<p>Irrigation with saline waters is an agricultural practicethat is becoming increasingly common as competition for freshwater increases. In this thesis the mechanisms behind salinityand drought stress has been studied using data from fieldexperiments in combination with a modelling tool, theCoupModel. Measurements from field experiments on salinity,boron toxicity and drought stressed tomatoes grown during twoclimatically different seasons in the Arava desert, Israel,showed a linear relationship between relative growth andevapotranspiration, for all treatments and seasons. Data fromthe spring was used to concurrently simulate growth andtranspiration, hence accounting for feedback mechanisms betweenthe plant and the environment. Salinity stress was modelled asan osmotic effect (reduction of water uptake at high soilsalinities, W approach) or a toxicity effect (direct reductionof photosynthesis with soil salinity, G approach). Goodagreement between simulated growth and transpiration wasachieved with both salinity stress approaches, with twoexceptions. When growth and transpiration were simulated withthe W approach at different salinity levels, transpiration wasunderestimated at high stress. The G approach resulted in anunderestimation of growth at high water stress under moderatesalinity. A direct decrease of photosynthesis leads to adecreasing water-use efficiency with salinity while water-useefficiency remains constant with salinity when the salinitystress is modelled as a reduction in water uptake. Measurementsshowed decreasing water-use efficiency for the salinitygradient, explaining why the W approach was not applicable. Itwas not possible to detect any considerable differences betweenthree different approaches for water uptake tested in thestudy.</p><p><b>Keywords:</b>Water-use efficiency; osmotic effect; iontoxicity; semi-arid.</p>

Irrigation with saline waters is an agricultural practicethat is becoming increasingly common as competition for freshwater increases. In this thesis the mechanisms behind salinityand drought stress has been studied using data from fieldexperiments in combination with a modelling tool, theCoupModel. Measurements from field experiments on salinity,boron toxicity and drought stressed tomatoes grown during twoclimatically different seasons in the Arava desert, Israel,showed a linear relationship between relative growth andevapotranspiration, for all treatments and seasons. Data fromthe spring was used to concurrently simulate growth andtranspiration, hence accounting for feedback mechanisms betweenthe plant and the environment. Salinity stress was modelled asan osmotic effect (reduction of water uptake at high soilsalinities, W approach) or a toxicity effect (direct reductionof photosynthesis with soil salinity, G approach). Goodagreement between simulated growth and transpiration wasachieved with both salinity stress approaches, with twoexceptions. When growth and transpiration were simulated withthe W approach at different salinity levels, transpiration wasunderestimated at high stress. The G approach resulted in anunderestimation of growth at high water stress under moderatesalinity. A direct decrease of photosynthesis leads to adecreasing water-use efficiency with salinity while water-useefficiency remains constant with salinity when the salinitystress is modelled as a reduction in water uptake. Measurementsshowed decreasing water-use efficiency for the salinitygradient, explaining why the W approach was not applicable. Itwas not possible to detect any considerable differences betweenthree different approaches for water uptake tested in thestudy. <b>Keywords:</b>Water-use efficiency; osmotic effect; iontoxicity; semi-arid. / NR 20140805

Submitted by Deyse Queiroz (deysequeirozz@hotmail.com) on 2018-05-17T18:29:46Z No. of bitstreams: 1 EVANDRO MANOEL DA SILVA - DISSERTAÇÃO PPGHT 2015..pdf: 1720647 bytes, checksum: fb6de435827bffd8e625269180f250e8 (MD5) / Made available in DSpace on 2018-05-17T18:29:46Z (GMT). No. of bitstreams: 1 EVANDRO MANOEL DA SILVA - DISSERTAÇÃO PPGHT 2015..pdf: 1720647 bytes, checksum: fb6de435827bffd8e625269180f250e8 (MD5) Previous issue date: 2015 / O cultivo da goiabeira nas áreas irrigadas do semiárido do nordeste brasileiro tem grande importância socioeconômica. Sobretudo, devido à limitação de água de qualidade para irrigação nesta região, é necessário o estudo de técnicas que viabilizem o uso de água salina no cultivo da espécie. Nesse sentido, objetivou-se com esse trabalho avaliar a tolerância de porta-enxerto de goiabeira ao aumento da salinidade na água de irrigação, sob adubação com distintas doses de nitrogênio. O experimento foi desenvolvido