Nutrition, dry matter accumulation and partitioning and phosphorus use efficiency of potato grown at different phosphorus levels in nutrient solution
01/Nov/2012
High rates of phosphate fertilizers are applied to potato (Solanum tuberosum L.), which may cause antagonistic interactions with other nutrients and limit crop yields when over-supplied. The purpose of this study was to evaluate the influence of phosphorus (P) levels in nutrient solution on P use efficiency, nutritional status and dry matter (DM) accumulation and partitioning of potato plants cv. Ágata. The experiment was carried out in a greenhouse, arranged in a completely randomized block design with four replications. Treatments […]
Sulfur in agriculture
01/Nov/2012
Sulfur (S) deficiency in soils is becoming increasingly common in many areas of the world as a result of agronomic practices, high biomass exportation and reduced S emissions to the atmosphere. In this review, the incidence and commercial exploitation of S pools in nature are discussed, as well as the importance of S for plants and the organic and inorganic S forms in soil and their transformations, especially the process of microbiological oxidation of elemental sulfur (S0) as an alternative […]
Nodulation and nitrogen fixation efficiency of cowpea as affected by inoculum rate
01/Nov/2012
Cowpea (Vigna unguiculata (L.) Walp.) can obtain sufficient N for its own supply from the atmosphere, by the process of biological nitrogen fixation (FBN), when associated with specific and effective rhizobia bacteria. The purpose of this study was to evaluate the effect of different rhizobia inoculum rates on nodulation and biological N fixation by cowpea (cv. BRS Pujante). A complete randomized block design with seven treatments and four replicates was used. The trial was conducted in a greenhouse using 2 […]
Estimating subsoil resistance to nitrate leaching from easily measurable pedological properties
01/Nov/2012
Leaching of nitrate (NO3–) can increase the groundwater concentration of this anion and reduce the agronomical effectiveness of nitrogen fertilizers. The main soil property inversely related to NO3– leaching is the anion exchange capacity (AEC), whose determination is however too time-consuming for being carried out in soil testing laboratories. For this reason, this study evaluated if more easily measurable soil properties could be used to estimate the resistance of subsoils to NO3– leaching. Samples from the subsurface layer (20-40 cm) […]
Carbon and nitrogen stocks in soil under castor bean in the semi-arid Caatinga of Brazil
01/Nov/2012
Much of the Brazilian castor bean (Ricinus communis L.) production is concentrated in the semi-arid region (Caatinga biome) of the Northeast, as an alternative crop. The purpose of this study was to evaluate changes in C and N pools due to land use change in the Caatinga biome by castor bean production. The study was conducted on the Fazenda Floresta in the municipality of Irecê (Mid -North region of Bahia, Brazil). The climate is type BSwh (Koppen) – Semi-arid climate. […]
Micromorphology of spodic horizons of the restinga region of São Paulo State
01/Nov/2012
The soils, especially the Spodosols, of the “restinga”, a coastal plain, are poorly studied and understood in Brazil. In this work, the micromorphology of spodic horizons was investigated at four sites of the coastal plain of the State of São Paulo (Bertioga, Ilha de Cananeia, Ilha do Cardoso, and Ilha Comprida). This allowed the characterization of different organic matter forms. These data, together with macromorphology, were used in the analysis of the main processes involved in the genesis of spodic […]
Soil quality index associated to the groundwater recharge (SQIGR) in the Upper Rio Grande Basin, Minas Gerais
01/Nov/2012
In the last years, soil quality indexes for analyses of the environmental sustainability and agricultural production have been proposed in increasing numbers. However, none of these indexes is related to the groundwater recharge soil quality index for conditions in Brazil. The objective of this study was to generate a soil quality index related to the groundwater recharge (SQIGR) of the physiographical conditions of the Upper Rio Grande Basin and to draw a map of SQIGR using geostatistical procedures. The proposed […]
Soil physical properties and rice straw levels in management systems: effect on irrigated rice yield
01/Nov/2012
The State of Rio Grande do Sul is the greatest producer of flooded rice of Brazil, concentrated mostly along the western border. The objective was to evaluate soil physical properties and flooded rice yield in no-till and conventional tillage systems and rice straw levels in no-till system. The study consisted of four experiments (E), laid out in experimental design was completely randomized blocks, with four experiments (E) and 10 repetitions in experiment 1, 2 and 3 and 6 in experiment […]
Integration of ruler to measure depth in the design of a Stolf impact penetrometer
01/Nov/2012
The Stolf impact penetrometer is a dynamic cone penetrometer to measure soil resistance, in use since its release in 1982. In the original design, a centimeter scale to measure penetration depth was engraved on the proper penetration rod. The idea was to make the equipment easier to understand for farmers and to allow direct readings on the penetration rod while also avoiding additional parts. The purpose of this study was to incorporate a millimeter ruler to enable the operator to […]
Physical quality of Oxisols under no-tillage in the Savanna region of Piaui
01/Nov/2012
The Cerrado is being increasingly exploited in production systems characterized by intensive land use, without due concern for the preservation of natural resources. The objective of this research was to evaluate the effect of no-tillage soybean on the physical properties of Oxisols. The study was carried out in the region of “Serra do Quilombo”, located in the Cerrado region of the State of Piauí. To assess changes in soil properties caused by agricultural use, soil samples were collected from conventional […]