Potassium leaching as affected by soil texture and potassium availability
01/Dec/2008
A correct potassium fertilization management, using adequate fertilizer amounts, can minimize K losses and avoid soil K depletion. The objective of this study was to evaluate potassium dynamics in the soil profile as affected by different textures and exchangeable K levels resulting from previous soybean fertilizations. Soils with sandy loam and clayey texture previously planted with soybean and fertilized with 0, 60, 120 and 180 kg ha-1 K2O were sampled during 6 years. The experiment was carried out in a […]
Applicability of the lisem (limburg soil erosion model) model for hydrological simulation in a tropical watershed
01/Dec/2008
The most important parameters of the LISEM model associated to surface runoff production (antecedent soil moisture (θap) and soil layer thickness), were calibrated by individual precipitation events in the Marcela Creek Watershed, Alto Rio Grande Region, MG. The hydrological effects of different land-uses in the watershed were also simulated. The model was highly sensitivity to soil moisture, which was the most important calibration paramete. The influence of the water balance layer was related to the soil moisture during calibration. It […]
Water-soluble organic compounds in plant residue and the effects on soil chemical properties
01/Dec/2008
The water-soluble organic compounds of plant residues released on the soil surface can improve the subsoil fertility, due to the neutralization of acidity and Ca and Mg transport. An experiment was conducted at the Instituto Agronomico do Parana (IAPAR), Londrina, to evaluate the effect of water-soluble organic compounds of plant extracts on the chemical characteristics of a dark Red Latosol (Typic Haplortox), on soil samples in columns. The treatments consisted of: distilled water, lime incorporated in the 0-5 cm soil […]
Soil reclamation by green manure and soil ammendements in areas degraded by hydroelectric power plant construction
01/Dec/2008
Loan areas near hydroelectric power plants can be considered degraded areas since they were stripped of their soil surface horizons. This study aimed to investigate the recovery of soil chemical attributes of a Red Latosol (Oxisol) used in the embankment and fill of the hydroelectric system in Ilha Solteira, São Paulo, Brazil, by green manure, lime and gypsum. The experiment had a randomized block design with seven treatments and four replications. The treatments consisted of: one control (tilled soil and […]
Limestone application methods and cover crops in the implementation of the no-till system on a cerrado soil
01/Dec/2008
The objective of this study was to evaluate soil correction in the implantation of the no-till system in an Oxisol of the Cerrado, Selvíria – MS, Brazil (20º 22´ S, 51º 22´ W). The treatments consisted of five lime application forms, in only one or split rates and two cover crops. Liming without incorporation, independent of the application form, corrected soil acidity and increased Ca and Mg levels in the 0-0.05 m layer; in the other layers these attributes were […]
Physical properties and organic matter content of an ultisol cultivated with cassava under different managements
01/Dec/2008
The maintenance and improvement of soil quality are crucial to the stability, sustainability and productivity of natural ecosystems and agroecosystems. The understanding and quantification of the impact of tillage systems in their physical quality are fundamental in the development of sustainable agricultural systems. This study was carried out to evaluate the effects of management practices on physical properties and organic matter content of an Ultisol cultivated with cassava following the use of distinct cover crops. A field experiment was carried […]
Multivariate analysis of soil microbiological and chemical attributes in forests with Araucaria angustifolia
01/Dec/2008
Araucaria angustifolia is an endangered tree species in Brazil and little is known about the soil attributes of these pine forests. This study was carried out to identify differences between natural and reforested Araucaria areas, in terms of soil microbiological and chemical attributes, with multivariate canonical discriminant analysis (CDA) and canonical correlation analysis (CCA). The studied areas included: 1. native forest with Araucaria (NF); 2. Araucaria reforestation (R); 3. Araucaria reforestation burnt by an accidental fire (RF); and 4. native […]
Use of urea in mix with ammonium sulfate or gypsum in the culture of corn
01/Dec/2008
Qualitative and quantitative aspects must be considered in the side-dressing fertilization in the cultivation of corn. This study aimed to evaluate in the counties of Votuporanga (SP) and Uberlândia (MG), the effect on productivity of corn using different mixtures of granules in the side-dressing fertilization, containing nitrogen (N) and sulphur (S). In Votuporanga (SP), in an Argisol (120 g kg-1 of clay) were estimated losses through volatilization of NH3-N granules mix consisting of urea (U) + ammonium sulfate (AS) or […]
Chemical attributes of an oxisol under no-tillage submitted to surface liming and distinct grazing pressures in a crop-livestock integration system
01/Dec/2008
The use of large areas occupied only with winter soil cover crops for cattle grazing may become an alternative income source for summer grain producers in southern Brazil. The presence of cattle in areas used only with no tillage crops may, however, affect soil attributes, depending on the management type. This study aimed to evaluate the effects of surface liming on the chemical attributes of a Red Latosol (Oxisol) under no-tillage and crop-livestock integration. Treatments consisted of pasture management at […]
Soil organic carbon budget under crop-livestock integration in southern Brazil
01/Dec/2008
In southern Brazil, crop-livestock integration is increasing in areas traditionally used for extensive beef cattle production. The poor winter pasture management associated to the use of soybean monoculture in the summer may be restrictive for the incorporation of plant residues into the soil and reduce soil organic carbon stocks. The objective of this study was to evaluate the impact of the increase of winter pasture grazing frequencies and summer crop systems on the soil organic C stock. The experiment was […]