João Paulo Gonsiorkiewicz Rigon

Caracterização dos níveis de elementos químicos em solo, submetido a diferentes sistemas de uso e manejo, utilizando espectrometria de fluorescência de raios-x por energia dispersiva (EDXRF)

This study aimed to evaluate the chemical elements levels in soil, submitted to different management systems and use by the Energy Dispersive X-Ray Fluorescence Spectrometry - EDXRF. The systems were T1 - agro forestry (SAF), T2 - Native Field (CN), T3 - Native Forest (NM), T4 - Tillage Forest (PF); T5 - conventional tillage system (SPC) and T6 - System tillage (NT). Samples were collected at 0-10 and 10-20 cm, dried and ground for analysis in EDX-720. The soil showed no difference in the average concentrations of chemical elements analyzed in the profiles, but the systems presented different concentrations of metal elements, and T3 had the highest K, Ca and Zn at 0-10 cm and higher contents of K, Ca, Cu, Zn and Mn in the layer of 10-20 cm.

Análise não destrutiva de pigmentos fotossintéticos em folhas de gergelim

Objetivou-se, com o presente trabalho, relacionar pigmentos fotossinteticos extraidos de modo classico em laboratorio com leituras obtidas pelo clorofilometro portatil ClorofiLOG 1030, em folhas de gergelim, por meio de modelos matematicos. O trabalho foi realizado em dezembro de 2010, na Embrapa Algodao, de onde foram retirados discos foliares de gergelim para serem mensurados os indices de clorofila por meio do clorofilometro portatil. Os discos foliares foram submetidos a extracao dos pigmentos fotossinteticos, utilizando-se 5 mL de dimetilsulfoxido (DMSO) e mantidos em banho-maria a 70 oC, durante 30 min; depois foram retirados 3 mL de aliquota para a leitura em espectrofotometro nos comprimentos de onda de 470, 646 e 663 nm. Com base nos resultados analiticos modelos matematicos foram ajustados utilizando-se o indice de clorofila na predicao dos teores de clorofila a, b e total e dos carotenoides e suas relacoes. Concluiu-se que o medidor portatil de clorofila ClorofiLOG 1030 pode ser utilizado na estimativa da concentracao dos pigmentos fotossinteticos em folhas de gergelim com alta precisao, alem de proporcionar economia de recursos e tempo.

Manganese in RR Cotton as Affected by Glyphosate

ABSTRACT There is evidence that glyphosate application in soybean tolerant to herbicides could interfere in the manganese (Mn) nutrition of the crop, but there is no information on this effect in cotton plants. This study aimed at assessing manganese accumulation and distribution in cotton as affected by glyphosate application. The experiment was conducted in nutrient solution with four Mn concentrations and two cotton cultivars: conventional NuOpal and NuOpal tolerant to glyphosate (RR). Glyphosate was applied or not to the tolerant cultivar. The inclusion of the glyphosate resistance gene in cotton and herbicide, application increased shikimic acid (ShA) concentration in the plants. Glyphosate application decreased cotton leaf area and the dry matter production of the plant structures. The adverse effects of glyphosate were not overcome with higher Mn rates in the solution.

Critical phosphorus levels and availability for castor oil plant grown in different soil classes of Brazil

The current study aims to determine critical P levels in different soil classes and their availability for castor bean initial growth. Extraction was done using Mehlich-1 and ion-exchange resin. The experiment was conducted in a greenhouse, in a randomized blocks design with the application of five P doses, which were previously set for each of the four experimental soils (TCo: Chromic Orthic Luvisol; CXbe: Eutrophic Haplic Cambisol; CXve: Typical Eutrophic Cambisol; RY: Fluvic), with four repetitions for 40 days. In the end of the experiment, plants were harvested and shoot dry mass was weighted. At the time plants were collected, samples were gathered to determine soil P availability through Mehlich-1 and ion-exchange resin. Mehlich-1 was more efficient in phosphorus recovery in the following soils: TCo, CXbe and CXve, regardless of applied dose. Critical P levels ranged from 21.33 to 416.64 mg dm due to the clay content in Mehlich-1, and from 30.70 to 177.55 mg dm in resin. MPAC presented positive coefficients regarding soil clay content. The highest castor bean shoot dry mass production was found in CXve and TCo soils. It ranged from 34.65 to 33.55 g vessel in the treatment containing the lowest P dose applications (87.94 mg dm and 104.33 mg dm, respectively). Received 16 March 2016; Revised 13 Jan 2017; Accepted 7 March 2017.

Chemical Characterization of Organic Residues in Agroindustrial and Urban Waste using Energy Dispersive X-ray Fluorescence Spectrometry

Treated and reused industrial residues and urban waste are depicted as potential alternative sources for agricultural use. In this context, the objective of this study was to determine the chemical element concentrations in organic residues from the Medium-High Uruguay Region of the Rio Grande do Sul, using energy dispersive x-ray fluorescence spectrometry (EDXRF). The organic compounds analyzed were meat agroindustry sludge, organic composites from agribusiness meat, and organic compounds from urban waste (particle sizes: >4.75 mm, <4.75 mm to >2.00 mm, and <2.00 mm). The results showed that chemical elements found in greater concentrations were calcium, silicon, iron, aluminum, phosphorus, sulphur, and potassium. Thus, the EDXRF technique proves to be efficient for characterizing organic compounds and that these residues are appropriate as alternative sources of organic fertilizer that can be applied in an efficient and safe manner in agricultural systems.