The objective of this work was to determine carbon and nitrogen content in the soil microbial biomass by comparing microwave radiation and chloroform fumigation using the extraction and incubation methods. Two soil samples (Dark-Red Podzolic) were submitted to incubation and extraction after chloroform fumigation and microwave radiation during different periods (2, 5, 10, 15, 20, 30, 40 and 50 min). Two minutes under microwave radiation were sufficient to determine C and N content in the soil biomass using incubation and […]

The most probable number (MPN) for soil bacteria and fungi was determined using a micro-assay technique, which was more economical and less tedious. This technique was compared with the conventional procedure for counting soil microorganisms in soil samples with different textures. The sensitivity of this method could be also verified when used to evaluate number of microorganisms from different sources of organic matter and chromium added to the soil.

The characterization and quantification of soil organic matter as water soluble carbon, labile carbon and light organic matter may be used to characterize the rehabilitation of degraded areas. Soil samples were thus collected on a hillside cut submitted to reclamation, presenting different types of vegetal covering during November 1994, in the district of Viçosa. The treatments consisted of areas of soils without vegetation, recovering areas with mainly legumes, recovering areas with mainly grass, soils under grass and soils under natural […]

Organic matter is considered the soil attribute most sensitive to the changes triggered by the management systems. The objective of this study was to evaluate the effect of nine years using three soil tillage systems -conventional tillage, reduced tillage and no tillage- on soil chemical characteristics of a Humic Cambisol in southern Brazil. Soil samples were collected in September 1996 at depths of 0-2, 2-5, 5-10, 10-15, and 15-20 cm, and analysed for C and N contents in total organic […]

The macronutrient removal by both cashew nut and apple was evaluated in orchards of two dwarf clones in a field without irrigation and fertilization on a Red-Yellow Podzolic at Pacajus Experimental Station (Centro Nacional de Pesquisa de Agroindústria Tropical (CNPAT/EMBRAPA)), in Pacajus, Ceará, Brazil, from March/94 to April/95. CCP-76 and CCP-09 cashew clones did not differ with regard to the macronutrient quantities removed by the cashew nut and cashew apple, except for Ca. This macronutrient was removed in greater quantity […]

This work was based on six experiments carried out in the northwestern region of the state of São Paulo, using six common varieties of sugarcane. The soil of each locality was classified and both deformed and undeformed samples of soils were collected in a 150 cm deep profile, by horizon, for chemical, physical and physico-hydric characterization. Data on climate and sugarcane plant-cane yield for the 96/97 harvest season were also collected. To determine which factors were better correlated with productivity, […]

Through profile morphology and physical analysis (texture, bulk and particle densities, pore size distribution, water storage and retention, and field capacity determined “in situ”), the behavior of a yellow Latosol located in Cruz das Almas (BA), Brazil, was studied when subjected to irrigation. The results made showed that the AB and BA horizons were hard (cohesion), mainly when dry, becoming a strong mechanic impediment fot root growth , aeration and water movement; due to the presence of the hard layer, […]

Shoot growth, phosphorus uptake (PC) and utilization efficiency (PUE) of Eucalyptus grandis seedlings associated to Glomus etunicatum (Ge) and, or, Pisolithus tinctorius (Pt), in different P rates and soil water potentials (ψ), were evaluated in a greenhouse experiment with two geminated pots, using a split-root technique. One of the pots in the geminated set contained the treatments, arranged in a factorial scheme of two P rates (P60 and P120, corresponding to additions of 60 and 120 mg dm-3 soil), three […]

Understanding the chemistry behavior in acid soils during the decomposition of plant residues is very important for the management of these soils. The effects of incubation (0, 15, 30, 60 and 90 days) of finely ground residues of oil seed radish (Raphanus sativus), soybean (Glycine max) and wheat (Triticum aestivum) (at 2 and 4%) with samples of Bw horizon of three Oxisols of the state of Paraná, Brazil, on the soil pH, dissolved organic carbon (DOC) and soluble and exchangeable […]

This study was conducted to examine the distribution and nature of Fe oxides in plinthic soils on the sediments of Barreiras Group (in the state of Piauí) and Itapecuru Formation (in the state of Maranhão) in Northeastern Brazil. Four pedons were selected: a “plinthic, dystrophic, epieutrophic Gray Podzolic with low activity clay” and a “dystrophic Plinthosol with low activity clay” (both Plinthic Kandiustalfs) on the Barreiras sediments, as well as an “eutrophic Plinthosol with low activity clay” and an “allic […]