em casa de vegetação do Centro de Ciências e Tecnologia Agroalimentar da Universidade Federal de Campina Grande (CCTA/UFCG), localizado no município de Pombal – PB. O delineamento experimental foi em blocos casualizados, num esquema fatorial 5 x 4, com os tratamentos referentes à de cinco níveis de condutividade elétrica da água de irrigação (CEa) de 0,3; 1,1; 1,9; 2,7 e 3,5 dS m-1 em interação com quatro doses nitrogênio (N): 70, 100, 130 e 160% de N da dose recomendada para mudas de goiabeira. Utilizaram-se quatro repetições, com duas plantas úteis por unidade experimental, onde se avaliou o genótipo de goiabeira Paluma. Iniciou-se a aplicação dos tratamentos a partir de 25 dias após a emergência de plântulas (DAE). Foram avaliadas as variáveis morfológicas de altura de planta, diâmetro do caule, número de folhas e área foliar aos 130 e 190 DAE, e as fisiológicas referentes à taxa de crescimento absoluto e relativo da altura de planta e do diâmetro do caule nos períodos de 25-130 e 130-190 DAE. As variáveis de fitomassa fresca e seca de caule, folhas e parte aérea, fitomassa seca de raiz, seca total e o índice de qualidade de Dickson foram avaliados aos 190 DAE. O aumento da CEa, a partir de 0,3 dS m-1 afeta negativamente as variáveis morfológicas aos 130 DAE e as fisiológicas no intervalo de 25 à 130 DAE. Aos 190 DAE as variáveis morfológicas e as fitomassas dos porta-enxerto de goiabeira são tolerantes aos níveis de CEa de 2,1 a 2,8 dS m-1. Referente às variáveis fisiológicas no período de 130-190 DAE, a taxa de crescimento relativo da altura de planta é tolerante ao nível de CEa de 3,5 ds m-1 . A dose de 70% de N estimula o crescimento das variáveis morfofisiológicas e a produção de fitomassa dos porta-enxerto de goiabeira nos períodos avaliados, com exceção da altura de plantas aos 130 DAE e suas taxas de crescimento absoluto e relativo de 25-130 DAE, em que os maiores valores são obtidos nas doses de 88 a 100% de N. O uso da adubação nitrogenada nas doses de 100 a 130 e de 70 a 130% de N reduz o efeito da salinidade da água de irrigação sob a fitomassa seca da raiz e o índice de qualidade de Dickson, respectivamente, dos porta-enxerto de goiabeira aos 190 DAE. / The crop of guava at the irrigated areas of the Brazilian semiarid northeast has great socioeconomic importance. Above all, due to limitation quality water for irrigation in this region, it is necessary to study techniques that make feasible the use of saline water in the species of cultivation. In this sense, aim of this work was to evaluate the guava rootstock tolerance to increased salinity in irrigation water, under fertilization with different nitrogen levels. The experiment was developed in greenhouse of the Center for Science and Technology Agrifood the Federal University of Campina Grande (CCTA / UFCG), located in the city of Pombal – PB. The experimental outline was a randomized block in a factorial 5 x 4, with treatments related to the five levels of electrical conductivity of irrigation water (ECw) 0.3; 1.1; 1.9; 2.7 and 3.5 dS m-1 interacting with four nitrogen (N): 70, 100, 130 and 160% N of the recommended dose for guava seedlings. Four replications were used, with two plants per experimental unit, where to evaluate the guava genotype Paluma. Begin the application the treatments from 25 days after seedling emergence (DAE). The morphological variables plant height, stem diameter, number of leaves and leaf area to 130 and 190 DAE, and physiological regarding absolute growth rate and relative plant height and stem diameter were evaluated in periods of 25 -130 and 130-190 DAE. The variables fresh biomass and dry stem, leaves and shoots, root dry biomass, total dry and Dickson quality index were evaluated at 190 DAE. The increase ECw from 0.3 dS m-1 negatively affect the morphologic variables to 130 DAE and physiological in the range of 25 to 130 DAE. At 190 DAE morphological variables and fitomassas of guava rootstocks are tolerant to ECw levels from 2.1 to 2.8 dS m1 . Physiological variables relating to the period of 130-190 DAE, relative growth rate of the height plant is tolerant to ECw level of 3.5 dS m-1 . The dose of 70% of N stimulates the growth of morphophysiological variables and biomass production of guava rootstock in the evaluated periods, with exception of plant height to 130 DAE and its absolute growth rates and relative of 25-130 DAE, where the highest values are obtained at doses of 88-100% of N. The use of nitrogen fertilizer in doses of 100 to 130 and 70-130% N reduces the effect of salinity of irrigation water under root dry biomass and the Dickson quality index, respectively, of guava rootstocks to 190 DAE.

