Carbon (C) addition through crop residues (residue-C), C dioxide emission (CO2-C) and the soil C stock (soil-C) are components of the C cycle in the soil-plant-atmosphere system. This 18-year study was conducted to identify agricultural practices that could potentially increase C retention in the soil and lessen global warming trends. The three C pools (residue-C, CO2-C and soil-C) under different tillage systems (CT-conventional tillage and NT-no tillage) and cropping systems (O/M-oat (Avena strigosa Schreb)/maize (Zea mays L.) and V/M-vetch (Vicia […]

This study had the objective of characterizing the main soil types cultivated with melon, based on physical features, in the Apodi Tableland, state of Rio Grande do Norte, to provide basic information for an adequate soil and crop management. Three soil types were studied, in September 2003: Cambissolo Háplico Ta eutrófico típico – CXve (Typic Haplocambids), Latossolo Vermelho-Amarelo eutrófico típico – LVAe (Typic Eutrotorrox) e Argissolo Vermelho distrófico arênico – PVd (Arenic Kandiustults). A general analysis of the soil physical […]

To evaluate the effect of soil tillage and management of winter cover crops (black oat + radish intercrop) on the soil temperature, an experiment was conducted in a Nitossol (Alfisol) in Botucatu, state of São Paulo, Brazil, in the 2000 fall/winter season. A design in randomized blocks was used in a 3 x 3 factorial scheme (three tillage and three cover crop managements). Soil tillage consisted of: conventional tillage, conservation tillage with chiseling, and no-tillage. The cover crops managements included plant killing […]

The agroforestry systems have been widely promoted as one sustainable agricultural system, mainly for developing areas, where the external use of resources are not feasible. The aim of this study was to evaluate the impact of one conventional and four agroforestry systems on the contents of total soil nitrogen, mineral nitrogen and different organic nitrogen fractions after five years of experimental cultivation on a Luvisol (Alfisol). The study area was in the semi-arid zone at the National Caprine Research Center […]

The understanding of the relationships between geology, geomorphology and pedology underlies activities of soil classification and the evaluation of the pedological distribution of an area. This study was motivated by the lack of reports of this nature for the region of Lavras (MG), where several soil classes occur, related to a great petrological variety in the parent material and different geomorphological domains. The objective was to study the relationships between parent materials (pedogeological relationship), relief classes (pedogeomorphological relationship) and soils […]

The total organic carbon (TOC) in soils can be estimated by dry and humid combustion methods. Both have some drawbacks, mainly the humid combustion, which demands high reagent quantities and generates toxic waste containing chromium. The Mebius in Block method was developed to decrease the quantity of Na dichromate used in analyses. The objectives of this study were to verify the precision and accuracy of the Mebius in Block compared with other wet and dry combustion methods. The study was […]

The field capacity, or its equivalent for soils in pots, the “pot capacity”, is an important parameter for irrigation management. We aimed to determine both water content and water loss as a function of time in pots filled with material of a clayey and a medium-textured soil. From these data the pot capacity water content was estimated using different criteria. It was concluded that the final water content extrapolated from the observed q-t curve is a good estimator of the […]

The inadequate use of soils induces alterations, exhausting the productivity, and resulting in growing areas of degraded soil. This study had the objectives of a) studying alternatives to promote the formation of the A horizon of a degraded soil through the use of green manure, sewage sludge, and cultivation of a native tree species; and b) selecting soil quality indicators to detect the alterations in the surface layer. Evaluations were executed annually. The experimental design was in random blocks with […]

Different physical properties are used to evaluate the soil physical quality. In this context, soil tensile strength and friability are indicators of the soil physical and structural quality. The objective of this study was to quantify the tensile strength and friability of an Oxisol under different soil use systems: forest, fallow and cultivated. Soil samples were collected from three contiguous areas of an Experimental Farm of the State University of Maringá. Two areas were cultivated: one with annual crops under […]

Manganese (Mn) toxicity may be a constraint for crop production in acid soils of tropical regions. However, variations of Mn concentrations in plant tissues are also related to the genotypic differences. A greenhouse experiment was carried out to evaluate Mn tolerance of three soybean cultivars [Glycine max (L.) Merrill]. Cultivars Santa Rosa, IAC-15 and IAC-Foscarin 31 were evaluated under five Mn rates (2, 100, 150, 200, and 250 µmol L-1) in nutrient solution (pH 5.0). The experiment in randomized blocks was a 5 x 3 factorial […]