níveis de salinidade da solução nutritiva produzidos com NaCl, sendo a solução nutritiva e mais sete níveis de salinidade da água. Foi observado, que o níveis menores de sais, o agrião se desenvolveu melhor em relação aos níveis maiores. Foi observado também que a resposta da cultura à salinidade foi melhor nos sistemas hidropônicos. Notou-se também que os principais sintomas da salinidade foram o nanismo, coloração escura das folhas e suas folhas ficaram coriáceas. Após o experimento, conclui-se que os tratamentos salinos influenciaram significativamente todos os parâmetros de rendimento da cultura, tanto na hidroponia quanto no solo; houve melhor desenvolvimento das plantas sob salinidade na hidroponia, quando confrontado ao solo; o consumo de água palas plantas na hidroponia foi influenciado pela salinidade. / After the Brazilian agriculture started to be outstanding in the scenery of the scientific researches, the great challenge started to be the productivity standardization in whole national territory. One of the main focus is being the semi-arid area for its water scarcity, so much quantitative as qualitative, for being an area with low annual precipitation and for their underground waters be usually salty waters. With this national challenge, it been spreading the soilless in some States, to improve the water use. With this increase soilless use it is appearing some difficulties due the lack of the information on this system. However, studies to be accomplished seeking to increase information on use of salty waters in soilless, and also looking for information on the answer salinity levels crop, are of fundamental importance to improve the investments in productions hydroponics, mainly in the Northeast of Brazil. Tends in view of the information lack for the hydroponic watercress crop, the objective of this work was: determine the threshold salinity of the crop watercress, in soilless and in soil; to propose a handling for the best system use, with saline waters. The experiment was developed in the Department of Rural Engineering of the Superior School \'Luiz of Queiroz\' ESALQ-USP, in a greenhouse of the type simple arch. A soilless system was used composed by 32 experimental units, that already installed previously. Each system hydroponics represented an independent portion. To discover the answer to the salts for the watercress in system hydroponics NFT and in the soil, they were evaluated eight salinity levels of the nutritious solution produced with NaCl, being the solution nutritious and more seven salinity levels of the water. It was observed, that in smaller levels of salts, the watercress grew better in relation to the larger levels. It was also observed that the answer crop to the salinity was better in the systems hydroponics. It was also noticed that the main symptoms of the salinity were the nanism, dark coloration leaves and their leaves were coriaceous. After the experiment, it is concluded that the saline treatments influenced significantly all income parameters crop, both in soilless and in soil; there was better development of the plants under salinity in the soilless, compared to the soil; the water consumption peaks plants in the soilless was influenced by the salinity.

No description available.

The objectives for this research were to determine: 1) whether sulfated micronutrient addition increased growth of container-grown pin oak (Quercus palustris MuÌ nchh) and Japanese maple (Acer palmatum Thunb.) seedlings by supplying micronutrients, sulfur, or decreasing substrate pH, 2) S requirements of Q. palustris and A. palmatum container-grown in a pine bark (PB) substrate, and 3) if there are any conditions that will affect these S requirements. Container grown Q. palustris and A. palmatum seedlings were grown in PB, amended (or not) with the following treatments: control (no amendment), Micromax (commercial micronutrient fertilizer [sulfate form]), K2SO4, H2SO4, HCl, chelated micronutrients, elemental S, or CaSO4. Dry weights of plants in all treatments supplying S were higher than for plants receiving no S. These data indicate that S, not micronutrient application, was the primary cause of increased growth from the addition of sulfated micronutrients. In other experiments these two species were fertilized with 8 different concentrations of S application (0, 1, 2, 5, 10, 20, 40, or 80 mg·liter-1). Regression analysis revealed dry weights of both species were near maximum at the extrapolated application concentration of 30 mg·liter-1 S, which corresponded to approximately 15 and 7 mg·liter-1 S in substrate solution for oak and maple, respectively. In another set of experiments plants were fertilized with Micromax or FeSO4 with or without lime. In the plus lime treatments (substrate pH 6.1), plant dry weights were higher in Micromax fertilized plants than for FeSO4 fertilized plants. However, in the minus lime treatment (substrate pH 4.5), FeSO4 addition effectively supplied S to plants. / Master of Science

