Tatiane Ohland

Directed-spray application of paraquat and diuron in physic nut plants

There is little information about the selectivity of herbicides in physic nut (Jatropha curcas) in Brazil. Therefore, this study aimed to evaluate the selectivity of different doses and mixtures of paraquat and diuron in direted-spray applications in physic nut plants in greenhouse conditions. The study used a randomized block design, with five replicates. The treatments were: paraquat (200 and 600 g ha-1), diuron (1,000 and 2,000 g ha-1), paraquat + diuron (200 + 1,000 g ha-1), paraquat + diuron (200 + 2,000 g ha-1), paraquat + diuron (600 + 1,000 g ha-1), paraquat + diuron (600 + 2,000 g ha-1) and a control (no application). Directed-spray application was performed at 70 days after sowing by the lower third of the plants. The treatments of diuron and paraquat + diuron mixtures affected the growth and photosynthetic activity of physic nut plants, injuries being more pronounced at doses of diuron of 2,000 g ha‑1, while the isolated application of paraquat at doses of 200 and 600 g ha-1 showed good selectivity potential for physic nut plants.

Spacing, population density and nitrogen fertilization in corn grown in an Oxisoil

The objective of this study was to evaluate yield components, leaf nitrogen content and grain yield in corn as affected by row spacing, plant density and nitrogen topdressing. The experiment was conducted with the singlecross hybrid AG 8021, in the municipality of Toledo-PR, in an Oxisoil under no-tillage system, in the crop year 2005/ 2006. The experiment was arranged in a randomized block design and treatments in split-split-plots, with four replications. The two row spacings (0.45 and 0.90 m) were allocated in the main plots, the two plant densities (60,000 and 80,000 plants ha -1 ) were allocated in the subplots and the three nitrogen rates (80, 100, 120 and 140 kg ha -1 N) were allocated in the sub-subplots. Topdress nitrogen was applied using urea as N source. The rise of the plant population from 60,000 to 80,000 plants ha -1 and the application of topdress nitrogen resulted in increased production components. The application of topdress fertilization provided increase in leaf N content and grain yield for the spacings 0.45 m and 0.90 m. Yield was higher in the spacing 0.45 m than 0.90 m. Yield was higher with 60,000 plants than with 80,000 plants at 0.90 m, while at 0.45 m there was no dif ference in relation to the plant density .

Influência da densidade do solo no desenvolvimento inicial do pinhão-manso cultivado em Latossolo Vermelho eutroférrico

Influence of soil density on the early growth of Jatrophacurcas L. cultivated in Oxisol The objective of this work was to evaluate theinfluence of soil densities on the early growth ofthephysic nut(JatrophacurcasL.). The experiment wascarried out in 10.6 dm 3 pots in a greenhouse.The soilused in the experiment wasa clay-texture Oxisolcollected in Marechal Cândido Rondon, Parana State, Brazil. The experimental designwas randomized blockswith five levels ofsoil density (1.08, 1.22, 1.36, 1.50and 1.64kg dm -3 ) with four repetitions. Biometric and plant tissue evaluations were performed 120 days after plant emergence.It was found a reduction by 25% in plant heightat a density of1.64kg dm -3 when compared todensity of1.08kg dm -3 . For root length, the reduction was approximately 24%, 35%, 54% and 66%at the densities of1.22,1.36,1.50 and1.64 kg dm -3 ,

Enraizamento de estacas apicais de figueira Roxo de Valinhos submetidas à estratificação a frio úmido e AIB

Na producao de mudas de figueira a utilizacao de estacas apicais de menor comprimento pode facilitar o manejo no viveiro, entretanto ainda nao foram definidos os protocolos para enraizamento desse tipo de estaca. O objetivo do presente trabalho foi avaliar a acao da estratificacao a frio umido e do tratamento com AIB na rizogenese de estacas apicais de figueira Roxo de Valinhos. As estacas foram coletadas da porcao apical dos ramos no final do periodo hibernal (julho) e padronizadas com 20 cm de comprimento e diâmetro aproximado de 0,7 cm. As estacas foram estratificadas (estacas embrulhadas em jornal umedecido e protegidas com saco plastico a temperatura de 4 oC, em câmara tipo BOD) por diferentes periodos (0, 15, 30, 45 e 60 dias) e, posteriormente, tratadas e nao tratadas com 2.000 mg L-1 de AIB por 10 segundos. Em seguida, as estacas foram enterradas em leito de areia umedecido sob telado constituido de tela de polipropileno preta (sombreamento de 50%). Passados 60 dias de cada periodo de estratificacao, foram mensuradas a percentagem de estacas enraizadas, a percentagem de estacas brotadas e o numero medio de brotacoes e de raizes por estaca. Conclue-se que as estacas apicais de figueira Roxo de Valinhos estratificadas a frio umido por 30 dias e posteriormente tratadas com 2.000 mg L-1 de AIB apresentaram maior potencial de rizogenese.