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To exploit the full potential of plants, it is essential to provide an adequate water balance during critical growth stages. With knowledge of the substrate’s matric potential, it is possible to realistically measure the amount of water available to the plant. The objective of this research is to study the effect of the matric potential of the substrate on the growth of beans, lettuce, sweet peppers, watermelon, and cauliflower plants. The research goal was to evaluate the effect of the matric potential on the main fertigation parameters of horticultural plants. The plants were cultivated at the University of Almería (Spain) in a controlled chamber in a pot with 250 mL of coconut fiber substrate from block propagation. For treatments T15, T30, T45, and T60, new irrigation was applied when easily available water (EAW) depletion levels of 15, 30, 45, and 60% were reached, respectively. The efficiency of the use of water (WUE), nitrate (NUE), and potassium (KUE) was measured. From T15 to T60, a significant effect was found for the absorption of water, nitrate and potassium, WUE, NUE, and KUE. T60 reduced the plant growth by half. The largest growth was between 15 and 30% of the level of use of EAW. Two different models were constructed according to each plant. It is possible to have a small depletion in the available water and still have plant growth, if there is a balance between the air and water needs of the substrate.

The response of pepper (Capsicum annuum L.) to Ammonium-N was studied in a multispan greenhouse under soilless culture using coir fiber as substrate. Ammonium-N application rates were 0, 2, 4, 6 an...

Recent studies show that vegetables at early stage of development contain higher amounts of phytonutrients and minerals, and lower amounts of nitrates than at fully developed stage. Nevertheless, the effects of some spectrum light on the carotenoid content of lettuce microgreens are unknown. Three different LED lamps were checked: (i) artificial white light (T0); (ii) continuous light-emitting diodes with longer blue-wavelength (T1), and (iii) continuous light-emitting diodes with longer red-wavelength (T2). Different lettuce cvs. were grown under the above described lamps. Plants were collected after 10, 15, 35 and 50 days from planting to produce sprouts, microgreens, initial baby leaf, and baby leaf, respectively. Response to different continuous spectrum lights related to productivity and nitrate content was variable for the different plants. Accumulation of nitrates at initial stages in plant tissues was clearly lower than at final stages of crop development, ranging from 50.2 to 73.4 mg 100 g1 fresh weight for T2. Lettuce consumption is preferable at microgreen stage in comparison with baby leaf stage. Nitrate amounts at microgreen stage were lower than in baby leaf stage, and this content was inversely correlated with carotenoid content, which in tissues was higher at microgreens stage influenced by LED.