Growing landscape trees in containers is a common practice in the nursery industry. In the southeastern United States, pine bark is often used as a container substrate, and two common amendments to pine bark are lime and micronutrients. In this study, three experiments were conducted to determine the effect of these amendments on the growth of a wide range of landscape tree species grown in pine bark. In the first experiment, nine species of landscape trees [Acer palmatum (Japanese maple), Acer saccharum (sugar maple), Cercis canadensis (redbud), Cornus florida (flowering dogwood), Cornus kousa (kousa dogwood), Koelreuteria paniculata (golden-rain tree), Magnolia x soulangiana (magnolia), Nyssa sylvatica (blackgum), and Quercus palustris (pin oak)] were grown from seed in two pine barks: pH 4.7 (low) and 5.1 (high). Preplant amendment treatments to each pine bark (Pinus taeda) were: with or without dolomitic limestone (3.57 kg.m-3) and with or without micronutrients (0.9 kg.m-3, Micromax™). The same experiment was repeated using Koelreuteria paniculata and Quercus palustris, the same lime and micronutrient treatments, and two pine barks: pH 5.1 (low) and 5.8 (high). In both experiments, micronutrients increased shoot dry mass and height for all species, while lime decreased shoot dry mass and height for all species. Effect of bark type in the first experiment was variable, while shoot dry mass and height were highest in the low pH bark when the experiment was repeated. Substrate solution element concentrations increased when micronutrients were added, decreased when lime was added, and in general, concentrations were higher in low pH bark than in high pH bark. In the third experiment, Koelreuteria paniculata was grown from seed in pine bark amended with 0, 1.2, 2.4, or 3.6 kg.m-3 dolomitic limestone and 0 or 0.9 kg.m-3 micronutrients (Micromax™). Initial pH for each lime rate was 4.0, 4.5, 5.0, and 5.5, respectively. Adding micronutrients increased shoot dry mass and height. Lime increased growth only at the 1.2 kg.m-3 rate. In general, substrate solution element concentrations increased when micronutrients were added and decreased when lime was added. In all three experiments, adding micronutrients was necessary regardless of pine bark pH, while adding lime was not necessary. / Master of Science

Nitrogen (N) fertilizer is a required mineral nutrient in containerized crop production that is necessary for crop growth and development. Due to production aspects, the N added to crops far exceeds the amount that the plant uses and such inefficiency results in adverse environmental impacts related to N gaseous and aqueous emissions from containers on the production site. Growers are responsible for optimizing nutrient usage in crop production. Three studies were conducted to investigate and better understand the fate of applied N fertilizers, the transformations associated with individual N sources, and the influence of substrate texture on losses of aqueous and gaseous N species. The first study conducted a mass balance looking at the four major avenues of N fate in an open-air container production setting (plant uptake, immobilized or bound N in a pine bark substrate, leached aqueous N, and gaseous emissions of N), the mass balance was speciated to measure applied and intermediary forms of N fertilizer species to provide insight into the overall fate of applied N. Show Off® Forsythia ×intermedia' Mindor' were grown using two control-release fertilizer (CRF) treatments [AN (ammonium-nitrate based) or UAN (urea ammonium-nitrate)] products. This study determined that 97% of the released N from the CRF treatments was lost via aqueous or gaseous pathways. The aqueous losses were inferred to be predominately composed of NO3-N, while the gaseous emissions were inferred to be predominately lost as inert nitrogen gas (N2). During a second experiment, individual N sources treatments [urea (CH4N2O), ammonium (NH4+), and nitrate (NO3-)] were applied to established containers of At LastⓇ Rosa x 'HORCOGJIL' grown in a pine bark substrate in either open wall high tunnel or a glass greenhouse to determine subsequent reaction sequence and fate based on applied N source. By applying an individual form of N it was determined that based on the N source applied, a sequential set of reactions occurs based on the N source. This study determined that the reactive N gaseous species occurred from the