The production of vegetables in communities of family farmers in semiarid regions is limited due to rudimentary cultivation practices and systems, water scarcity, and excess salts in the water and soil. Thus, the objective of this work was to evaluate the production of rocket (Eruca sativa L. cv. Folha Larga) in a low cost hydroponic system, considering strategies for the use of brackish water in the nutrient solution. The experiments were conducted in complete randomized designs, in 6×2 factorial arrangements, with five replications, using rocket plants grown in different nutrient solutions, consisting of six salinity levels (1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 dS m -1) and two circulation frequencies of the nutrient solution (twice a day, at 8:00h, and 16:00h; and three times a day, at 8:00h, 12:00h, and 16:00h). In Experiment I, the nutrient solution lost by evapotranspiration was replenished with the respective brackish water used in its preparation; and in Experiment II it was replenished with public water (0.12 dS m -1). The shoot and root fresh and dry biomass of the plants and their respective dry weight proportions, and biometric variables were evaluated. Replenishing of the nutrient solution with public water resulted in lower losses in biomass and plant growth. The increases in circulation frequency of the nutrient solution did not affect the biometric variables, however, the plants prioritized shoot biomass development to the detriment of the root when using high circulation frequencies.

The need to use strategies for using brackish water in agriculture, especially in semi-arid conditions, is evident. Based on this information, this study was developed with the aim of evaluating the consumption, efficiency and water content, as well as the dry mass of the arugula plants (cv. Broad Leaf) exposed to brackish nutrient solutions as a function of replacement strategies and circulation frequencies. The treatments consisted of six salinity levels of the nutrient solution (1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 dS m-1) and two circulation frequencies (twice a day 8 a.m. and 4 p.m., and three times a day at 8 a.m., 12 p.m. and 5 p.m.). In Experiment I, the evapotranspiration line was replaced with the respective brackish water used in the preparation of the solution, and in Experiment II, the water supply was used. In both treatments, the experimental design was completely randomized, in a 6 x 2 factorial scheme, with five replications. The conclusion is that it is technically feasible to circulate the nutrient solution twice a day and there were lower losses in the water relations, in the biomass production of the shoot and in the partition of photoassimilates when the replacement with water supply was adopted.

