Compaction is one of the main causes of yield decreases in agricultural soils. Mechanical chiseling has been suggested to reduce soil compaction in long-term no-tillage systems. Another option to alleviate soil compaction is the use of cover crops, such as forage radish, with a well-developed tap root system and the capacity of growing into soil compacted layers, forming stable biopores and improving the soil physical properties. This study aimed to evaluate the efficiency of a mechanical (chisel plow) and biological […]

The presence of plants stimulates soil microbiota, which may contribute to soil remediation. It is of great interest to quantify these effects on heterotrophic microorganisms due to their practical and ecological relevance. The following factors were evaluated: bacterial cell density, enzymatic activity, bacterial community structure and the spontaneous occurrence of arbuscular mycorrhizal fungi (AMF) in the plant rhizosphere in an area of land farming of petrochemical wastes, using a rhizospheric soil under five plants and control soil without plants. The […]

Among the different forms of water erosion, interrill erosion is one of the most deleterious to the productivity of soils used in agriculture, causing losses of soil, water and nutrients. This study sought to evaluate the efficiency of environmental protection by the Shrub cover types caatinga, Guandu (Cajanus cajan) and sweet potato (Ipomoea potatoes Lam) as compared to bare soil, as well as the effect of these crops on the interrill erosion and hydraulic properties of surface runoff in a […]

Mathematical models are used to estimate the nitrogen (N) mineralization potential in the soil. The parameters of anaerobic decomposition can be used to predict N availability to flooded rice. The objective of this study was to determine the “potentially mineralizable N” (N0) and the “mineralization rate” (k) parameters, using five mathematical models for different paddy soils of the state of Rio Grande do Sul (RS), Brazil, and to correlate the N0 values from the models with N uptake of flooded […]

The objectives of this study were to evaluate the influence of three soil cover species Acacia auriculiformis, Mimosa caesalpiniifolia and Corymbia citriodora compared to pasture and natural secondary forest on soil chemical and microbial attributes. The field survival rate of the species reached over 70% and the development in height and diameter (DAP) was adequate. The survival rate of Mimosa caesalpiniifolia was the highest among the legume species, while the development of Acacia auriculiformis was the best, mainly between 27 […]

In the humid tropics the buildup and maintenance of soil fertility are major challenges in terms of sustainability of agroecosystems. The objective of this study was to evaluate an alley cropping system with pigeon pea (Cajanus cajan) on an Alfisol, with annual application of lime and potassium, with special concern regarding the viability of this system as an alternative to slash and burn practiced in tropical agriculture. Pigeon pea and maize (Zea mays) were planted in the experiment with the […]

Organic matter may be considered an important soil quality indicator, as it is related with many soil chemical, physical, and biological characteristics. The study of total organic carbon (TOC) of the soil and its fractions is important. This study was conducted in a micro basin, with the purpose of: analyzing characteristics and quantify the stocks of total organic carbon (TOC) and its fractions as evidence of soil quality after different forms of use: (1) Atlantic Forest, (2) Cocoa (Theobroma cacao), […]

Surface lime application to an acid soil under no-till system and normal rainfall conditions increases yield and crop root growth near the soil surface, but the effects of lime sources like flue dust, sewage sludge and aqueous lime have not been fully investigated . The experiment aimed to evaluate the effects of surface application of different lime sources on soil chemical attributes of a clayey, dystrophic Oxisol and black oat root growth and yield under a no-till system. Evaluations were […]

Hydrogels based on polyacrylamide (PAAm) were synthesized and their efficiency for the controlled release of ammonium and potassium contained in fertilizers evaluated. The hydrogels were synthesized by polymerizing acrylamide (AAm) in aqueous solution at two acrylamide concentrations (3.6 and 21.7 %) using N-N’-methylene-bisacrylamide (MBAAm) as cross-linker and N,N,N’,N’ tetramethylethylenediamine (TEMED) as catalytic agent. Nutrient fixation was performed by immersion of hydrogels in aqueous nutrient solutions with 86 and 82 mg L-1 K+ and NH4+. The hydrophilic, spectroscopic and morphological properties […]

An earlier application of potassium fertilizer, in the cultivation of cover crop species preceding the main summer crop in no-tillage system can be an advantageous in commercial farming. The objective of this study was to evaluate grain yield and K accumulation in soybean due to an earlier application of potassium fertilizer to a pear millet cover crop, and compared to K applied at sowing of the subsequent soybean under no-tillage. The experiment was conducted at the Faculdade de Ciências Agronômicas […]