hydrolysis of CH4N2O-N to NH4+ and the nitrification of NH4+ to NO3- and then the denitrification of NO3- to N2. Hibiscus moscheutos' Vintage wine' was grown in either a coarse or fine texture substrate utilizing either a water-soluble fertilizer or a CRF to compare the influence of pine bark texture on N leachate losses and RN gaseous emissions. There were few differences between the two substrate texture treatments related to aqueous or gaseous N losses. In both experiments, the Hibiscus grown in the fine texture substrate resulted in higher above and below-ground biomass at experimental termination. Working with growers to develop best management practices will help to improve the use of N fertilizers and impact growers economically, while simultaneously reducing losses leading to less environmental impact on the areas surrounding production sites. / Doctor of Philosophy / Nitrogen (N) fertilizer is a crucial mineral nutrient input to produce container crops, however excessive application can have detrimental effects on the environment including gaseous N emissions and N leaching leading to water pollution. Therefore, three studies were conducted to investigate N losses during production and potential mitigation strategies using common management practices in the production of container crops. During the first study investigating how N fertilizer is lost from production, results showed that a significant portion of the N added to the containers is either emitted from the containers into the atmosphere or leached from the container. Only a small fraction of the applied N was utilized by the plants for growth and development. The second study investigated the reactions and transformations of different N fertilizers sources. When applying single N sources urea (CH4N2O), ammonium (NH4+), or nitrate (NO3-) result in a set of sequential reactions that occur based on the applied N source. Urea is hydrolyzed via CH4N2O hydrolysis leading to the formation of NH4+ which is nitrified via nitrification to NO3- which is denitrified via denitrification leading to the production of N2 gas. In the final study two pine bark substrate classes were compared when using either a water-soluble fertilizer (WSF) or a controlled-release fertilizer (CRF). Surprisingly there were only a few differences between the two substrate treatments in either the WSF or CRF studies. This body of work show the importance of investigating N fertilizer usage in container crop production. Collaboration between researchers and growers is crucial to develop management practices that maximize the associated economic input of N fertilizers and minimize losses of N that are detrimental to the environment.

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Soilless production of crops relies on the addition of high concentrations of nutrients with the irrigation water. The drained nutrient solution should be re-used to reduce the risk of pollution and to increase the water- and nutrient use efficiency of the system. Besides the risk of pathogen build-up, one of the main impediments of a wider application of this method is the frequent analysis required to maintain optimum nutrient concentrations and ratios in the rootzone. Yield reductions may be caused by an unbalanced nutrient solution. Alternatively the addition level of nutrients can be calculated through the use of nutrient uptake models that simulate the change in the re-circulated nutrient solution. To simulate crop water and nutrient demand necessary for model based regulation it was necessary to quantify the key factors affecting nutrient uptake by plants. The nutrient solution concentration and ratios between the macro-nutrients affected the uptake of water and nutrients. The total nutrient uptake per root dry weight increased and more specifically the nitrate (NO3 -), phosphate (H2PO4 -), potassium (K+) and sulphate (SO4 2-) uptake increased with an increase in nutrient solution electrical conductivity (EC) from 0.8 to 4.0 mS cm-1 while water uptake decreased. Except for Ca2+ uptake there was no correlation between nutrient and water uptake. Nutrient uptake can thus not be calculated based on water uptake. Instead a mechanistic high-affinity Michaelis-Menten based model can be used to estimate macro-nutrient uptake (Un, mg m-2 hr-1). Water and nutrient uptake was also affected by the solar radiation levels. Since nutrient uptake is related to the growth rate, solar radiation levels can be expected to influence nutrient uptake. The uptake of all ions increased with an increase in the solar radiation levels and for NO3 -, K+ and H2PO4 - the uptake rate was higher at higher nutrient solution concentrations. The Michaelis-Menten based model was