Volume 22, Number 2, 1998

Soils from the Vale do Rio Doce region in Ipatinga, Nova Era e Guanhães counties, State of Minas Gerais, Brazil, under reforestation with Eucalyptus grandis, were studied. Eight forest sites with soils from different taxonomic classes were selected and detailed mineralogical characterization and evaluation for nutrient reserve potential were conducted in 1991. The soils studied were mineralogically classified as: Kaolinitic-non sesquioxidic (2 and 5); kaolinitic-sesquioxidic (1); gibbsitic-sesquioxidic (4, 6 and 7); hematitic (3) and gibbsitic (8). The main silicate clay […]

This experiment was carried out in the Department of Soil Science of the Federal University of Viçosa, Minas Gerais State, Brazil, with the objective of evaluating the effect of P concentration and the duration of the P-omission period on three different fractions of P in Eucalyptus seedlings: i) total soluble P (TSP); ii) inorganic P (IP); and iii) organic P (OP). A solution containing high amount of phosphorus (8 mg L-1 of P) was added to five species of Eucalyptus […]

Despite the fact that aluminum toxicity to crops is eliminated near soil water pH of 5.5, lime recommendation in many regions aims to increase soil pH up to 6.0 or even higher. For highly buffered soils, high rates of limestone are required to raise the pH from 5.5 to 6.0, resulting in additional, sometimes unnecessary, costs. The objective of this study was to evaluate the effect of soil pH on corn yield in a very acid Hapludox. The experiment was […]

This research was conducted from May to September, 1995, in order to evaluate liming criteria for rice plants on flooded soils of Minas Gerais State, Brazil. The effects of increasing CaCO3 + MgCO3 dosis on dry matter production were evaluated in a greenhouse pot trial. The experimental matrix was a complete factorial with ten lowland soils and five levels of liming. The soil characteristics which significantly affected the lime levels recommended were: titrable acidity at pH 7,0 (H + Al), […]

The effects of continuous sugarcane cropping on the chemical properties of a clayey Yellow Latosol were studied in the region of the Low Coastal Tablelands of Alagoas State, Brazil. Four sites were selected at Caeté mill, São Miguel dos Campos, State of Alagoas, Brazil, involving a native forest (Tn) and sugarcane fields, cultivated for periods of two (T2), eighteen (T18) and twenty-five (T25) years. The soils were morphologically characterized and samples were taken from each horizon to determine pH (H2O […]

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 […]

This research was carried out in Rio Grande do Sul State, Southern Brazil, during the 1990/1991 summer harvest. The main objective was to evaluate the aggregation and aggregate stability of two clayey soils classified as Dusky Latosol (Haplorthox) and Dark-Red Podzolic (Paleoudult). Two treatments were used in the Haplorthox: grass (Setaria anceps L.); and crop rotation under conventional tillage (wheat (Triticum aestivum) soybean (Glycine max L.)). On the other hand, four treatments were used in the Paleoudult: grass (Digitaria decumbens […]

Utilization of soil erosion models requires data on soil canopy cover and crop height. Equations to describe the relationship of aboveground biomass to soil canopy cover and height of the corn, cotton, dry bean, potato and soybean crops were developed from data collected at farm plots in several municipalities of the State of Paraná during the 94/95 crop year. Canopy cover and height, and aboveground biomass were collected at fifteen-day intervals. Yield was determined by manual harvest. The relations utilized, […]

In general, farming systems have contributed to highly unstable conditions in agroecosystems, resulting in severe environmental degradation. The present study aims to verify the potential of green manure use in the São Carlos region (SP), as a complementary technique to cropping systems present in the region under investigation, with the objective of improving the quality of its agroecosystems. The region was delimited based on its climate, geomorphology and administrative characteristics, obtained from basic maps and handled through a Geographic Information […]

Increase in soil pH by liming has been considered sufficient to assure Mo availability for crops. In soybean, the high response to liming might be related to additional demand of Mo for nitrogenase complex activity, in relation to other non-nitrogen fixing crops. Therefore, this research planned to study lime-Mo interactions for soybeans and sorghum crops, in a Red-Yellow Podzolic soil from the Mococa Experimental Station, Instituto Agronômico, State of São Paulo, Brazil, during the period 1985 to 1989. The treatments […]