Hideaki Wilson Takahashi

Level of nitrate in lettuce cultivated in hydroponic and conventional systems

O monitoramento do teor de nitrato nos alimentos e importante, uma vez que poderao ser formados compostos prejudiciais a saude humana e animal apos sua ingestao. Com o objetivo de avaliar o teor de nitrato presente em alface, foram coletadas e analisadas as folhas de alface crespa comercializada no Municipio de Londrina, cultivada em sistemas hidroponico e convencional. Os valores encontrados variaram entre 26 e 2.568 mg.kg-1 de peso fresco, sendo que as plantas cultivadas em sistema hidroponico apresentaram teores superiores em relacao as cultivadas em sistema convencional, porem abaixo do limite maximo de nitrato permitido para alface, na Europa.

Correlações entre caracteres quantitativos em milho pipoca

Knowledge of the size of the association among traits of interest is of fundamental importance in a breeding program to allow genetic progress. The genotypic, phenotypic and environment correlation were studied among quantitative traits of popcorn maize. Nine popcorn maize genotypes were assessed. A randomized complete block design with eight replications was used. The UEL ZP, UEL SI and UEL PAP. genotypes which had greatest expansion capacity (27.50; 27.15 and 24.20, respectively), also had the greatest values for the number of grains per volume (244.75; 248.50 and 248.75, respectively). The expansion capacity correlated positively with the popcorn size and with number of grains per volume and negatively with plant yield. The traits plant yield, and total ear weight showed positive phenotypic and genotypic correlation that permits the choice of the trait that always suits at the breeding objectives.

Hydroponic lettuce yield in differents electrical conductivity

Em cultivos hidroponicos e usual avaliar o teor de nutrientes da solucao nutritiva atraves da condutividade eletrica. Este trabalho teve como objetivo determinar a melhor condutividade eletrica da solucao nutritiva para o cultivo de alface tipo crespa cultivar Veronica. Testaram-se 4 tratamentos que consistiram em diferentes condutividades eletricas da solucao nutritiva. A solucao nutritiva de Hoagland & Arnon (1950) foi utilizada como padrao, da qual realizou-se varias diluicoes ate a obtencao de quantidades ideais de cada nutriente para atingir as diferentes condutividades eletricas: 1,0; 1,5; 2,0; e 3,0 mS cm-1. O delineamento estatistico utilizado foi blocos, com quatro tratamentos e seis repeticoes. A partir dos resultados obtidos pode-se concluir que o tratamento CE = 1,0 mS cm-1 proporcionou boa producao, com concentracoes adequadas de N, P, K, Ca, Mg, S e baixo teor de nitrato, estando abaixo do limite maximo de nitrato permitido para alface, na Europa.

Produção e desenvolvimento da cultura de Physalis L. submetida a diferentes níveis de condutividade elétrica da solução nutritiva

Physalis peruviana L. well known in Colombia and originate in the South American Andes, has attracted some producers in Brazil for producing a fruit with high market value. Since this is a culture adapted to some Brazilian regions, the supply of nutrients is an important aspect that needs to be developed to increase productivity. The study aimed to establish the optimal ranges of concentration of nutrients, using the electrical conductivity of nutrient solution for Physalis. Looking for alternatives to successive cultivations in soil, which cause phytosanitary, environmental and nutritional problems, the experiment was conducted in a greenhouse of the Universidade Estadual de Londrina, Londrina, Parana State in pots containing coarse sand, trickle fertigated. Were analyzed fresh fruit weight, dry weight of leaves, stems and fruit, productivity, soluble solids and total levels of nutrients in the vegetative organs of Physalis. Four treatments were constituted by the electrical conductivity of nutrient solution of 0.5, 1.0, 2.0 and 3.0dS m-1 with five replicates. Significant increases were observed in fruit production and the total contents of N, P, K in some of the evaluated organs (leaves, fruits and stems) when using the higher concentration of nutrients (electrical conductivity) in the nutrient solution.

Composição e manejo da solução nutritiva visando a diminuição do teor de nitrato nas folhas de alface hidropônica

The edible vegetables have a high capacity to accumulate nitrate in the leaves and stem. The excessive consumption of nitrate can be harmful to human health. The best combination of doses and sources of N and supply time were determined in the nutritious solution to reduce the nitrate concentration in cv. Vera leaves of lettuce. The treatments were (T1) 210 mg L-1 of N as nitrate (N-NO3-) from transplantation to harvest; (T2) 189 mg L-1 (90%) of N as nitrate (N-NO3-) associated with 21 mg L-1 (10%) of N as ammonium (N-NH4+); (T3) 210 mg L-1 of nitrate until the 24th day and substitution for 189 mg L-1 of nitrate and 21 mg L-1 N-NH4+ until the end of the cycle; (T4) 210 mg L-1 of N-NO3- until the 24th day of the transplant and reduction to 105 mg L-1 of N-NO3- until the end of the cycle; (T5) 210 mg L-1 of N-NO3- until the 24th day of the transplant and reduction to 52,5 mg L-1 of N-NO3- until the end of the cycle. The best results were obtained with the treatments T2 and T3, with levels of nitrate in the edible part varying from 1,756 to 1,920 mg kg-1 in the fresh matter and equivalent yield to the treatment 1. The reduction of nitrate in nutritious solution in the end of the cycle did not reduce the quantity of nitrate in leaves.