Submitted by Deyse Queiroz (deysequeirozz@hotmail.com) on 2018-05-23T12:48:29Z No. of bitstreams: 1 DANIEL SOARES DE ABRANTES - DISSERTAÇÃO PPGSA PROFISSIONAL 2015..pdf: 4362123 bytes, checksum: 252907e323bf8081a6d7afc2b1361702 (MD5) / Made available in DSpace on 2018-05-23T12:48:29Z (GMT). No. of bitstreams: 1 DANIEL SOARES DE ABRANTES - DISSERTAÇÃO PPGSA PROFISSIONAL 2015..pdf: 4362123 bytes, checksum: 252907e323bf8081a6d7afc2b1361702 (MD5) Previous issue date: 2015 / O cultivo da goiabeira mostra-se como atividade econômica e social importante, visto ser uma das frutas tropicais de maior aceitação no Brasil, entretanto, a disponibilidade de água para a irrigação tem se tornado cada vez mais escassa, tanto em termos de quantidade como de qualidade especialmente, em regiões áridas e semiáridas onde a evaporação é maior que a precipitação. Nesse contexto, o uso de águas salinas na agricultura deve ser considerado como alternativa importante, pois muitas vezes, é a única água disponível ao agricultor. Neste sentido, objetivou-se com esta pesquisa, avaliar a produção de mudas enxertadas de goiabeira irrigadas com águas de distintos níveis salinos e sob doses de adubação nitrogenada. Instalou-se dois experimentos usando em um o porta-enxerto de goiabeira Crioula e no outro o porta enxerto Paluma e, tendo como enxerto, a cv. de goiabeira Paluma. Os distintos experimentos foram instalados em condição de casa de vegetação, do Centro de Ciências e Tecnologia Agroalimentar da Universidade Federal de Campina Grande, Campus de Pombal-PB, usandose o delineamento experimental de blocos casualizados, cujos tratamentos foram distribuídos em esquema fatorial 5 x 4 e quatro repetições, sendo cada parcela constituída por três plantas. Os tratamentos resultaram da combinação entre dois fatores: salinidade da água de irrigação (CEa) em cinco níveis sendo eles S1-0,3; S2-1,1; S3-1,9; S4-2,7 e S5-3,5 dS m-1 preparados mediante adição de cloreto de Na, Ca e Mg, mantendo-se uma proporção equivalente igual a 7:2:1, respectivamente, e quatro doses de nitrogênio N1 - 70%, N2 - 100%, N3 -130% e N4 - 160% da dose padrão (552 mg de N dm-3 ). O aumento da CEa, a partir de 0,3 dS m-1 afeta negativamente as variáveis de crescimento bem como a qualidade das mudas de goiabeira Paluma enxertadas sob os porta-enxertos Paluma e Crioula. Houve interação entre a salinidade da água de irrigação e doses de nitrogênio para o diâmetro do enxerto de goiabeira Paluma, sendo que a dose de 100% de N reduziu o efeito da salinidade da água de irrigação aos 70 DAT. Para as mudas de goiabeira Paluma tendo como porta-enxerto a cv. Crioula, a adubação nitrogenada nas doses 100% e 130% para o IQD, atenuaram os efeitos do estresse salino, obtendo-se os maiores valores sob o nível de CEa de 0,8 e 1,4 dS m-1 respectivamente. As mudas irrigadas com águas de CEa de até 1,9 dS m-1 atenderam os critérios para produção de muda padrão de goiabeira. A utilização de águas com CEa de até 2,2 e 2,0 dS m-1 , na irrigação de mudas de goiabeiras Paluma tendo como porta enxerto a cv. Crioula e cv. Paluma, respectivamente, promovem redução aceitável no crescimento das plantas de 10%. / The cultivation of guava shows up as an important economic and social activity, since it is one of largest acceptance of tropical fruits in Brazil, however, the availability of water for irrigation has become increasingly scarce, both in terms of quantity and quality especially in arid and semi-arid regions where evaporation is greater than precipitation. In this context, the use of saline water in agriculture should be considered as an important alternative because it is often the only water available to the farming community. In this sense, the aim of this research was to evaluate the production of grafted guava plants irrigated with differing levels of saline water and under nitrogen fertilization. He settled on a two experiments using the rootstock of guava Crioula and the other of rootstock and Paluma with the graft, the cv. And Paluma guava. The different experiments were conducted in greenhouse conditions, the Center for Science and Agrifood Technology, Federal University of Campina Grande, Campus de Pombal-PB, using the experimental randomized block design and treatments were distributed in factorial 5 x 4, is 4 replicates, each plot had three plants. The treatments resulted from the combination of two factors: irrigation water salinity (ECw) in five levels S1-0,3; S2- 1,1; S3-1,9; S4-2,7 and S5-3,5 dS m-1 prepared by adding chloride Na, Ca and Mg, maintaining an equivalent ratio equal to 7: 2: 1, respectively, and four nitrogen levels N1 - 70%, N2 - 100%, N3 -130% and N4 - 160% of standard dose (552 mg N dm-3 ). The increase in CEa, from 0,3 dS m-1 negatively affects the growth variables and the quality of Paluma guava plants grafted on rootstocks Paluma and Crioula. There was interaction between water salinity irrigation and nitrogen levels to the diameter of the graft paluma guava, wherein the dose of 100% N reduced the effect of salinity irrigation water at 70 DAT. For guava plants cv Paluma acting as rootstock. Crioula, nitrogen fertilization in doses 100% and 130% for IQD, mitigated the effects of salt stress, obtaining the highest values under ECw level of 0,8 and 1,4 dS m-1 respectively. The seedlings irrigated with ECw of water up to 1,9 dS m-1 met the criteria for the production of standard guava changes. The use of water with supper to 2,2 and 2,0 dS m-1 in irrigation guava seedlings Paluma acting as door graft for cv. Crioula and cv. Paluma respectively, promote acceptable reduction in growth of the plants 10%