Doses and methods of manganese fertilization and its effect upon the production of upland rice
01/Sep/2001
This work was conducted under greenhouse conditions to evaluate how doses and methods of manganese (Mn) application may affect vegetative characteristics as well as the production of upland rice. The treatments consisted of five manganese doses applied either via soil (0, 4, 8, and 16 mg dm-3) or leaf (3 4 g L-1 applications), associated with two rice cultivars (Canastra and Confiança). The experiment was randomly designed, with four replications, in a 2 x 5 factorial scheme. Each plot consisted […]
Characterization of tableland atlantic forest ecosystems according to humus forms
01/Sep/2001
Humus forms allow the characterization of either a natural forest ecosystem or disturbed forests. Under this perspective, we aimed to identify the humus forms in three Tabuleiro Forest sites in northern Espírito Santo: two primary forests, “Mata Alta” and “Mata de Córrego”, and one secondary forest resulting from slash and burn, over 40 years old (Capoeira Queimada). Therefore, the holorganic horizons were studied in regard to the pedological parameters of the mineral soil. At “Mata Alta”, a mesotrophic mull was […]
Effect of grain and forage crop production systems under no-tillage on soil fertility after five years
01/Sep/2001
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 […]
Influence of subsurface soil compaction on the growth of the aerial parts and roots of winter green manure species
01/Sep/2001
Soil compaction has been a very common problem on the fields, affecting growth and yield of the crops as well as soil and water conservation. In order to study this problem, five winter green manure species (Vicia sativa; Raphanus sativus; Lupinus albus; Avena strigosa and Avena sativa) were cultivated in four soil profiles with increasing levels of subsurface compaction (soil bulk densities: 1.31, 1.43, 1.58 and 1.70 Mg m-3). The experiment was carried out in pots under greenhouse conditions at […]
Nitrogen mineralization in natural and forest plantation ecosystems of São Paulo state
01/Sep/2001
This study analyzes homogenous stands of Eucalyptus grandis and Pinus caribaea var. hondurensis in different growth stages as well as fragments of natural vegetation of “Cerrado” and Atlantic Forest. The climatic, edaphic and floristic conditions of the chosen areas are representative of the native forests and forest plantations established at the Western plateau of the state of São Paulo. Soil samples (0-15 cm) were incubated under aerobic and anaerobic laboratory conditions by successive periods of 3, 3, 4, 4, 6 […]
Calcium-phosphate solubilizing bacteria occurrence on the roots of brazilian Amazonia plants
01/Sep/2001
The use of phosphate-solubilizing bacteria can be a low-cost alternative to agroforestry systems in the Amazônia, where prices, transport, and producers’ low buying capacity make the use of soluble fertilizers difficult. On soils without a cultivation past, phosphates are combined mainly to Al, while on previously limed and cultivated soils, these phosphates are combined with Ca, limiting their use by plants. There is little information on phosphate-solubilizing bacteria (BSF) in the Amazon; thus, further studies are needed. The first step […]
Porosity characteristics of a Red-Yellow Podzolic under different tillage systems
01/Sep/2001
The porosity characteristics of a Red-Yellow Podzolic was evaluated after 10 years of cultivation, under the following soil management treatments: no-tillage, moldboard plowing + disking, disk plowing + disking, off-set disk harrowing followed by moldboard plowing + disking, off-set disk harrowing followed by disk plowing + disking and off-set disk harrowing followed by disking. Undisturbed 15 cm high and 15 cm deep soil blocks, were sampled for morphometric analysis of the soil porosity. Results indicated the presence of surface sealing […]
Restriction to root growth in the B textural horizon
01/Sep/2001
Plant water and nutrient uptake depends on several factors, mainly on the soil depth explored by the roots. Some soil factors and processes can limit root growth. The objectives of this study were: (a) to quantify the relationships among corn root density with several soil properties and to identify which of these attributes restrict root growth in the Bt horizon and corn yield; (b) to measure the temporal variation of the soil water content to verify if plants extract water […]
Comparison of extraction methods for copper, zinc, iron and manganese in soils of the state of Rio de Janeiro, Brazil
01/Sep/2001
The consequences of micronutrient deficiency or toxicity for the agricultural productivity in the state of Rio de Janeiro are not adequately known. For this reason, in 1997, the levels of copper, zinc, iron, and manganese were quantified in 103 samples from surface horizons of representative soils of the state. The extractant solutions used were Mehlich-1, DTPA-TEA, and HCl 0.1 mol L-1. In general, the HCl 0.1 mol L-1 solution extracted the highest amounts of the studied micronutrients. Mehlich-1 extracted the […]
Nitrate percolation in a Typic Hapludox amended with urban compost waste or inorganic fertilization
01/Sep/2001
The movement of nitrate in soil percolate was evaluated in a field experiment using a Typic Hapludox cultivated with sugarcane and amended with urban compost waste or inorganic fertilizer. The experiment, conducted during the years of 1996/97 and 1997/98, had the following treatments: lime + inorganic fertilization, and control and urban compost waste applied in three levels: 20, 40 and 60 Mg ha-1 (dry weight basis). In the second year (1997/98), the urban compost waste was applied to soil in […]
