No abstract

(1):111-120. Potted gerbera is an ornamental plant that is widely commercialized in Brazilian markets. However, information on cultivation techniques is needed to meet growing demand, especially with regard to fertilization. This study was carried out to assess the growth of potted gerbera, Florist Red Black cultivar, with mineral and organic fertilization. The experiment was conducted in a greenhouse located at UNIOESTE -Cascavel Campus -PR. The experimental design was composed of randomized blocks with four replicates and five treatments. Treatments were defined according to the fertilization source, which were mineral (NPK) and organic. Organic fertilizers were obtained by diluting in water four organic composts from agroindustrial-waste composting processes. After obtaining composts, water dilution was performed, adjusting the nutritive solution electrical conductivity values. Gerbera plants were assessed fortnightly (0, 14, 28, 42, and 56 days after acclimatization) for leaf area and shoot dry matter, which were adjusted for time using the ANACRES program to obtain the leaf area ratio (LAR), relative growth rate (RGR), and net assimilation rate (NAR). Fifty-six days after acclimatization, plants were assessed for number of leaves, plant diameter, leaf area, leaves and inflorescences dry phytomass, stem height, head diameter, and stem diameter. The highest relative growth rates were obtained in plants grown with organic compost in treatment 3. However, the net assimilation rate, which indicates dry matter conversion efficiency, was highest in plants with chemical fertilization (treatment 1).

Swine wastewater (SW) application in agricultural soils may affect its microbial community in a long term. The objective of this study was to evaluate prospective changes in soil bacterial community after eight years continuous application of swine wastewater. The wastewater doses tested were 0; 100; 200 and 300 m 3 ha -1 , being applied from the beginning of the experiment and with or without recommended fertilization. Three soil samples were taken from each plot for determinations of basal respiration, microbial biomass and metabolic quotient. We also performed DGGE analysis and made a correlation between soil chemical conditions and microbial activity. Microbial community underwent significant structural changes from swine wastewater applications. Higher SW doses (200 and 300 m 3 ha -1 ) influenced significantly (p <0.05) and benefitted certain bacteria groups.

ABSTRACT:The knowledge of pesticide residual concentrations in the environment is important to understand the threats to the environment and human health, especially when natural resources are used for human consumption. In this context, this study aimed to assess the potential ecological risk and respective sources of sediment contamination by organochlorine and organophosphorus pesticides. The study site was an urban lake located in Cascavel city, western Paraná state, Brazil, where the history of land use and occupation in the urban environment is typically agricultural. Surface sediment samples were collected every three months from April 2010 to June 2013 at five different collection points, totaling 65 samples. Analyses showed that contamination by organochlorine pesticides is related to agricultural activities in the past, with a low ecological risk to benthic organisms. Conversely, organophosphorus pesticides presented a recent and continuous contamination from urban activities, with a risk coefficient, especially for disulfoton, indicating a significant potential adverse effect on organisms. However, in general, the obtained results did not indicate an immediate risk to public health.

The aim of this study was to investigate the temporal evolution of the supply of chemical elements to the Upper Paraná River floodplain and identify trends in the geochemistry of its drainage basin. The primary factor that regulates the supply of chemical elements of the Upper Paraná River floodplain is the flood pulse, which can be magnified by the El Niño-Southern Oscillation. Garças Pond is affected by agriculture, urbanization, discharge of industrial effluents and hydroelectric power production activities. Patos Pond is affected by sugarcane burning, gold mining, agriculture and urbanization.