Degradation and sorption of ametryne in two soils with vinasse application

Este trabalho teve o objetivo de avaliar os efeitos da adição de vinhaça nos processos de degradação e sorção do herbicida ametrina em solos das classes Terra Roxa Estruturada (TR) e Latossolo Vermelho-Amarelo (LV). No estudo da degradação foi instalado um experimento, em delineamento inteiramente casualizado arranjado em fatorial 2 (solos) x 3 (doses de vinhaça: 0, 100 e 200 m3 ha-1), que foi conduzido por 120 dias. A mineralização foi avaliada por radiorrespirometria. Após os 120 dias, o herbicida foi extraído do solo e detectado em "radio-scanner". Paralelamente, foi conduzido um ensaio para avaliação do efeito das doses de vinhaça juntamente com a ametrina na atividade microbiana, pH e C orgânico do solo. O experimento de sorção foi realizado com os mesmos tratamentos empregados no estudo de degradação, utilizando-se cinco concentrações do herbicida. A degradação da ametrina foi maior na presença de 100 m3 ha-1 de vinhaça. A adição do resíduo contribuiu para o aumento da atividade microbiana e do pH. A ametrina foi pouco sorvida nos dois solos, não apresentando influência da adição da vinhaça.The aim of this study was to evaluate the effects of vinasse (100 and 200 m3 ha-1) on the degradation and sorption of ametryne in Rhodudalf and Haplorthox soils. For the degradation study an experiment was carried out in a completely randomized design with a factorial experiment of 2 (soils) x 3 (vinasse doses: 0, 100 and 200 m3 ha-1), that was carried by 120 days. The mineralization was evaluated by radiorespirometry. At the end of the incubation (after 120 days), the herbicide was extracted from the soils and detected in the radio-scanner. In parallel, another experiment was carried out in order to evaluate the effect of the vinasse doses and herbicide on the microbial activity, pH and organic carbon content of the soil. The sorption experiment was carried out under the same conditions as the degradation study, with five herbicide concentrations. The ametryne degradation was higher in the presence of 100 m3 ha-1 of vinasse. The vinasse addition increased the microbial activity and the pH. The sorption of ametryne was low and not affected by vinasse

Atributos de solos tropicais e a sorção de imazaquin

Imazaquin is an acid herbicide widely used in Brazil to control weeds associated to the soybean crop. The purpose of this research was to study imazaquin sorption and its relation to CEC, pH and organic carbon (OC) and clay contents of eleven tropical soil samples. In order to establish the sorption isotherms, imazaquin solutions at concentrations of 0.53, 0.88, 1.45, 2.71, and 5.20 mg mL-1 were prepared in 0.005 mol L-1 CaCl2 solution with the addition of radiolabeled tracer (14C-imazaquin). The sorption coefficients (Kf) were calculated according to the linear shape of the Freundlich isotherm equation. Imazaquin sorption ranged from low to moderate (Kf < 3.0), except for the Aquox soil. OC content and pH were the soil attributes that best correlated to imazaquin sorption. The incorporation of clay content in the regression analysis increased the model×s precision by 20 %. Imazaquin shows higher availability and, therefore, higher leaching potential when applied to soils with pH higher than 6 and low contents of OC and clay.O imazaquin é um herbicida com caráter ácido, de uso intensivo no Brasil para controlar plantas daninhas associadas à cultura da soja. Estudou-se a sorção do imazaquin e a sua relação com a CTC, o pH e os teores de carbono orgânico (Corg) e argila de onze amostras de solos tropicais. Para a obtenção das isotermas de sorção, soluções de imazaquin nas concentrações de 0,53; 0,88; 1,45; 2,71 e 5,20 mg mL-1 foram preparadas em CaCl2 0,005 mol L-1 com a adição de um traçador radioativo (14C-imazaquin). O coeficiente de sorção (Kf) foi calculado a partir da equação linearizada de Freundlich. A sorção do imazaquin variou de baixa a moderada (K

Water Quality Assessment in Piracicamirim Creek Upstream and Downstream a Sugar and Ethanol Industry Through Toxicity Tests With Cladocerans

An environmental impact study was conducted to determine the Piracicamirim's creek water quality in order to assess the influence of effluents from a sugar industry in this water body. For this, toxicity tests were performed with a water sample upstream and downstream the industry using the microcrustaceans Daphnia magna, Ceriodaphnia dubia and Ceriodaphnia silvestrii as test organisms, as well as physical and chemical analysis of water. Results showed that physical and chemical parameters did not change during the sampling period, except for the dissolved oxygen. No toxicity was observed for D. magna and reproduction of C. dubia and C. silvestrii in both sampling points. Thus, the industry was not negatively impacting the quality of this water body.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP