ABSTRACT Root growth can be limited by physical and chemical conditions of the soil. Compacted and acidic soils, where there is an occurrence of exchangeable Al, constitute barriers to use of the soil by plant roots. The hypothesis of this study was that physical and chemical properties of the inter-row soil of a peach orchard influence the root distribution of different rootstocks. The aim of this study was to describe and register the soil physical and chemical properties and root distribution in the soil profile of the inter-row of seven years old mature peach (Prunus persica) orchard. Samples of soil (classified as an Argissolo Vermelho Distrófico típico [Rhodic Paleudult] with 180 g kg-1 clay, 120 g kg-1 silt, and 700 g kg-1 sand) and roots were collected from orchard inter-rows of ‘Maciel’ peach, grafted onto ‘Okinawa’ and ‘Nemaguard’ rootstock, at 1.5, 2.0, and 2.5 m from the trunk, and at every 0.10 m, up to a depth of 0.50 m. The soil samples were sieved and the roots washed. A subsample was removed from each sample for chemical analysis. Resistance to penetration (RP) was used as an indicator of soil compaction. A close relationship was found among chemical properties, RP, and root distribution. Root density was affected by the presence of compacted regions (RP >2,000 kPa) and by high Al saturation in the exchange complex in the soil profile. There was a reduction in the frequency of thick roots (Ø >2 mm) in the samples collected in portions of compacted soil and at increasing soil depth. The compacted portion of the inter-row limits lateral distribution of the peach tree root system, while aluminum limits its depth.

Demand for organic products is intensified in many countries each year. Following this trend, Brazil produces increasing volumes of organic grape juice. In this way, a survey of organic grape juices made from grapes produced according to this system was carried out where physicochemical composition, minerals, trace elements, and pesticide residues were determined. Variables related to grape juice composition were performed by physicochemical procedures; minerals and trace elements, by inductively plasma optical emission spectrometry; pesticide residues, by liquid chromatography-mass spectrometry. Main results show that the physicochemical composition of organic grape juices was in general in accordance to the Brazilian legislation. The mean concentrations of trace elements were very low, varying from 0.002 (Cd) to 0.970 (Ba) mg L–1. Pesticide residues were not detected in any sample analyzed (MRL= 10 µg L–1). These results show that the Serra Gaúcha viticultural region present conditions to produce organic grape juices, despite the adverse climate factors that occurs in some years. Nevertheless, these products should be made with grape varieties, such as the labrusca ones, less susceptibles to the main grapevine pathogens.