adjusted to incorporate the effect of solar radiation levels on nutrient uptake. Water uptake (Wu, L m-2 day-1) was simulated as a function of crop transpiration and crop leaf area using a linear regression model, but since leaf area development was affected by solar radiation levels this was additionally incorporated into the estimation of the leaf area index (LAI). The composition of the nutrient solution also affected the biomass allocation of the crop which can again affect nutrient use as well as the fruit yield. There was also a direct effect of nutrient solution composition on fruit yield and quality with higher EC’s resulting in smaller fruit but an increase in fruit dry matter %, total soluble solids (TSS), titratable acidity (TA) and lycopene content. The results in this thesis make a valuable contribution to our understanding of the effect of nutrient availability (concentration and ratios) and nutrient requirement for growth (solar radiation levels) on nutrient uptake. Incorporating these into nutrient uptake models resulted in the development of a handy tool to simulate changes in composition of re-circulating nutrient solutions ultimately resulting in an improvement of the water and nutrient use efficiency of soilless systems. / AFRIKAANSE OPSOMMING: Die grondlose verbouing van gewasse is afhanklik van toediening van voedingselemente teen hoë peile in die besproeiingswater. Die voedingsoplossing wat dreineer moet hergebruik word om die risiko van besoedeling te verminder en ook om die water en nutriënt verbruik doeltreffendheid van die sisteem te verbeter. ʼn Ongebalanseerde voedingsoplossing kan ʼn verlaging in opbrengste veroorsaak. Benewens die risiko van patogene wat opbou, is die gereelde analises nodig word vir die handhawing van optimale nutriënt konsentrasies en verhouding tussen elemente in die wortelsone een van die hoof faktore wat ʼn meer algemene gebruik van die metode verhoed. Alternatiewelik kan die nutriënt toedieningspeile bereken word deur voedingstof opname modelle en simulasie van die verandering in water en nutriente wat dreineer. Om ʼn model gebaseerde reguleringsmetode daar te stel was dit nodig om die belangrikste faktore wat nutriënt opname beïnvloed te kwantifiseer. Beide die konsentrasie van die voedingsoplossing en die verhouding tussen elemente het ‘n effek gehad op die opname van water en nutriënte. Die totale nutriënt opname per wortel droë massa het toegeneem. Terwyl water opname afgeneem het met ‘n toename in die elektriese geleding (EG) van die voedingsoplossing vanaf 0.8 tot 4.0 mS cm-1 het die nitraat (NO3 -), fosfaat (H2PO4 -), kalium (K+) en sulfaat (SO4 2-) opname verhoog. Behalwe vir Ca2+ opname was daar geen korrelasie tussen water en nutriënt opname nie. Nutriënt opname kan dus nie bepaal word gebaseer op wateropname nie. Alternatiewelik is die gebruik van ʼn meganistiese hoë-affiniteit Michaelis-Menten-gebaseerde model voorgestel om die opname van makro-nutriente (Un, mg m-2 hr-1) te bepaal. Water- en voedingstofopname is beinvloed deur die ligintensiteit vlakke. Voedingsopname word bepaal deur die groei van die plant, daarom is dit verwag dat ligintensiteit vlakke die opname van voedingstowwe sal beïnvloed. Die opname van al die ione het toegeneem met 'n toename in die ligintensiteit vlakke en die tempo van NO3 -, K+ en H2PO4 - opname was hoër by 'n hoër voedingsoplossing konsentrasie. Die Michaelis-Menten gebaseerde model is aangepas om die effek van ligintensiteit vlakke op nutriënt opname te inkorporeer. Opname van water (Wu, L m-2 dag-1) is gesimuleer as 'n funksie van transpirasie en blaaroppervlakte met behulp van 'n lineêre regressiemodel en aangesien die blaaroppervlak ontwikkeling ook deur ligintensiteit vlakke beïnvloed word, is dit opgeneem in die skatting van die blaaroppervlakte-indeks (LAI). Die samestelling van die voedingsoplossing het die biomassa verspreiding beïnvloed. Dit kan nutriënt gebruik en vrug opbrengs beïnvloed. Die voedingsoplossing samestelling het vrug opbrengs en - kwaliteit beinvloed met kleiner vrugte, maar 'n toename in droëmateriaal %, totale oplosbare vastestowwe (TOVS), titreerbare suur (TA) en likopeen inhoud by ʼn hoër EG. Die resultate in hierdie tesis lewer 'n waardevolle bydrae tot ons begrip van die effek van nutriënt beskikbaarheid (konsentrasie en verhoudings) en voedingstof behoefte vir groei (ligintensiteit vlakke) op voedingsopname. Deur die inligting te inkorporeer in voedingsopname modelle het gelei tot die ontwikkeling van 'n handige instrument om die veranderinge in die samestelling van hersirkulerende voedingsoplossings te simuleer. Dit lei gevolglik tot die verbetering van die water en voedingstof gebruik doeltreffendheid van grondlose stelsels.

