Enhanced degradation of the fungicide metalaxyl was investigated in two soils: a gley humic (GH) and a Dark Red Latosol (LE), collected at sites never exposed to the fungicide. The soil samples were treated with successive applications of metalaxyl as a commercial formulation and 14C-metalaxyl in laboratory. Metalaxyl biodegradation was analyzed during 63 days by means of radiometric techniques to verify biomineralization and degradation product formation from the applied 14C-metalaxyl. Although biomineralization (maximum of 14 and 8% in the GH […]

Erosion is one of the main causes of soil degradation because of the transport of nutrients. The nutrients are transported by water either dissolved or adsorbed on the soil particles, and the erosion rate may vary according to the tillage system. This work was conducted at the Centro de Ciências Agroveterinárias in Lages, Santa Catarina, Brazil, from January 1993 to October 1998, to quantify the losses of phosphorus, potassium, calcium, magnesium and organic carbon due to erosion caused by natural […]

Soil compaction of the agricultural soils is a result of soil machine interactions, which influence physical and biological soil properties and their relations with crop growth and yield. The objective of this study was to determine the compression index, the preconsolidation pressure and the soil strain of a Haplortox (LE) and a Paleudalf (PV), with different initial state of compaction and water saturation. Undisturbed soil samples were collected in two soils and at two depths, at no tillage and conventional […]

The purpose of this work was to verify the effect of hidroretentive polymers on the physical and hydraulic properties of two porous media. The experiments were carried out at the Soil Physics Laboratory at the Federal University of Paraná from 03/18 to 10/30/97. The research was developed using a Belgium type of retentive polymer incorporated in two porous media with their different physico-chemical properties; a Dark Red Oxisol and Marine Quartzous sand. The polymers were applied as dried grains at […]

Raindrop impact and runoff are the active agents of water erosion, which is influenced by soil roughness and cover, crop type and tillage system. Conservation tillage reduces water erosion in relation to conventional tillage by means of surface roughness and cover. This work was conducted in Centro de Ciência Agroveterinárias, in Lages, Santa Catarina, Brazil, from January 1993, to October 1998 to quantify soil and runoff losses under natural rainfall in the following soil tillage downslope systems: no-tillage, chisel plow […]

The aim of this study was to select and partially characterize efficient nitrogen-fixing rhizobia associated to pigeonpea from coastal tableland areas in the Northeast of Brazil. Sixteen rhizobia from different coastal tableland areas were evaluated under greenhouse condition, at the Embrapa Coastal Tablelands (Aracaju, Sergipe, Brazil). Four isolates performed better than the others in relation to shoot N content (NC), shoot dry weight (SDW), leaf area (LA) and nodule dry weight (NDW). NDW showed high correlation with SDW, LA and […]

The effect of nitrogen levels on the growth and yield of garlic plants grown from tissue culture and conventional propagation. The trial was conducted at an experimental field of the Plant Science Department/UFLA, Lavras, MG, Brazil. A complete randomized block design in a factorial scheme with four replications was used. Plants originated from two propagation methods-tissue culture and conventional and five levels of nitrogen fertilizer – 0, 35, 70, 105 and 140 kg ha-1 were applied during the treatments. Plant […]

The efficiency of surface application of lime under a no-tillage system is doubtful, particularly with regard to subsoil acidity and to methods of lime requirement determination. A field experiment was carried out on a dystrophic Dark Red Latosol (Haplortox) from Ponta Grossa, Paraná, Brazil, from 1993 to 1998, to evaluate the extent of downward movement of lime applied on the surface under a no-tillage system, and the effect on crop rotation grain yields. A randomized complete block design was used, […]

Redox processes affect the reactivity of iron oxides and this can affect the P availability in soils. To evaluate how this processes can affect phosphorus availability, this study was carried out with six Uruguayan soils, which differed in their parent material, and subjected to alternation of the flooded-drained conditions. Soil samples (0-15 cm) of the A horizon, were flooded during 0, 5, 15 and 45 days, drained and sampled after 21 days of air-drying. Fe extracted by ammonium oxalate at […]

The aim of this study was to evaluate the effects of vinasse (100 and 200 m3 ha-1) on the degradation and sorption of diuron in Rhodudalf and Haplorthox soiIs. For the degradation study an experiment was carried out in a completely randomized design with a factorial experiment of 2 (soils) x 3 (vinasse: 0, 100 and 200 m3 ha-1), for 120 days. The mineralization was evaluated by radiorespirometry. At the end of the incubation, the original compounds and their metabolites […]