FATORES ABIÓTICOS E A DISTRIBUIÇÃO DE FOTOASSIMILADOS DA MAMONEIRA EM CONDIÇÕES SEMIÁRIDAS1     ALLAN NUNES ALVES2; HANS RAJ GHEYI3; JOSÉ AMILTON SANTOS JÚNIOR4; FREDERICO ANTÔNIO LOUREIRO SOARES5; CLAUDIO AUGUSTO UYEDA6 E JOSÉ EUSTÁQUIO CAMPOS JÚNIOR4   1Artigo extraído da Tese de Doutorado do primeiro autor, presentada ao programa de Pós-Graduação em Engenharia Agrícola da UFCG 2Universidade Federal de Campina Grande. R. Aprígio Veloso, 882 - Universitário, Campina Grande - PB, 58429-900. allan_1nunes@yahoo.com.br 3Universidade Federal do Recôncavo da Bahia. Cruz das Almas - BA, 44380-000. hans@pq.cnpq.br 4Universidade Federal Rural de Pernambuco. R. Manuel de Medeiros, s/n - Dois Irmãos, Recife - PE, 52171-900 eng.amiltonjr@hotmail.com; camposjr.agro@gmail.com 5Instituto Federal Goiano. Rodovia Sul Goiana, Km 01, Zona Rural, Rio Verde – GO, 75.901-970 fredalsoares@hotmail.com 6Instituto Federal de Pernambuco, Vitória de Santo Antão. Propriedade Terra Preta Zona Rural, s/n, Vitória de Santo Antão - PE, 55600-000 cauyeda@yahoo.com.br     1 RESUMO   Embora a susceptibilidade a fatores abióticos seja evidente, a análise dos fotoassimilados em plantas sob estresse é relevante para subsidiar práticas de manejo. Nesta direção, buscou-se avaliar a produção da biomassa e analisar a distribuição de fotoassimilados da mamoneira (BRS Energia) irrigada com águas salinas (CEa = 0,6; 1,6; 2,6; 3,6; e 4,6 dS m-1) e adubada com doses de nitrogênio (50; 75; 100, 125 a 150 mg kg-1 de solo). Os fatores testados foram alocados em blocos casualizados, em esquema fatorial 5x5, com três repetições, totalizando 75 unidades experimentais. Os dados obtidos foram submetidos à análise da variância pelo teste ‘F’ e comparados mediante análise de regressão em 0,01 nível de probabilidade. Verificou-se que até CEa = 3,6 dS m-1 houve maior produção de massa seca da parte aérea sob 125 mg de N kg-1 de solo e que nas condições de salinidade impostas às plantas, as folhas foram a maior fonte e o racemo o maior dreno da parte aérea, bem como a alocação de fotoassimilados na raiz foi até 59,75% maior que na parte aérea.   Palavras-chave: Ricinus communis L., salinidade, adubação nitrogenada     ALVES, A. N.; GHEYI,H. R.; SANTOS JÚNIOR, J. A.; SOARES, F. A. L.; UYEDA, C. A; CAMPOS JÚNIOR, J. E. ABIOTIC FACTORS AND DISTRIBUTION OF PHOTOASSIMILATES IN CASTOR BEAN PLANTS UNDER SEMIARID CONDITIONS       2 ABSTRACT   Although the susceptibility to abiotic factors is obvious, the analysis of photoassimilates in plants under stress is relevant to subsidize management practices. In this context, the production of biomass and partition of photoassimilates of castor bean (BRS Energy) irrigated with saline water (ECw = 0.6, 1.6, 2.6, 3.6, and 4.6 dS m -1) and fertilized with nitrogen (50; 75; 100, 125 to 150 mg kg-1 of soil) was evaluated. The factors tested were allocated in randomized blocks in a 5x5 factorial design with three replications, totaling 75 experimental units, and the data were submitted to analysis of variance by the ‘F’ test and compared by regression analysis at 0.01 level of probability. It was verified that up to ECw = 3.6 dS m-1 there was greater dry mass production of shoot under 125 mg of N kg-1 of soil. In the conditions of salinity imposed to the plants, leaves were the greater source and racemus was the greater drainage of the aerial part, as well as the allocation of photoassimilates in the root was up to 59.75% higher than in the aerial part.   Keywords: Ricinus communis L., salinity, nitrogen fertilization

The demands of high-quality zucchini fruits by the consumer market make studies regarding the improvement of cultivation systems, such as plant nutrition and salinity tolerance. Considering the demands of the consumer market for the high quality of zucchini fruits, it is necessary studies regarding the improvement of production systems for this improvement, such as nutrition and salinity tolerance to plant. Thus, this study aimed to evaluate the zucchini fruits quality characteristics, grown in soilless, under N:K ratios, and levels of electrical conductivity of the nutrient solution. The experiment was conducted in a protected environment in pots with 8.2 dm³ of volumetric capacity filled with commercial substrate. The trial design adopted was randomized blocks, with three replicates, in a 5x3 factorial scheme, with five levels of electrical conductivity (1.0; 2.0; 3.0; 4.0; and 5.0 dS m -1 ) and three N:K ratios (2:1; 1:1; and 1:2), both in the nutrient solution. The application of the nutrient solution was by fertigation through drip irrigation. Throughout the experiment, variables related to fruit quality and total plant biomass production were analyzed. The HIGHLIGHTS• Electrical conductivity (EC) and N:K ratios modify zucchini fruit size.• Organoleptic characteristics of zucchini fruits increase with EC.• Total dry mass production of plants showed interaction between N:K ratio and EC.

