Volume 34, Number 2, 2010

Tobacco farmers of southern Brazil use high levels of fertilizers, without considering soil and environmental attributes, posing great risk to water resources degradation. The objective of this study was to monitor nitrate and ammonium concentrations in the soil solution of an Entisol in and below the root zone of tobacco under conventional tillage (CT), minimum tillage (MT) and no-tillage (NT). The study was conducted in the small-watershed Arroio Lino, in Agudo, State of Rio Grande do Sul, Brazil. A base […]

The effectiveness of soil sampling plans may be increased if the spatial variability of soil properties is known and taken into consideration; the factors that determine it should therefore be studied. The objective of this paper was to evaluate the spatial variability of the contents P, K, Ca, Mg, and S in two Oxisols, one very clayey and the other with medium texture, managed in a similar system for eight years, in no-tillage. Soil samples were collected at regular distances […]

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 […]

The tilling of areas in no-tillage to several years and the use of gypsum practices are observed among the farmers in southwestern Goiás. This study was carried out to evaluate the effect of gypsum rates (0, 1, 2, 4 e 6 Mg ha-1) on some chemical attributes in the soil’s depth and in soybean yield in area under long-term no-till, with and without tillage. A complete randomized block scheme with a split-split-plot design with four replicates was used. The area […]

In Brazil, plant-available Zn in the soil is determined by several chemical procedures, of which the most commonly used are Mehlich-1 and DTPA. The objective of this study was to evaluate Zn availability in soils of Minas Gerais State, under different Zn and lime rates, using the extractors Mehlich-1, Mehlich-3 and DTPA and maize as indicator plant. Seven soil samples were incubated with lime to reach pH 6.0. The samples were treated with Zn in the form of ZnSO4, in […]

This study aimed to establish curves of macronutrient accumulation in sunflower. The experiment was conducted in the field on a Typic Hapludox, at the experimental station of Embrapa Soja in Londrina, State of Paraná. The plots consisted of 14 25 m long rows spaced 0.70 m apart, resulting in a total area of 245 m2, with four replications. Prior to sowing a fertilization seeding of 300 kg ha-1 of 05-20-20 NPK fertilizer was applied. Fertilization was split in two applications […]

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 […]

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 […]

Dairy cattle in South Brazil is raised mainly in a system based on partial or total confinement of the animals, generating a significant amount of residues. The residues have been used as the only nutrient source or associated to mineral sources in grain or silage production. Their effect on soil characteristics has however been little explored. This study was conducted to evaluate the influence of fertilization rates with liquid dairy cattle manure associated with mineral fertilizer on P, K, C, […]

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 […]