Determining nitrogen (N) accumulation and export by common bean as a function of straw and of the splitting of this nutrient is very important, aiming at the management and sustainability of agricultural systems. This study aimed to determine the N accumulation and export by common bean as a function of Zea mays and Urochloa ruziziensis grass straw (maize, maize/U. ruziziensis intercropping and U. ruziziensis) and splitting of top-dressing N fertilization. The experiment was conducted in Jaboticabal-SP-Brazil, during the 2012/13 crop season, in a Red Eutrophic Oxisol (Eutrudox) in no-tillage under irrigation. The experimental design was a randomized block with split plots with four replicates, totaling 120 subplots sized in 25m2 each. The plots consisted of the cropping systems prior to common bean: maize, maize/ U. ruziziensis intercropping and U. ruziziensis. The subplots were composed of ten top-dressing N fertilization splitting schemes (NS) at the phenological stages V3, V4 and R5 in different combinations. Common bean grain yield differs among cropping systems and as a function of top-dressed N split application. U. ruziziensis grass as single crop promotes greater N accumulation in common bean shoots compared to maize and its intercropping with U. ruziziensis grass. Regardless the cropping system, top-dressing N application in a single dose (90 kg ha-1) at V4 leads to similar accumulations and exports to those found in the absence of N fertilization. Splitting schemes with N application at the R5 stage increase the exports of this nutrient by common bean in succession to maize and its intercropping with U. ruziziensis grass. RESUMO Determinar o acúmulo e a exportação de nitrogênio (N) pelo feijoeiro em função da palhada e do seu parcelamento é importante visando o manejo e a sustentabilidade dos sistemas agrícolas. O objetivo com esse trabalho foi determinar o acúmulo e a exportação de N pelo feijoeiro cultivado sob palhada de milho ( Zea mays) e braquiária (Urochloa ruziziensis) exclusivos ou em consórcio e em função do parcelamento da adubação nitrogenada em cobertura. O experimento foi conduzido em Jaboticabal-SP-Brasil, durante a safra 2012/13, num Latossolo Vermelho eutrófico típico, sob área irrigada no sistema plantio direto. O delineamento experimental foi em blocos ao acaso com parcelas subdivididas com quatro repetições, totalizando 120 subparcelas dimensionadas em 25m2 cada. As parcelas foram constituídas pelos sistemas de cultivo antecessores ao feijoeiro: milho, milho consorciado com braquiária e braquiária. As subparcelas foram compostas por dez parcelamentos da adubação nitrogenada de cobertura (PN) estádios fenológicos V 3, V4 e R5 em diferentes combinações. A produtividade de grãos do feijoeiro difere entre os sistemas de cultivo e em função do parcelamento do N em cobertura. O cultivo exclusivo de braquiária proporciona maiores acúmulos de N na parte aérea do feijoeiro comparado ao milho e seu consórcio com braquiária. Independentemente do sistema de cultivo, a aplicação de N em cobertura em dose única de 90 kg ha-1 em V4 (terceiro trifólio) proporciona acúmulos e exportações semelhantes àqueles na ausência da adubação nitrogenada. Os parcelamentos com aplicação de N em cobertura no estádio R5 (pré-florescimento) incrementa as exportações desse nutriente no feijoeiro em sucessão ao milho e seu consórcio com braquiária.

Made available in DSpace on 2018-11-12T17:25:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-06-01. Added 1 bitstream(s) on 2018-11-12T17:34:00Z : No. of bitstreams: 1 S0034-737X2018000300291.pdf: 68075 bytes, checksum: 083ead90bc7efc6e02b30de53bf3e13c (MD5) RESUMO O nematoide das galhas, Meloidogyne enterolobii, é o principal problema fitossanitário para o cultivo da goiabeira. Entre as estratégias para o manejo deste nematoide, as melhores perspectivas estão na identificação ou no desenvolvimento de cultivares ou porta-enxertos resistentes. Buscando elucidar quais plantas poderão ser testadas como porta-enxertos de goiabeira, um experimento foi conduzido em casa de vegetação com o objetivo de avaliar a reação de araçazeiros frente a M. enterolobii. Sete espécies de araçazeiros foram avaliadas (Eugenia stipitata, Psidium acutangulum, P. cattleyanum ‘amarelo’, P. friedrichsthalianum, P. guajava var. minor, P. guineense e Psidium sp.), as quais foram inoculadas com uma suspensão de 3.000 ovos de M. enterolobii, sendo utilizadas plantas de berinjela como tratamento controle. Durante as avaliações, foram determinados a massa fresca de raízes, o número de ovos e juvenis de segundo estádio (J2) por sistema radicular, o fator de reprodução [FR = Pf/Pi] e a reação dos araçazeiros. Os araçazeiros, E. stipitata, P. cattleyanum ‘amarelo’ e P. friedrichsthalianum tiveram fator de reprodução menor que um (FR < 1), sendo, portanto, resistentes a M. enterolobii. Nesses araçazeiros houve bom desenvolvimento do sistema radicular e nas plantas suscetíveis (FR>1) foram observadas muitas galhas, elevado número de ovos e J2 e necroses nas raízes, com a presença de Fusarium solani e Rhizoctonia solani. Os araçazeiros, P. cattleyanum ‘amarelo’, P. friedrichsthalianum e E. stipitata são resistentes ao M. enterolobii e podem ser testados como possíveis porta-enxertos de goiabeira. ABSTRACT Root-knot nematode Meloidogyne enterolobii is the main phytosanitary problem of guava cultivation in Brazil. Among the strategies to manage the problem, the best prospects are in identifying or developing cultivars or rootstocks that are resistant to this nematode. To identify plants with potential as rootstocks for guava, the reaction of araçá (wild guava) to M. enterolobii was assessed in a greenhouse experiment. Seven araçá species were evaluated (Eugenia stipitata, Psidium acutangulum, P. cattleyanum ‘yellow’, P. friedrichsthalianum, P. guajava var. minor, P. guineense, and Psidium sp.). The plants were inoculated with a suspension of 3,000 eggs of M. enterolobii, using eggplant as control treatment. The parameters fresh root mass, number of eggs and second stage juveniles (J2) per root system, the reproduction factor (RF = Pf/Pi), and araçá reaction were determined during the experiment. RF of the araçá species E. stipitata, P. cattleyanum ‘yellow’, and P. friedrichsthalianum was less than one (RP < 1), therefore resistant to M. enterolobii. The araçá trees had good root system development and the susceptible plants showed many root galls, high number of eggs and J2, and Fusarium solani and Rhizoctonia solani root rot. The araçá species, P. cattleyanum ‘yellow’, P. friedrichsthalianum, and E. stipitata are resistant to M. enterolobii and can be tested as potential guava rootstocks. Faculdades do Centro do Paraná Universidade Estadual Paulista Departamento de Produção Vegetal Universidade Estadual Paulista Departamento de Fitossanidade Faculdade Campo Real Universidade Estadual Paulista Departamento de Produção Vegetal Universidade Estadual Paulista Departamento de Fitossanidade

