Successive applications of cupric fungicides to grapevine can increase total copper concentration in the soil and modify its desorption in the soil profile. This study was carried out in 2006 in the soil chemistry and fertility laboratory of the Universidade Federal de Santa Maria to evaluate copper forms and desorption dynamics in Udorthent and Haplumbrept soils (in the layers 0-20 and 20-40 cm) under grapevine for 40 years and under successive applications of cupric fungicides. The soils were collected in […]

The aim of this study was to evaluate the sorption and desorption of imazaquin in soils with different granulometric, chemical and mineralogical characteristics. Isotherms and kinetics studies were carried out to quantify the hysteresis between sorption and desorption processes. The soils were classified as Rhodic Hapludox (LVdf), Typic Hapludox (LVA) and Typic Quartzipsamment (RQ). The soils were air-dried and passed through a 2 mm mesh sieve, and the chemical, physical and mineralogical properties characterized. The radiolabeled molecule (14C) was imazaquin, an […]

Pesticide kinetics and sorption allow to predict the equilibrium time of the reaction and to speculate over the reaction mechanisms involved.Therefore, their study is fundamental to understand the environmental fate of pesticides.The aim of this research was to evaluate the sorption and kinetics of the fungicide chlorothalonil in five distinct soils with different organic matter contents of the state of São Paulo (Brazil): Neossolo Quartzarênico órtico (RQo), Latossolo Vermelho distroférrico (LVdf-1 e LVdf-2), Latossolo Vermelho perférrico (LVj), and Gleissolo (G).The […]

Kinetics studies of potassium release from soils can improve our knowledge about its availability to plants. The present study, carried out in 1993, was undertaken to investigate the kinetics of potassium release and to compare four kinetics equations to describe the K-release from three soils of the State of Rio Grande do Sul, Brazil. Samples of A horizons of a Vertisol, of an Ultisol and of an Oxisol, were equilibrated with a cation exchange resin (IR-120) from one minute up […]