Fertirrigação por gotejamento com doses de K na fase reprodutiva do tomateiro tipo italiano

Tomato is one of the most commercialized vegetables worldwide and its production is limited during some seasons of the year. Studying fertilization management of potassium (K), which is the most extracted nutrient by the tomato crop, could improve its growing conditions as well as its nutritional aspect. We evaluated the effect of K doses, applied by drip fertigation in the early reproductive stage, on productivity and content of K, Ca and Mg for Italian-type tomato under greenhouse conditions. Randomized blocks with ten replications was the experimental design the treatments consistingof five K doses (60, 120, 180, 240 and 300 mg/dm3) applied on the beginning of the reproductive phase. Until flower opening, all plots received the standard nutrient solution. The K doses up to 300 mg/dm3 did not influence the productivity of ripe and wealthy fruits, and the contents of K, Ca and Mg in the diagnostic leaves were not influenced by treatments. On some plants we observed a deficiency of Ca on the second to third bunch. Considering the results in this study, doses of K between 60 and 300 mg/dm3 applied in the phase of highest demand (fruit formation), did not influence the productivity of the Italian-type tomato.

Turboatomizador e repasse com pistola manual na cobertura de pulverização de agrotóxicos em caquizeiro (Diospyros kaki L.f.)

Persimmon crop is growing in importance in Brazil, and with the increase of the production area there also has been an increase in the problems related to diseases and pests. For the control and prevention of these problems, most often it is used pesticides spray, and one of the main techniques is the spray with the aid of air flow. The objective of this study was to evaluate the effects of changes in the application rate and transfer with a spray gun on the leaves mixture coverage. The spraying was performed using tractor and air flow sprayer. The application was performed with two forward speeds of the equipment, leading to different application rates. The transfer was made with a spray gun attached to the same equipment. For the assessment of the coverage it was used a mixture prepared with fluorescent tracer dissolved in water. Leaves were collected in the inside and outside of the tree. Later, in dark room with ultraviolet lighting to highlight the area affected by the fluorescent tracer, the upper and lower surfaces of each leaf were photographed with a digital camera. Each image was subjected to analysis generated by software SIARCS 3.0, resulting in percentage of coverage. It was used a randomized block design with subdivided parcels with four replications, being the treatments in a 2x2x2 factorial scheme (high or low application rate, with or without transfer, inside or outside the tree). The evaluations were made in the upper and lower leaf surfaces. There was significant interaction between treatments (application rate and spray gun transfer), leaf position and surface. High application rate promoted a significant increase in the coverage of the lower leaves, regardless the site in the plant (inside or outside). The inside leaves had a better coverage with the spray gun transfer. As most of the agents of plant damage begin to occur in the lower surface of leaves, it can conclude that the spray gun transfer was more effective to cover the leaves inside the plant than increasing the application rate.

Nutrient concentration in reproductive branches of persimmon

Os estudos de nutricao mineral do caquizeiro, no Brasil, de forma sistematizada, sao inexistentes e bastante escassos, sendo encontrados alguns trabalhos no Japao, Nova Zelândia e Australia. O objetivo deste trabalho foi estudar a nutricao mineral do caquizeiro cultivar Giombo, focalizando o estudo da variacao da concentracao de macronutrientes ao longo dos estadios de desenvolvimento nos orgaos que compoem os ramos frutiferos. O experimento foi conduzido em pomar comercial de caqui, cultivar Giombo, localizado no municipio de Faxina-PR. Os teores foliares de macronutrientes no estadio fenologico recomendado para avaliacao do estado nutricional foram semelhantes aos da Australia e do Japao e continham 20,30; 1,25; 30,55; 23,45; 3,85 e 3,05 g kg-1 de massa seca de N, P, K, Ca, Mg e S, respectivamente.

Nutrients uptake by fruitful branches of persimmon cv. giombo in one cycle of production

A literatura brasileira apresenta poucos dados para subsidiar a recomendacao de adubacao para a cultura do caquizeiro, portanto o objetivo deste trabalho foi estudar o acumulo de massa seca e macronutrientes nos orgaos que compoem o ramo produtivo, ao longo dos estadios fenologicos da cultura de caqui cultivar Giombo e quantificar as necessidades de nutrientes para a producao. O estudo foi realizado em pomar localizado no municipio de Faxinal-PR, e as amostragens de ramos frutiferos foram iniciadas tres semanas apos o inicio da brotacao, repetidas a cada tres semanas, durante 45 semanas. Foram realizadas analises quimicas dos materiais coletados e determinada a extracao de nutrientes ao longo do estadio de desenvolvimento. O total de macronutrientes exportados pela colheita dos frutos foram: 25,47; 5.72; 51.53; 6.76; 2.79 e 5,09, respectivamente, para N, P, K, Ca, Mg e S em kg por ha, para produtividade de 27.7 toneladas por ha de fruto, e os exportados pela retirada de ramos podados para fora do pomar, por questoes fitossanitarias, foram: 2,1; 0,3; 1,1; 5,8; 0,5 e 0,4 kg de N, P, K, Ca, Mg e S em kg por ha.