The use of colored shade nets is a method to protect plants from direct solar radiation and optimize the light spectra they transmit. The purpose of this work was to evaluate the photosynthetically active radiation (PAR), the photosynthetically active integrated radiation (IPAR), temperature, relative humidity, growth, production, and fruit quality of Physalis ixocarpa variety Tecozautla, cultivated under nets generating 60% shade in the colors beige, blue, green, red, and black and under a treatment without netting (control group). Different variables were observed: climatic variables, such as radiation, temperature, and relative humidity; growth variables, such as plant height and stem diameter; production variables, such as number, weight, and caliber of the fruit; and quality variables of the fruit, such as pH and total soluble solids. The highest PAR, IPAR, and temperature and lowest relative humidity were obtained in the absence of netting. The white net resulted in the highest PAR and IPAR but no difference in temperature or relative humidity. In addition, an increase in the height, stem diameter, number of branches, and weight, number, and size of the fruit was observed. The white net resulted in the highest yield: 88% higher than in the control group. The pH of the fruit was significantly higher under the white netting, and no differences among the treatments in terms of the content of total soluble solids were found.

An intercrop is studied here as a new way of farming in soilless systems within a protected environment. To estimate the efficiency of intercropping in this cultivation system, an experiment was conducted to evaluate the effect of the electrical conductivity (EC) of the nutrient solution (2.0, 2.5, and 3.0 dS·m−1) on lettuce and tomato plants and on the agronomic and economic feasibility of the intercrop compared with monoculture. The results indicated that a moderate increase in EC from 2.0 to 3.0 dS·m−1 did not exert any important effect on tomato plant production or quality but did cause a decrease in lettuce yield in both the first and second crops. Intercropping was only feasible for lettuce when the tomato and lettuce plants were transplanted on the same day. The highest tomato (G class) and lettuce yields were achieved at an EC of 2.5 dS·m−1; this condition resulted in the highest intercrop profitability (0.53 €·m−2 more) when compared with tomato monoculture.

