To evaluate residual effects of potassium fertilization throught ryegrass on subsequent rice, under no-tillage system, a field experiment was performed from May 1996 to April 1997 in the Agricultural Center (Centro Agropecuário) of Palma/UFPel, in the county of Capão do Leão, Rio Grande do Sul State, Brazil. The examined soil was a Planossolo (Albaqualf) belonging to the Pelotas mapping unit. Treatments consisted of three K levels applied on the ryegrass (0, 0.5 and 1 time the recommended dose of 70 […]

This study was carried out to evaluate the effect of cultivation systems on soil carbon and nitrogen contents and on the distribution of light and heavy fractions of soil organic matter (SOM). Density and particle-size fractionations were used to isolate free light fraction (FLF), intra-aggregate light fraction (ILF) and heavy fractions (HF) of a Red-Yellow Latosol from a field experiment at Embrapa Rice and Beans in Goiás, Brazil. Treatments consisted of a combination of soil tillage and crop rotation. Soil […]

Soil fertility characteristics were evaluated on a typical dystrophic Red Latosol located in Passo Fundo, Rio Grande do Sul, Brazil, after five years of combined production systems (1993 to 1997). The effects of integrated grain production systems and with winter annual and perennial pastures under no-tillage were assessed. Four production systems were evaluated: system I (wheat/soybean, white oat/soybean, and common vetch/corn); system II (wheat/soybean, white oat/soybean, and grazed black oat + grazed common vetch/corn); system III [perennial cool season pastures […]

This study was carried out to assess the influence of Winter plant cover on the physical soil properties in a Structured Terra Roxa soil in the state of Santa Catarina. The plant cover consisted of an association of black oats (Avena stirgosa Schreb) with pasture turnip (Raphanus sativus L.) and organic fertilization with poultry manure and 2 mineral fertilization. Soil samples collected in August 1994 and January 1995, at depths of 0-10, 10-20 and 20-30 cm, from an experiment started […]

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 […]

The no-tillage system with grain crops occupies today 2.5 millions hectares in the state of Paraná. Besides the traditional rotation system with wheat and soybean, in many areas green manure cover crops are also sown in the Winter and corn in the Summer. The objective of this study was to evaluate changes in some of the soil chemical properties after eight years under the crop rotation systems: wheat-soybean-black oat-soybean (WOS), wheat-soybean-lupine-corn-black oat-soybean (LCO), lupine-corn-wheat-soybean (LC) and compare them with the […]

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 objective of this paper was to study the effect of eight soil tillage systems on the aggregation status of an Albaqualf at a depth of 0-10 cm using the following parameters: distribution of water stable aggregates in different size classes and mean weight diameter aggregates. The field experiment was carried out at the “Empresa Brasileira de Pesquisa Agropecuária – Centro de Pesquisa Agropecuária de Clima Temperado” (EMBRAPA-CPACT) experimental station, in Pelotas (RS) in 1985. After ten years, the soil […]

In the no-tillage system, the absence of soil revolving, combined with the traffic of machines, promotes excessive soil surface compaction. An experiment was conducted in the county of Ponta Grossa, State of Paraná, Brazil, during the agricultural years of 1989/1990 and 1990/1991, with the objective of studying several factors that intervene in this process. This research compared the effects of three previous soil tillage methods and two liming levels on several physical properties of a clayey Dark Red Latosol under […]