Resumo:A utilização da hidroponia tem sido considerada como uma alternativa aos sistemas de produção agrícola, especialmente na produção de hortaliças, frente a problemas de salinidade em regiões semiáridas.Diante disso, o objetivo do trabalho foi analisar aspectos da produção de fitomassa fresca da parte aérea (FFPA) e da raiz (FFR), tal qual, a fitomassa fresca e seca da raíz (FFR e FSR, respectivamente)em plantas de rúcula (cv. Folha larga) em hidroponia de baixo custo.Dois experimentos foram desenvolvidos em ambiente protegido (casa de vegetação), no Departamento de Engenharia Agrícola da Universidade Federal de Pernambuco -DEAGRI/UFRPE, em Recife-PE. Os tratamentos consistiram em seis níveis de salinidade da solução nutritiva (1,5; 3,0; 4,5; 6,0; 7,5 e 9,0dS m -1 ) e duas frequências de circulação (duas vezes ao dia -às 8 e às 16 horas; e três vezes ao dia -às 8, 12 e 16 horas). No experimento I, a reposição da lâmina evapotranspirada foi efetuada com água salobra, e no experimento II, com água de abastecimento (0,12 dS m -1 ). Em ambos os experimentos, o delineamento experimental foi o inteiramente casualizado, em esquema fatorial 6 x 2, com cinco repetições.Concluiu-se que em ambas as estratégias de reposição da solução nutritiva, a salinidade da solução nutritiva ocasionou decréscimo na fitomassa fresca e seca da parte aérea e raiz, no entanto, verificou-se que o aumento da frequência de circulação da solução nutritiva para três vezes ao dia proporcionou melhores resultados na fitomassa fresca e seca da raiz e, nos níveis mais salinos, sobre a fitomassa fresca da parte aérea.Palavras-Chave:Água salobra, hidroponia, rúcula. IntroduçãoA rúcula (Eruca sativa) também chama de mostarda persa, é uma hortaliça herbácea, pertencente à família das Brassicáceaes, originária da região Mediterrânea e oeste da Ásia; apresenta folhas alongadas e pode medir entre 10 a 15 centímetros de altura (OLIVEIRA et al., 2012;JARDINA et al., 2017) e, por apresentar crescimento rápido e ser de fácil cultivo em canteiros, a rúcula é uma ótima opção para pequenos produtores (BORGES et al., 2014). 1 Agrônomo, Mestre em Engenharia Agrícola -PGEA/UFRPE, camposjr

Sensibilidade à obstrução por partículas sólidas de emissores contínuos integrados à fita gotejadora / José Eustáquio Campos Júnior. --versão revisada de acordo com a Resolução CoPGr 6018 de 2011. --Piracicaba, 2022. 107 p.Tese (Doutorado) --USP / Escola Superior de Agricultura "Luiz de Queiroz".1. Partículas minerais 2. Sedimentação de partículas 3. Irrigação localizada 4. Antiobstrução I. Título

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The study aimed to assess the yield, nutrients accumulation and fruit quality of watermelon grown under different NPK rates provided by mineral and organic fertilizers. The experiment was performed at the Federal University of Campina Grande (UFCG), Campus Pombal-PB, during the period from June to September 2013. Treatments consisted of three nutrient concentrations N, P and K (50, 100 and 150% of NPK recommendation for watermelon) and five ratios of mineral and organic fertilizer (100/0, 75/25, 50/50, 25 / 75 to 0/100). The experimental design was in randomized blocks, in a 3x5 factorial scheme with four replicates. The NPK rate corresponding to 100% was 120 kg ha-1 respectively for N, P and K. The following variables were evaluated: fruit yield, nutrient accumulation, titratable acidity, soluble solids and ratio between soluble solids and titratable acidity. The concentration of 150% of nutrients was more effective in increasing the yield for the 75/25, 25/75 and 0/100 ratios of mineral and organic fertilizers, and the concentrations of 100 and 150% were the most effective in the accumulation of soluble solids when applied in the mineral and organic fertilizer ratios of 75/25 and 50/50.