The intercropping system is characterized by interspecific competition and leads to one of the most limiting abiotic factors for high plant yield in this cropping system. Plants under low light can carry significant weight in physiological parameters that can limit growth. Light is one of the abiotic factors that limits productivity; in the present study, it was hypothesized that tomato (Solanum lycopersicum L.) and lettuce (Lactuca sativa L.) intercropping in different transplanting periods promotes changes in gas exchange, photosynthetic pigments, and biomass accumulation in two lettuce cultivars. An experimental study was carried out in Jaboticabal, Sao Paulo, Brazil. The treatments consisted of a combination of the following factors: lettuce (one ‘Lucy Brown’ plant between two tomato plants and two ‘Vanda’ plants between tomato plants), two cultivation systems (intercropping and monoculture), and four lettuce transplanting periods (0, 7, 14. and 21 d after tomato transplanting). The experiment was a randomized block with a 3 × 2 × 4 factorial design and four replicates. Transpiration and stomatal conductance were reduced in lettuce by insterspersing plants under a monoculture system. Lettuce-tomato intercropping severely reduced photosynthesis, fluorescence, chlorophyll pigment content, and DM accumulation. Therefore, ‘Vanda’ is better than ‘Lucy Brown’ for intercropping with tomato.

RESUMO - Objetivou-se avaliar o efeito direto e indireto de plantas de milho Bt sobre o desenvolvimento e a repro-ducao do predador Podisus nigrispinus (Dallas, 1851) (Hemiptera: Pentatomidae). Os experimentos foram conduzidos na Embrapa Agropecuaria Oeste, em Dourados-MS. Para avaliar o efeito direto, o predador P. nigrispinus foi colocado em contato direto com as plantas de milho Bt e nao Bt e alimentado com pupas de Tenebrio molitor (L.). Para avaliar o efeito indireto, lagartas de Spodoptera frugiperda (Smith) foram colocadas para se alimentarem previamente em plan-tas de milho Bt e nao Bt e depois oferecidas ao predador. Foram avaliados duracao e viabilidade dos periodos ninfais, periodos de pre-oviposicao, de oviposicao, fecundidade e longevidade de adultos (femeas e machos). As plantas de milho Bt, quando em contato direto com P. nigrispinus, nao influenciaram parâmetros biologicos do predador, em com-paracao ao milho convencional. Todavia, foi constatado menor duracao para o segundo instar ninfal de P. nigrispinus, quando este predador foi criado em lagartas de S. frugiperda que haviam sido alimentadas previamente em plantas de milho Bt. De maneira geral, nao ha interferencia na biologia e na capacidade de reproducao das plantas de milho Bt sobre o predador. Palavras-chave: plantas Bt, inimigo natural, sobrevivencia, reproducao, Spodoptera frugiperda. DIRECT AND INDIRECT EFFECTS OF BT CORN ON THE PREDATOR Podisus nigrispinus ABSTRACT - This paper aimed to evaluate the direct and indirect effects of Bt corn on the development and reproduc-tion of the predator Podisus nigrispinus (Dallas, 1851) (Hemiptera: Pentatomidae). The experiments were carried out of the Embrapa Agropecuaria Oeste, in Dourados, Mato Grosso do Sul, Brazil. To evaluate the direct effect of the Bt corn and non-Bt corn, the predator P. nigrispinus was kept in contact with these plants and fed with pupae of Tenebrio molitor (L.). To evaluate the indirect effects of Bt corn and non-Bt corn, larvae of Spodoptera frugiperda (Smith) were fed with these plants and later offered to the predator. Period of nymphal development, nymphal survival, duration of pre-oviposition and oviposition periods, fecundity and longevity of adults (females and males) were evaluated. Bt corn plants, when in direct contact with P. nigrispinus, did not influence biological parameters of the predator, compared to conventional corn. It was observed a lower duration for the second nymphal instar of P. nigrispinus when this predator was created in larvae of S. frugiperda that had previously been fed on Bt corn plants. Overall, there is no interference with biology and reproduction capacity of the Bt corn plants on the predator. Keywords: Bt plants, natural enemy, survival, reproduction, Spodoptera frugiperda.