A degradação ambiental dos últimos anos tem motivado a preocupação a respeito da sustentabilidade das atividades humanas. O manejo inadequado da irrigação e adubação, e baixas precipitações, para lixiviar o excesso de sais aplicados via água de irrigação, podem acarretar a salinização dos solos. A hidroponia se constitui em uma alternativa, para a conservação do solo e preservação dos mananciais de água. A rúcula (Eruca sativa Mill) foi a cultura escolhida para este estudo, pois a sua produção vem se destacando entre as hortaliças. O presente trabalho teve por objetivo determinar a tolerância da rúcula à salinidade da solução nutritiva. O experimento foi conduzido em ambiente protegido localizado na área experimental do Setor de Hidráulica do Departamento de Engenharia Rural da Escola Superior de Agricultura Luiz de Queiroz - ESALQ/USP, no município de Piracicaba-SP. O delineamento experimental foi blocos ao acaso. Avaliaram-se nove níveis de salinidade obtidos com a adição de NaCl sendo estes 1,8; 3,5; 4,5; 5,5; 6,5; 7,5; 8,5; 9,5; 10,5 dS m-1. Os resultado obtidos demonstram que o aumento nos níveis de salinidade proporcionou redução em todos os parâmetros avaliados, exceto o número de folhas que não sofreu influência significativa e a relação raiz/parte aérea foi influenciada de forma crescente. A salinidade limiar encontrada foi de 2,57 dS m-1, com redução de 5,57% na produção para cada aumento unitário na salinidade. A cultura da rúcula foi classificada, como moderadamente sensível à salinidade. É possível obter produções satisfatórias utilizando águas salinas no cultivo hidropônico da rúcula. / The environmental degradation in recent years has motivated the concern about the sustainability of human activities. The inadequate management of irrigation and low rainfall fertilization, to leach the excess salts applied through irrigation water, can lead to soil salinization. Hydroponics constitutes an alternative to soil conservation and preservation of water sources. The rocket (Eruca sativa Mill) was the culture chosen for this study because its production has been increasing among the vegetables. This study aimed to determine the tolerance of the rocket to the salinity of the nutrient solution. The experiment was carried out in protected enviroment on the experimental area of the Hydraulics Section of the University of São Paulo (ESALQ/USP), Piracicaba, State of São Paulo, Brazil. The experimental design was randomized blocks. It were evaluated nine levels of salinity obtained with the addition of NaCl and these 1.8, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5, 9.5, 10.5 dS m-1. The results obtained show that the increased levels of salinity caused a reduction in all parameters except the number of leaves was not affected and the ratio root/shoot was influenced incrementally. The salinity threshold was found to be 2.57 dS m-1, a reduction of 5.57% in production for each unit increase in salinity. The rocket press was classified as moderately sensitive to salinity. It is possible to obtain satisfactory production using saline water for hydroponic cultivation rocket press.