Mineralogy and micromorphology of cohesive horizons in oxisols and ultisols of the coastal tablelands of Alagoas, Brazil
01/Apr/2010
The cohesive character is a property of subsurface soil horizons with hard to extremely hard consistency when dry, and friable or firm when wet. Despite the agricultural importance, the formation of these horizons has not been fully explained. The objective of this study was a chemical, mineralogical and micromorphological characterization of cohesive soils of the Coastal Tablelands in Northeast Brazil, to understand their pedogenesis and identify properties for the definition of the cohesive character by the Brazilian System of Soil […]
Phosphorus concentration changes in soils under flooded rice in Rio Grande do Sul, Brazil
01/Apr/2010
Soils used for production of flooded rice in the state of Rio Grande do Sul are originated from different parent materials, resulting in different characteristics that affect P availability for the crop. The aim of this paper was to verify the differences in P availability for rice in soils originated from different parent materials. The experiment was carried out in a complete randomized block design, where five soils were exposed to absence or presence of triple superphosphate. In the soils […]
Soil-applied silicon decreases severity of wheat spot blotch on silicon-deficient soils
01/Apr/2010
Spot bloth caused by Bipolaris sorokiniana is an important wheat desease mainly in hot and humid regions. The aim of this study was to evaluate the response of wheat to different sources and modes of Si application, as related to the severity of wheat spot blotch and plant growth, in two Si-deficient Latosols (Oxisols). An greenhouse experiment was arranged in a 2 x 5 factorial completely randomized design, with eight replications. The treatments consisted of two soils (Yellow Latosol and […]
Soil surface roughness under diferent management systems and artificial rainfall
01/Apr/2010
Soil roughness is influenced by soil management, particularly by soil tillage and mainly reduced by rainfall action. This study aimed to evaluate the influence of different systems of soil management and artificial rainfall application on soil surface roughness. The treatments were a result of the combination of three systems: no-tillage, conventional tillage and minimum tillage, with three levels of dry soybean (Glycine max L. Merrill): residue: 0; 2; and 4 Mg ha-1. Experimental units received artificial rain (seven rains), at […]
Sewage sludge as nitrogen and phosphorus source for cane-plant and first ratoon crops
01/Apr/2010
The use of sewage sludge in Brazilian agriculture was regulated by the resolution no. 375 Conama, in 2006. However, there is a lack of research to adequate the mineral N and P fertilizer doses to be applied in agricultural fields treated with this residue. In a field experiment, the effects of application rates of sewage sludge and mineral N and P fertilizers on the productivity and technical characteristics of the cane-plant and first ratoon (residual effect) crops were evaluated. Four […]
Potential of soil carbon sequestration in different biomes of Brazil
01/Apr/2010
Soil is an important pool for C stocks and plays a fundamental role in greenhouse gas emissions and consequently in climatic changes. Land use change can cause either a negative or a positive effect in terms of greenhouse gas emissions to the atmosphere. However, the intensification of global warming has been confirmed, related mainly to the increase of greenhouse gas emissions from burning of fossil fuel, deforestation, and adoption of inadequate agricultural land management practices. An inadequate soil use does […]
Organic matter contents and characteristics in hydromorphic soils of the State de Espirito Santo
01/Apr/2010
Soil organic matter (SOM) contents and characteristics are results of production, incorporation, decomposition, alteration, and mineralization rates, according to environmental conditions. In hydromorphic soils, SOM dynamics are regulated by O2 deficit, lowering the decomposition rates and producing substances different from those in well-drained soils. This article aimed to determine SOM contents and characteristics at three locations in the State of Espirito Santo, Brazil. Total organic carbon (TOC) was quantified by three methods, besides partitioning humic substances (HS) and determining the […]
Dry matter production and nutrient accumulation after successive crops of lettuce, tomato, rice, and andropogongrass in a substrate with zeolite
01/Apr/2010
Zeolites are hydrated crystalline aluminosilicate minerals of natural occurrence, structured in rigid third dimension net that can be used as slow release plant-nutrient source. The main objective of this study was to evaluate the effects of plant growth substrate under zeolite application, enriched with N, P and K, on dry matter yield and on nutrient contents in consecutive crops of lettuce, tomato, rice, and andropogon grass. The experiment was carried out in a greenhouse, with 3 kg pots with an […]
Selection of growth-promoting bacteria for pineapple ‘Vitória’ during acclimatization
01/Apr/2010
Pineapple (Ananas comosus L. Merrill) in vitro propagation results in the production of a large quantity of healthy and homogeneous plantlets. Despite these advantages, the long time required for acclimatization makes this agricultural practice too costly. Growth acceleration of plantlets by inoculation with endophytic and epiphytic diazotrophic bacteria may be useful to reduce this period. The objectives of this study were to evaluate the potential of 20 diazotrophic bacteria strains in synthesizing indole, solubilizing Ca phosphate and Zn oxide and […]
Soils in the Yanomami indigenous area in the mid-Catrimani River – Roraima
01/Apr/2010
In Roraima, the spatial distribution of indigenous peoples indicates a background of constant search for soils capable of sustaining shift cultivation. This study aimed to establish a relationship between the understanding of soil by the Yanomami tribe from the mid-Catrimani river region and the Brazilian System of Soil Classification and evaluate the type of agricultural land use according to soil fertility tests, in two steps. The first consisted of visiting eight Indian communities to collect soil samples at 21 sites […]